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  • 1.
    Abrahamsson, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Accelerator mass spectrometry group. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Wolpher, Henriette
    Johansson, Olof
    Larsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Kritikos, Mikael
    Eriksson, Lars
    Norrby, Per-Ola
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Sun, Licheng
    Åkermark, Björn
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    A New Strategy for the Improvement of Photophysical Properties in Ruthenium(II) Polypyridyl Complexes: Synthesis and Photophysical and Electrochemical Characterization of Six Mononuclear Ruthenium(II) Bisterpyridine-Type Complexes2005In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 44, no 9, p. 3215-3225Article in journal (Refereed)
  • 2.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Tranvik, Lars
    Gogoll, Adolf
    Waldebäck, Monica
    Markides, Karin
    Rydin, Emil
    Depth attenuation of biogenic phosphorus compounds in lake sediment measured by 31P NMR2005In: Environmental Science and Technology, ISSN 0013-936, Vol. 39, no 3, p. 867-872Article in journal (Refereed)
  • 3.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Waldebäck, Monica
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Sediment Depth Attenuation of Biogenic Phosphorus Compounds Measured by 31P NMR2005In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 39, no 3, p. 867-872Article in journal (Refereed)
    Abstract [en]

    Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using 31P NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these compound groups are about 10 yr for pyrophosphate and 2 decades for mono- and diesters. Probably, these compounds will be mineralized to ortho-P and is thus potentially available for recycling to the water column, supporting further growth of phytoplankton. In conclusion, 31P NMR is a useful tool to asses the bioavailability of certain P compound groups, and the combination with traditional fractionation techniques makes quantification possible.

  • 4.
    Amirkhani, Ardeshir
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rajda, Cecilia
    Arvidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bencsik, Krisztina
    Boda, Krisztina
    Seres, Erika
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Vecsei, Laszlo
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Interferon-beta affects the tryptophan metabolism in multiple sclerosis patients2005In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 12, no 8, p. 625-631Article in journal (Refereed)
    Abstract [en]

    Tryptophan and its metabolites are of great interest in understanding the pathogenesis of multiple sclerosis (MS). The total levels of tryptophan and its metabolites, kynurenine and kynurenic acid were determined in plasma by capillary liquid chromatography electrospray ionisation tandem mass spectrometry. This is the first report of the plasma levels of these analytes in healthy controls and relapsing-remitting MS patients receiving long-term and acute interferon-beta (IFN-beta) treatment. Twenty-four hours post-administration increased kynurenine levels (first IFN MS versus healthy, P = 0.042) and kynurenine/tryptophan ratio (K/T; first IFN MS versus healthy, P =0.027; first IFN MS versus long-term IFN MS, P = 0.036) were found. The long-term IFN MS group had higher K/T ratios at 4 and 12 h post-administration (P = 0.015 and 0.009, respectively). The increase of K/T ratio in the first IFN MS group indicate an induction of the enzyme indolamine-2,3-dioxygenase (IDO), as reported earlier in experimental allergic encephalomyelitis. As IDO is participating in both inflammatory and neurodegenerative processes, further knowledge of its involvement in the pathogenesis of MS is of great importance.

  • 5.
    Arvidsson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Ryder, Neil S.
    Weiss, H. Markus
    Hook, David F.
    Escalante, Jaime
    Seebach, Dieter
    Exploring the Antibacterial and Hemolytic Activity of Shorter- and Longer-Chain B-, a,B-, and y-Peptides, and of B-Peptides from B2-3-Aza- and B3-2-Methylidene-amino Acids Bearing Proteinogenic Side Chains - A Survey2005In: Chemistry & Biodiversity, Vol. 2, p. 401-420Article in journal (Refereed)
    Abstract [en]

    The antibacterial activities of 31 different b-, mixed a/B-, and y-peptides, as well as of B-peptides derived from B2-3-aza- and B3-2-methylidene-amino acids were assayed against six pathogens (Enterococcus faecails, STaphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa), and the results were compared with literature data. The interaction of these peptides with mammalian cells, as modeled by measuring the hemolysis of human erythrocytes, was also investigated. In addition to those peptides designed to fold into amphiphilic helical conformations with positive charges on one face of the helix, one new peptide with hemolytic activity was detected within the sample set. Moreover, it was demontrated that neither cationic peptides used for membrane translocation (B3-oligoarginines), nor mixeda/B- or y-peptides with somatostatin-mimicking activities display unwanted hemolytic activity.

  • 6. Bazoti, Fotini N.
    et al.
    Tsarbopoulos, Anthony
    Markides, Karin E.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Study of the non-covalent interaction between amyloid-b-peptide and melatonin using electrospray ionization mass spectrometry2005In: Journal of Mass Spectrometry, no 40, p. 182-192Article in journal (Refereed)
    Abstract [en]

    Oxidative stress and unregulated immune response are believed to play a key role in the processes inherent to Alzheimer's disease (AD). The fact that free radicals can result in neurodegeneration suggests that actions against reactive oxygen species may be beneficial in treating and preventing AD. In the light of the suggested link between oxidative stress and AD, it is proposed that antioxidants and, even more, endogenous antioxidants may offer a therapeutic regime for protection against the risk of this disease. For this reason, the formation of non-covalent complexes between amyloid-b-peptide (Ab) or its oxidized forms and melatonin was studied by quadrupole and Fourier transform ion cyclotron resonance electrospray ionization mass spectrometry. The stability of the non-covalent complex was examined under several experimental conditions, such as orifice voltage, pH, presence of organic modifier, concentration and time. Two different digestion protocols combined with mass spectrometric analysis of the resulting peptide fragments were employed in order to locate the binding site of melatonin in Ab.

  • 7.
    Bergström, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Integrated Micro-Analytical Tools for Life Science2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Advances in life science require knowledge of active molecules in complex biological systems. These molecules are often only present for a certain time and at limited concentrations. Integrated micro-analytical tools for sampling, separation and mass spectrometric (MS) detection would meet these requests and are therefore continuously gaining interest. An on-line coupling of analytical functions provides shorter analysis time and less manual sample handling. In this thesis, improved compatibility of microdialysis sampling and multidimensional separations coupled to MS detection are developed and discussed.

    Microdialysis was used in vitro for determination of the non-protein bound fraction of the drug ropivacaine. The sampling unit was coupled on-line to capillary column liquid chromatography (LC) followed by ultraviolet or MS detection. For MS detection, the system was extended with a desalting step and an addition of internal standard. A method for MS screening of microdialysates, collected in vivo, was also developed. The method involved sampling and measurements of the chemical pattern of molecules that generally are ignored in clinical investigations. Chemometric tools were used to extract the relevant information and to compare samples from stimulated and control tissues.

    Complex samples often require separation in more than one dimension. On-line interfaces for sample transfer between LC and capillary electrophoresis (CE) were developed in soft poly(dimethylsiloxane) (PDMS). MS detection in the LC-CE system was optimised on frequent sampling of the CE peak or on high resolution in mass spectra using time-of-flight (TOF)MS or Fourier transform ion cyclotron resonance (FTICR)MS, respectively. Aspects on electrode positioning in the LC-CE interface led to development of an on-column CE electrode. A successful method for deactivation of the PDMS surface using a polyamine polymer was also developed. The systems were evaluated using peptides and proteins, molecules that are gaining increased attention in bioscience, and consequently also in chemical analysis.

    List of papers
    1. Determination of the free concentration of ropivacaine in plasma by packed capillary liquid chromatography: A comparison of ultrafiltration and microdialysis as sample preparation methods
    Open this publication in new window or tab >>Determination of the free concentration of ropivacaine in plasma by packed capillary liquid chromatography: A comparison of ultrafiltration and microdialysis as sample preparation methods
    2001 (English)In: Journal of Microcolumn Separations, ISSN 1040-7685, E-ISSN 1520-667X, Vol. 13, no 5, p. 197-201Article in journal (Refereed) Published
    Abstract [en]

    In this study, ultrafiltration and microdialysis have been compared as sample preparation methods to separate the free fraction of ropivacaine from the protein bound in 150 μL plasma. A liquid chromatographic system with packed capillary columns (0.2 mm internal diameter) was used to enhance sensitivity when analyzing the small sample volumes obtained after the ultrafiltration and the microdialysis. The microdialysis was performed with probes of our own construction, and to save analysis time, the microdialysis sampling was coupled on-line to the liquid chromatographic system. The reduction of back pressure in the microdialysis outlet tube and in the injector was found to be essential. The free fraction obtained with each method was equivalent: both gave a free fraction of 6%.

    Keyword
    microdialysis, ultrafiltration, free fraction, ropivacaine, capillary liquid chromatography
    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-93670 (URN)10.1002/mcs.1042 (DOI)
    Available from: 2005-10-28 Created: 2005-10-28 Last updated: 2017-12-14Bibliographically approved
    2. On-line coupling of microdialysis to packed capillary column liquid chromatography-tandem mass spectrometry demonstrated by measurement of free concentrations of ropivacaine and metabolite from spiked plasma samples
    Open this publication in new window or tab >>On-line coupling of microdialysis to packed capillary column liquid chromatography-tandem mass spectrometry demonstrated by measurement of free concentrations of ropivacaine and metabolite from spiked plasma samples
    2002 (English)In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 775, no 1, p. 79-87Article in journal (Refereed) Published
    Abstract [en]

    An on-line coupling of microdialysis to a packed capillary column switching liquid chromatographic system (0.2 mm I.D.) and mass spectrometric detection was developed. The microdialysates were collected in the loop of the first of three valves, coupled in direct series. A deuterated internal standard was added on-line by the middle valve and the third valve operated both a pre-column, for desalting of the physiological buffer used in the sampling procedure, and a separation column. The on-line system was used to study free concentrations of ropivacaine and its metabolite (PPX) in human plasma samples. The analytes were detected by electrospray ionization in a tandem mass spectrometer operating in multiple reaction monitoring mode. The free fractions of ropivacaine (200 nM total concentration) and PPX (20 nM total concentration) in spiked plasma samples were 12±3 and 47±5% (±standard deviation for day-to-day variations, n=3), respectively.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-93671 (URN)10.1016/S1570-0232(02)00280-5 (DOI)
    Available from: 2005-10-28 Created: 2005-10-28 Last updated: 2017-12-14Bibliographically approved
    3. Screening of microdialysates using on-line desalting and mass spectrometric detection
    Open this publication in new window or tab >>Screening of microdialysates using on-line desalting and mass spectrometric detection
    Show others...
    In: J. Chromatogr. AArticle in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-93672 (URN)
    Available from: 2005-10-28 Created: 2005-10-28Bibliographically approved
    4. On-column polymer-imbedded graphite inlet electrode for capillary electrophoresis coupled on-line with flow injection analysis in a poly(dimethylsiloxane) interface
    Open this publication in new window or tab >>On-column polymer-imbedded graphite inlet electrode for capillary electrophoresis coupled on-line with flow injection analysis in a poly(dimethylsiloxane) interface
    Show others...
    2003 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 24, no 11, p. 1723-1729Article in journal (Refereed) Published
    Abstract [en]

    A method for coupling an electrophoretic driven separation to a liquid flow, using conventional fused-silica capillaries and a soft polymeric interface is presented. A novel design of the electrode providing high voltage to the electrophoretic separation was also developed. The electrode consisted of a conductive polyimide/graphite imbedded coating immobilized onto the capillary electrophoresis (CE) column inlet. This integrated electrode gave the same separation performance as a commonly used platinum electrode. The on-column electrode also showed good electrochemical stability in chronoamperometric experiments. In addition, with this electrode design, the electrode position relative to the inlet end of the CE column will always be constant and well defined. The on-line flow injection analysis (FIA)-CE system was used with electrospray ionization (ESI)-time of flight (TOF)-mass spectrometry detection. The preparation of the PDMS (poly(dimethylsiloxane)) interface for FIA-CE is described in detail and used for initial tests of the on-column polymer-imbedded graphite inlet electrode. In this interface, a pressure-driven liquid flow, a make up CE electrolyte and a CE column inlet meet in a two-level cross (95 μm ID) in the PDMS structure, enabling independent flow characterization.

    Keyword
    Capillary electrophoresis, Flow injection, Hyphenation, On-column electrode, Poly(dimethylsiloxane)
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94267 (URN)10.1002/elps.200305362 (DOI)
    Available from: 2006-04-07 Created: 2006-04-07 Last updated: 2017-12-14Bibliographically approved
    5. Development of a poly(dimethylsiloxane) interface for on-line capillary column liquid chromatography-capillary electrophoresis coupled to sheathless electrospray ionization time-of-flight mass spectrometry
    Open this publication in new window or tab >>Development of a poly(dimethylsiloxane) interface for on-line capillary column liquid chromatography-capillary electrophoresis coupled to sheathless electrospray ionization time-of-flight mass spectrometry
    2003 In: Anal. Chem., ISSN 0003-2700, Vol. 75, no 20, p. 5461-5467Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93674 (URN)
    Available from: 2005-10-28 Created: 2005-10-28Bibliographically approved
    6. Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments
    Open this publication in new window or tab >>Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments
    Show others...
    2005 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 3, p. 938-942Article in journal (Refereed) Published
    Abstract [en]

    The poly(dimethylsiloxane) (PDMS) material provides a number of advantageous features, such as flexibility, elasticity, and transparency, making it useful in integrated analytical systems. Hard fused-silica capillary structures and soft PDMS channels can easily be combined by a tight fit, which offers many alternatives for structure combinations. PDMS and fused silica are in different ways prone to adsorption of low levels of organic compounds. The need for modification of the inner wall surface of PDMS channels may often be necessary, and in this paper, we describe an easy and effective method using the amine-containing polymer PolyE-323 to deactivate both fused-silica and PDMS surfaces. The adsorption of selected peptides to untreated surfaces was compared to PolyE-323-modified surfaces, using both radionuclide imaging and capillary electrophoresis experiments. The polyamine modification displayed a substantially reduced adsorption of three hydrophobic test peptides compared to the native PDMS surface. Filling and storage of aqueous solution were also possible in PolyE-323-modified PDMS channels. In addition, hybrid microstructures of fused silica and PDMS could simultaneously be deactivated in one simple coating procedure.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-93675 (URN)10.1021/ac0492618 (DOI)
    Available from: 2005-10-28 Created: 2005-10-28 Last updated: 2017-12-14Bibliographically approved
    7. A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
    Open this publication in new window or tab >>A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
    Show others...
    2006 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 131, no 7, p. 791-798Article in journal (Refereed) Published
    Abstract [en]

    Information on protein expression, disease biomarkers or surrogate markers and genetic disorders can nowadays be achieved from analysis of complex biological samples by liquid separation coupled to mass spectrometric (MS) detection. This paper describes fast multidimensional separation by on-line liquid chromatography (LC) and capillary electrophoresis (CE), followed by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) MS detection. This detector provides ultrahigh resolution of the detected ions, mass accuracy at the ppm-level and high sensitivity. Most of the challenge of this system lies in the development of a new interface for the on-line coupling of LC to CE. The interface developed in poly(dimethylsiloxane) provides a RSD for injection repeatability of <3.5% and surface control for unspecific binding by deactivation with a cationic polymer, PolyE-323. We have evaluated the interface, as well as the overall system, with respect to robustness and deconvolution ability. Sequence coverage for bovine serum albumin (BSA) of 93% showed a high recovery of sample in the different transfer steps through the system. The detection limit for identification is 277 ng mL−1 (or 280 nM) on average for peptides. In the future, we expect LC-CE-MS to be a novel strategy for elucidating the chemistry of biological matrices.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-80932 (URN)10.1039/b601660j (DOI)
    Available from: 2006-06-29 Created: 2006-06-29 Last updated: 2017-12-14Bibliographically approved
    8. Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
    Open this publication in new window or tab >>Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
    Show others...
    2005 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 16, p. 5356-5363Article in journal (Refereed) Published
    Abstract [en]

    A microchip in poly(dimethylsiloxane) (PDMS) for in-line solid-phase extraction-capillary electrophoresis-electrospray ionization-time-of-flight mass spectrometry (SPE-CE-ESI-TOF-MS) has been developed and evaluated. The chip was fabricated in a novel one-step procedure where mixed PDMS was cast over steel wires in a mold. The removed wires defined 50-um cylindrical channels. Fused-silica capillaries were inserted into the structure in a tight fit connection. The inner walls of the inserted fused-silica capillaries and the PDMS microchip channels were modified with a positively charged polymer, PolyE-323. The chip was fabricated in a two-level cross design. The channel at the lower level was packed with 5-um hyper-cross-linked polystyrene beads acting as a SPE medium used for desalting. The upper level channel acted as a CE channel and ended in an integrated emitter tip coated with conducting graphite powder to facilitate the electrical contact for sheathless ESI. An overpressure continuously provided fresh CE electrolyte independently of the flows in the different levels. Further studies were carried out in order to investigate the electrophoretic and flow rate properties of the chip. Finally, six-peptide mixtures, in different concentrations, dissolved in physiological salt solution was injected, desalted, separated, and sprayed into the mass spectrometer for analysis with a limit of detection in femtomole levels.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-74074 (URN)10.1021/ac050495g (DOI)16097780 (PubMedID)
    Available from: 2005-08-26 Created: 2005-08-26 Last updated: 2017-12-14Bibliographically approved
  • 8.
    Bergström, Sara K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Edenwall, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Lavén, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments2005In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 3, p. 938-942Article in journal (Refereed)
    Abstract [en]

    The poly(dimethylsiloxane) (PDMS) material provides a number of advantageous features, such as flexibility, elasticity, and transparency, making it useful in integrated analytical systems. Hard fused-silica capillary structures and soft PDMS channels can easily be combined by a tight fit, which offers many alternatives for structure combinations. PDMS and fused silica are in different ways prone to adsorption of low levels of organic compounds. The need for modification of the inner wall surface of PDMS channels may often be necessary, and in this paper, we describe an easy and effective method using the amine-containing polymer PolyE-323 to deactivate both fused-silica and PDMS surfaces. The adsorption of selected peptides to untreated surfaces was compared to PolyE-323-modified surfaces, using both radionuclide imaging and capillary electrophoresis experiments. The polyamine modification displayed a substantially reduced adsorption of three hydrophobic test peptides compared to the native PDMS surface. Filling and storage of aqueous solution were also possible in PolyE-323-modified PDMS channels. In addition, hybrid microstructures of fused silica and PDMS could simultaneously be deactivated in one simple coating procedure.

  • 9.
    Buttner, Frank
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Norgren, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Zhang, Suode
    Prabpai, Samran
    Kongsaeree, Palangpon
    Arvidsson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. avd för organisk kemi.
    Cyclic B-Tetra- and Pentapeptides: Synthesis through On-Resin Cyclization and Confomrational Studies by X-Ray, NMR and CD Spectroscopy and Theoretical Calculations2005In: Chem. Eur. J., Vol. 11, p. 6145-6158Article in journal (Refereed)
    Abstract [en]

    The solution-phase synthesis of the simplest cyclic B-tetrapeptide, cyclo(B-Ala)4 (4), as well as the solidphase syntheses through side chain anchoring and on-resin cyclization of the cyclic B3-tetrapeptide cyclo-(B3hPhe-B3hLeu-B3hLys-B3hGln-) (14) and the first cyclic B3-pentapeptide cyclo- (B3hVal-B3hPhe-B3Leu- B3hLys-B3hLys-) (19) are reported. Extensive computational as well as spectroscopic studies, including X-ray and NMR spectroscopy, were undertaken to determine the preferred conformations of these unnatural oligomers in solution and in the solid state. cyclo(B-Ala)4 (4) with no chiral side chains is shown to exist as a mixture of rapidly interchanging conformers in solution, whereas inclusion of chiral side chains in the cyclo-B3-tetrapetpride causes stabilizaton of one dominating conformer. The cyclic B3-pentapeptide on the other hand shows larger conformational freedom. The X-ray structure of achiral cyclo(B-Ala)4 (4) displays a Ci-symmetrical 16-membered ring with adjacent C=O and N-H atoms pointing pair wise up and down with respect to the ring plane. CD spectorscopic examinations of all cyclic B-peptides were undertaken and revealed results valuable as starting point for further structural investigations of these entities.

  • 10. Büttner, Frank
    et al.
    Norgren, Anna S.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Organic Chemistry.
    Zhang, Suode
    Prabpai, Samran
    Kongsaeree, Palangpon
    Arvidsson, Per I.
    Cyclic β-tetra- and pentapeptides: Synthesis through on-resin cyclization and conformational studies by X-ray, NMR and CD spectroscopy and theoretical calculations2005In: Chemistry--A European Journal, ISSN 0947-6539, Vol. 11, no 21, p. 6145-6158Article in journal (Refereed)
  • 11.
    Dahlin, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Microscale Tools for Sample Preparation, Separation and Detection of Neuropeptides2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The analysis of low abundant biological molecules is often challenging due to their chemical properties, low concentration and limited sample volumes. Neuropeptides are one group of molecules that fits these criteria. Neuropeptides also play an important role in biological functions, which makes them extra interesting to analyze. A classic chemical analysis involves sampling, sample preparation, separation and detection. In this thesis, an enhanced solid supported microdialysis method was developed and used as a combined sampling- and preparation technique. In general, significantly increased extraction efficiency was obtained for all studied peptides. To be able to control the small sample volumes and to minimize the loss of neuropeptides because of unwanted adsorption onto surfaces, the subsequent analysis steps were miniaturized to a micro total analysis system (µ-TAS), which allowed sample pre-treatment, injection, separation, manipulation and detection.

    In order to incorporate these analysis functions to a microchip, a novel microfabrication protocol was developed. This method facilitated three-dimensional structures to be fabricated without the need of clean room facilities.

    The sample pre-treatment step was carried out by solid phase extraction from beads packed in the microchip. Femtomole levels of neuropeptides were detected from samples possessing the same properties as microdialysates. The developed injection system made it possible to conduct injections from a liquid chromatographic separation into a capillary electrophoresis channel, which facilitated for advanced multidimensional separations. An electrochemical sample manipulation system was also developed. In the last part, different electrospray emitter tip designs made directly from the edge of the microchip substrate were developed and evaluated. The emitters were proven to be comparable with conventional, capillary based emitters in stability, durability and dynamic flow range. Although additional developments remain, the analysis steps described in this thesis open a door to an integrated, on-line µ-TAS for neuropeptides analysis in complex biological samples.

    List of papers
    1. A feasibility study of solid supported enhanced microdialysis
    Open this publication in new window or tab >>A feasibility study of solid supported enhanced microdialysis
    Show others...
    2004 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 76, no 6, p. 1678-1682Article in journal (Refereed) Published
    Abstract [en]

    For the first time, a solid supported enhanced microdialysis methodology for analysis of neuropeptides is described. The microdialysis samples were, in this study, subsequently collected in fractions, dissolved from the solid particles, dried, and resolved in a formic acid buffer in order to make them suitable for capillary liquid chromatography-mass spectrometry. Different microdialysis flow profiles were evaluated where air-gapped continuous flow was considered most suitable for the solid supported microdialysis mode. Six endogenous neuropeptides were initially used to investigate the feasibility of this enhanced microdialysis methodology. The improved relative recovery obtained from the solid supported enhanced microdialysis was varying from no effect to 10 times higher as compared to ordinary microdialysis. The most efficient enrichment was obtained for luteinizing hormone releasing hormone, which was the largest but also the most hydrophilic of the peptides. In contrast, no significant difference in recovery was observed for Leu-enkephalin being the smallest and the most hydrophobic peptide tested. These results indicate an increased flux and selective uptake of hydrophilic peptides across the membrane and enrichment on the particles in solid supported microdialysis.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-93181 (URN)10.1021/ac035305l (DOI)15018567 (PubMedID)
    Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2017-12-14Bibliographically approved
    2. Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
    Open this publication in new window or tab >>Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
    Show others...
    2005 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 16, p. 5356-5363Article in journal (Refereed) Published
    Abstract [en]

    A microchip in poly(dimethylsiloxane) (PDMS) for in-line solid-phase extraction-capillary electrophoresis-electrospray ionization-time-of-flight mass spectrometry (SPE-CE-ESI-TOF-MS) has been developed and evaluated. The chip was fabricated in a novel one-step procedure where mixed PDMS was cast over steel wires in a mold. The removed wires defined 50-um cylindrical channels. Fused-silica capillaries were inserted into the structure in a tight fit connection. The inner walls of the inserted fused-silica capillaries and the PDMS microchip channels were modified with a positively charged polymer, PolyE-323. The chip was fabricated in a two-level cross design. The channel at the lower level was packed with 5-um hyper-cross-linked polystyrene beads acting as a SPE medium used for desalting. The upper level channel acted as a CE channel and ended in an integrated emitter tip coated with conducting graphite powder to facilitate the electrical contact for sheathless ESI. An overpressure continuously provided fresh CE electrolyte independently of the flows in the different levels. Further studies were carried out in order to investigate the electrophoretic and flow rate properties of the chip. Finally, six-peptide mixtures, in different concentrations, dissolved in physiological salt solution was injected, desalted, separated, and sprayed into the mass spectrometer for analysis with a limit of detection in femtomole levels.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-74074 (URN)10.1021/ac050495g (DOI)16097780 (PubMedID)
    Available from: 2005-08-26 Created: 2005-08-26 Last updated: 2017-12-14Bibliographically approved
    3. A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
    Open this publication in new window or tab >>A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
    Show others...
    2006 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 131, no 7, p. 791-798Article in journal (Refereed) Published
    Abstract [en]

    Information on protein expression, disease biomarkers or surrogate markers and genetic disorders can nowadays be achieved from analysis of complex biological samples by liquid separation coupled to mass spectrometric (MS) detection. This paper describes fast multidimensional separation by on-line liquid chromatography (LC) and capillary electrophoresis (CE), followed by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) MS detection. This detector provides ultrahigh resolution of the detected ions, mass accuracy at the ppm-level and high sensitivity. Most of the challenge of this system lies in the development of a new interface for the on-line coupling of LC to CE. The interface developed in poly(dimethylsiloxane) provides a RSD for injection repeatability of <3.5% and surface control for unspecific binding by deactivation with a cationic polymer, PolyE-323. We have evaluated the interface, as well as the overall system, with respect to robustness and deconvolution ability. Sequence coverage for bovine serum albumin (BSA) of 93% showed a high recovery of sample in the different transfer steps through the system. The detection limit for identification is 277 ng mL−1 (or 280 nM) on average for peptides. In the future, we expect LC-CE-MS to be a novel strategy for elucidating the chemistry of biological matrices.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-80932 (URN)10.1039/b601660j (DOI)
    Available from: 2006-06-29 Created: 2006-06-29 Last updated: 2017-12-14Bibliographically approved
    4. On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip to electrospray mass spectrometry
    Open this publication in new window or tab >>On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip to electrospray mass spectrometry
    Show others...
    In: Article in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-93184 (URN)
    Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2011-03-21
    5. Sheathless electrospray from polymer microchips
    Open this publication in new window or tab >>Sheathless electrospray from polymer microchips
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    2003 In: Analytical Chemistry, Vol. 75, no 15, p. 3934-3940Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93185 (URN)
    Available from: 2005-05-10 Created: 2005-05-10 Last updated: 2011-03-21
    6. Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip
    Open this publication in new window or tab >>Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip
    Show others...
    2005 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 130, no 2, p. 193-199Article in journal (Refereed) Published
    Abstract [en]

    Hybrid capillary-poly(dimethysiloxane) (PDMS) microchips with integrated electrospray ionization (ESI) tips were directly fabricated by casting PDMS in a mould. The shapes of the emitter tips were drilled into the mould, which produced highly reproducible three-dimensional tips. Due to the fabrication method of the microfluidic devices, no sealing was necessary and it was possible to produce a perfect channel modified by PolyE-323, an aliphatic polyamine coating agent. A variety of different coating procedures were also evaluated for the outside of the emitter tip. Dusting graphite on a thin unpolymerised PDMS layer followed by polymerisation was proven to be the most suitable procedure. The emitter tips showed excellent electrochemical properties and durabilities. The coating of the emitter was eventually passivated, but not lost, and could be regenerated by electrochemical means. The excellent electrochemical stability was further confirmed in long term electrospray experiments, in which the emitter sprayed continuously for more than 180 h. The PolyE-323 was found suitable for systems that integrate rigid fused silica and soft PDMS technology, since it simply could be applied successfully to both materials. The spray stability was confirmed from the recording of a total ion chromatogram in which the electrospray current exhibited a relative standard deviation of 3.9% for a 30 min run. CE-ESI-MS separations of peptides were carried out within 2 min using the hybrid PDMS chip resulting in similar efficiencies as for fused silica capillaries of the same length and thus with no measurable band broadening effects, originating from the PDMS emitter.

    National Category
    Analytical Chemistry Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-93084 (URN)10.1039/b414592e (DOI)15665973 (PubMedID)
    Available from: 2005-05-03 Created: 2005-05-03 Last updated: 2017-12-14Bibliographically approved
    7. Sample pretreatment on a microchip with an integrated electrospray emitter
    Open this publication in new window or tab >>Sample pretreatment on a microchip with an integrated electrospray emitter
    Show others...
    2006 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 27, no 11, p. 2075-2082Article in journal (Refereed) Published
    Keyword
    Electrospray emitter, Microchip, PDMS, Sample pretreatment
    National Category
    Chemical Sciences Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-95129 (URN)10.1002/elps.200500763 (DOI)
    Available from: 2006-11-17 Created: 2006-11-17 Last updated: 2017-12-14Bibliographically approved
  • 12.
    Dahlin, Andreas P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergström, Sara K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Andrén, Per E.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences, MMS, Medical Mass Spectrometry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip2005In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 16, p. 5356-5363Article in journal (Refereed)
    Abstract [en]

    A microchip in poly(dimethylsiloxane) (PDMS) for in-line solid-phase extraction-capillary electrophoresis-electrospray ionization-time-of-flight mass spectrometry (SPE-CE-ESI-TOF-MS) has been developed and evaluated. The chip was fabricated in a novel one-step procedure where mixed PDMS was cast over steel wires in a mold. The removed wires defined 50-um cylindrical channels. Fused-silica capillaries were inserted into the structure in a tight fit connection. The inner walls of the inserted fused-silica capillaries and the PDMS microchip channels were modified with a positively charged polymer, PolyE-323. The chip was fabricated in a two-level cross design. The channel at the lower level was packed with 5-um hyper-cross-linked polystyrene beads acting as a SPE medium used for desalting. The upper level channel acted as a CE channel and ended in an integrated emitter tip coated with conducting graphite powder to facilitate the electrical contact for sheathless ESI. An overpressure continuously provided fresh CE electrolyte independently of the flows in the different levels. Further studies were carried out in order to investigate the electrophoretic and flow rate properties of the chip. Finally, six-peptide mixtures, in different concentrations, dissolved in physiological salt solution was injected, desalted, separated, and sprayed into the mass spectrometer for analysis with a limit of detection in femtomole levels.

  • 13. Dobrovolsky, Vasily N.
    et al.
    Bowyer, John F.
    Pabarcus, Michael K.
    Heflich, Robert H.
    Williams, Lee D.
    Doerge, Daniel R.
    Arvidsson, Björn
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Casida, John E.
    Effect of arylformamidase (kynurenine formamidase) gene inactivation in mice on enzymatic activity, kynurenine pathway metabolites and phenotype2005In: Biochimica et Biophysica Acta, no 1724, p. 163-172Article in journal (Refereed)
    Abstract [en]

    The gene coding for arylformamidase (Afmid, also known as kynurenine formamidase) was inactivated in mice through the removal of a shared bidirectional promoter region regulating expression of the Afmid and thymidine kinase (Tk) genes. Afmid/Tk-deficient mice are known to develop sclerosis of glomeruli and to have an abnormal immune system. Afmid-catalyzed hydrolysis of N-formyl-kynurenine is a key step in tryptophan metabolism and biosynthesis of kynurenine-derived products including kynurenic acid, quinolinic acid, nicotinamide, NAD, and NADP. A disruption of these pathways is implicated in neurotoxicity and immunotoxicity. In wild-type (WT) mice, Afmid-specific activity (as measured by formyl-kynurenine hydrolysis) was 2-fold higher in the liver than in the kidney. Formyl-kynurenine hydrolysis was reduced by ~50% in mice heterozygous (HZ) for Afmid/Tk and almost completely eliminated in Afmid/Tk knockout (KO) mice. However, there was 13% residual formyl-kynurenine hydrolysis in the kidney of KO mice, suggesting the existence of a formamidase other than Afmid. Liver and kidney levels of nicotinamide plus NAD/NADP remained the same in WT, HZ and KO mice. Plasma concentrations of formyl-kynurenine, kynurenine, and kynurenic acid were elevated in KO mice (but not HZ mice) relative to WT mice, further suggesting that there must be enzymes other than Afmid (possibly in the kidney) capable of metabolizing formyl-kynurenine into kynurenine. Gradual kidney deterioration and subsequent failure in KO mice is consisten with high levels of tissue-specific Afmid expression in the kidney of WT but not KO mice. On this basis, the most significant function of the kynurenine pathway and Afmid in mice may be in eliminating toxic metabolites and to a lesser extent in providing intermediates for other processes.

  • 14.
    Eilers, Gerriet
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Zettersten, Camilla
    Nyholm, Leif
    Hammarström, Leif
    Lomoth, Reiner
    Ligand exchange upon oxidation of a dinuclear Mn complex - Detection of structural changes by FT-IR spectroscopy and ESI-MS.2005In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, no 6, p. 1033-1041Article in journal (Refereed)
  • 15. Enander, Karin
    et al.
    Aili, D.
    Baltzer, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Lundström, I.
    Liedberg, B.
    Alpha helix-inducing dimerization of synthetic polypeptide scaffolds on gold2005In: Langmuir, no 21, p. 2480-2487Article in journal (Refereed)
  • 16. Eriksson, Per
    et al.
    Engman, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Lind, Johan
    Merényi, Gabor
    Aqueous Phase One-Electron Reduction of Sulfonium, Selenonium and Telluronium Salts2005In: Eur. J. Org. Chem., p. 701-705Article in journal (Refereed)
    Abstract [en]

    Triorganylsulfonium, -selenonium and -telluronium salts were reduced by carbon dioxide radical anions/solvated electrons produced in aqueous solution by radiolysis. The radical expulsion accompanying reduction occurred with the expected leaving group propensities (benzyl > secondary alkyl> primary alkyl> methy> phenyl), although greater than expected loss of the phenyl group was often observed. Diorganyl chalcogenides formed in the reductions were conveniently isolated by extraction with an organic solvent. Product yields based on the amount of reducing radicals obtained from the y-source were often higher than stoichiometric (up to 1800%) in the reduction of selenonium an dtelluronium compounds; it is likely that this result can be accounted for in terms of a chain reaction with carbon-centred radicals/formate serving as the chain transfer agent. The product distribution was essentially independent of the reducing species for diphenyl alkyl telluronium salts, whereas significant variations were seen for some of the corresponding selenonium salts. This would suggest the intermediacy of telluranyl radicals in the one-electron reduction of telluronium salts. However, pulse radiolysis experiments indicated that the lifetimes of such a species (the triphenyltelluranyl radical) would have to be less than 1 us.

  • 17. Fryxelius, Jacob
    et al.
    Eilers, Gerriet
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Feyziyev, Yashar
    Magnuson, Ann
    Sun, Licheng
    Lomoth, Reiner
    Synthesis and redox properties of a [meso-tris(4-nitrophenyl) corrolato]Mn(III) complex.2005In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, no 9(6), p. 379-386Article in journal (Refereed)
  • 18.
    Gayet, Arnaud
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Organic Chemistry.
    Development of New Chiral Bicyclic Ligands: Applications in Catalytic Asymmetric Transfer Hydrogenation, Epoxidations, and Epoxide Rearrangements2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes the synthesis and application of new chiral bicyclic ligands and their application in asymmetric catalysis. The studies involved: [i] The development of novel chiral bicyclic amino sulfur ligands and their use in transfer hydrogenation. [ii] The development of the kinetic resolution of racemic epoxide through the use of chiral lithium amides. [iii] The synthesis and application of chiral bicyclic amine in the organocatalysed epoxidation of alkenes. [iv] Development and application of new chiral diamine ligands in the rearrangement of epoxides into allylic alcohols.

    [i] The preparation of two-series of amino thiol ligands based on the structure of camphor is described, together with their application in the iridium-catalysed asymmetric transfer hydrogenation of acetophenone using isopropanol as the hydrogen source. Excellent activity and good enantioselectivity have been achieved using 2 mol% of chiral ligand in combination with [IrCl(COD)]2.

    [ii] The chiral diamines (1S,3R,4R)-3-(pyrrolidine-1-ylmethyl)-2-aza-bicyclo[2.2.1]heptane and its (2R,5R)-dimethylpyrrolidine derivative were applied to the kinetic resolution of a variety of racemic 5-7 membered cycloalkene oxides with lithium diisopropylamide (LDA) as the bulk base. Using 5 mol% of the chiral diamines, both unreacted epoxides and allylic alcohols could be produced in enantiomeric excess up to 99%.

    [iii] The synthesis of chiral bicyclic amines and their use in the organocatalysed epoxidation of alkene has been described. Using a substoichiometric amount of the chiral amines and aldehydes as ligands precursors, with Oxone® as oxidant, a good activity but moderate enantioselectivity was observed for the epoxidation of trans-stilbene.

    [iv] The preparation of 6-substituted-7-bromo-aza-bicyclo[2.2.1]heptanes via nucleophilic addition of organocopper reagents to 3-bromo-1-azoniatricyclo[2.2.1.0]heptyle bromide has been described. These compounds have been utilised as chiral building blocks in the preparation of novel chiral diamine ligands, which have been successfully applied to the catalysed asymmetric rearrangement of epoxide into the corresponding allylic alcohol.

    List of papers
    1. Novel Catalytic Kinetic Resolution Of Racemic Epoxides to Allylic alcohols
    Open this publication in new window or tab >>Novel Catalytic Kinetic Resolution Of Racemic Epoxides to Allylic alcohols
    2002 In: Organic Letters, ISSN 1523-7060, Vol. 4, no 22, p. 3777-3779Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92519 (URN)
    Available from: 2005-01-10 Created: 2005-01-10Bibliographically approved
    2. Development of new camphor based N,S chiral ligands and their application in transfer hydrogenation
    Open this publication in new window or tab >>Development of new camphor based N,S chiral ligands and their application in transfer hydrogenation
    2004 In: Organic & Biomolecular Chemistry, ISSN 1477-0520, Vol. 2, no 13, p. 1887-1893Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92520 (URN)
    Available from: 2005-01-10 Created: 2005-01-10Bibliographically approved
    3. Synthesis of 6-Substituted 7-Bomoazabicyclo[2.2.1]heptanes via Nucleophilic Addition to 3-Bromo-1-azoniatricyclo[2.2.1.0]-heptane Bromide
    Open this publication in new window or tab >>Synthesis of 6-Substituted 7-Bomoazabicyclo[2.2.1]heptanes via Nucleophilic Addition to 3-Bromo-1-azoniatricyclo[2.2.1.0]-heptane Bromide
    2005 (English)In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 347, no 9, p. 1242-1246Article in journal (Refereed) Published
    Abstract [en]

    We describe herein an efficient method for the preparation of a functionalised bicyclic framework (6-substituted 7-bromo-aza-bicyclo[2.2.1]heptane) through the selective opening of the aziridium 2 with organocuprates in up to 90% yield. These interesting chiral building blocks were then utilised as novel ligands in the rearrangement of epoxides to afford chiral allylic alcohols.

    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-92521 (URN)10.1002/adsc.200404322 (DOI)
    Available from: 2005-01-10 Created: 2005-01-10 Last updated: 2017-12-14Bibliographically approved
  • 19.
    Gayet, Arnaud
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Kinetic resolution of racemic epoxides using a chiral diamine catalyst2005In: Tetrahedron Letters, no 46, p. 4805-4807Article in journal (Refereed)
  • 20.
    Gayet, Arnaud
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Synthesis of 6-Substituted 7-Bomoazabicyclo[2.2.1]heptanes via Nucleophilic Addition to 3-Bromo-1-azoniatricyclo[2.2.1.0]-heptane Bromide2005In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 347, no 9, p. 1242-1246Article in journal (Refereed)
    Abstract [en]

    We describe herein an efficient method for the preparation of a functionalised bicyclic framework (6-substituted 7-bromo-aza-bicyclo[2.2.1]heptane) through the selective opening of the aziridium 2 with organocuprates in up to 90% yield. These interesting chiral building blocks were then utilised as novel ligands in the rearrangement of epoxides to afford chiral allylic alcohols.

  • 21.
    Ghirmai, Senait
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Mume, Eskender
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Lundqvist, Hans
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Sjöberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Synthesis and radioiodination of some 9-aminoacridine derivatives for potential use in radionuclide therapy2005In: Journal of labelled compounds & radiopharmaceuticals, ISSN 0362-4803, E-ISSN 1099-1344, Vol. 48, no 12, p. 855-871Article in journal (Refereed)
  • 22.
    Ghirmai, Senait
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Mume, Eskender
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Tolmachev, Vladimir
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Sjöberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Synthesis and radioiodination of some daunorubicin and doxorubicin derivatives2005In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 340, no 1, p. 15-24Article in journal (Refereed)
    Abstract [en]

    Daunorubicin and doxorubicin are efficient agents for cancer treatment. Their clinical efficacy is, however, hampered by their indiscriminant toxicity. This problem may be circumvented by encapsulating the drugs in liposomes and selectively targeting the tumor cells using tumor targeting agents. Furthermore, the antitumor effect could be enhanced by attaching the Auger electron emitter, 125I, to daunorubicin an ddoxorubicin derivatives. In this context a number of ester, amide, and amine derivatives of daunorubicin an ddoxorubicin were synthesized. Benzoic acid ester derivatives of daunorubicin were synthesized by nucleophilic esterification of the 14-bromodaunorubicin with the potassium salt of the corresponding benzoic acid, resulting in good yields. Nicotinic acids and benzoic acids, activated with a succinimidyl group, were coupled to the amino group of daunorubicien to give the corresponding amide derivatives. Amine derivatives were obtained by the reductive amination of aromatic aldehydes with daunorubicin hydrochloride. The stannylated ester and amide derivatives were uses as precursors for radioiodination. Radiolabeling with 125I was performed using chloroamine-T as an oxidant. The optimized labeling resulted in high radiolabeling yields (85-95%) of the radioiodinated daunorubicin and doxorubicin derivatives. Radioiodination of the amines was conducted at the ortho position of the activated phenyl rings providing moderate radiochemical yields (55-75%).

  • 23.
    Gogoll, Adolf
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Toom, Lauri
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Grennberg, Helena
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Ligand-Induced Formation of an Adamantanoid Hexanuclear (π-Allyl) PdII(μ3-Hydroxo) Cluster Stacked as Hydrogen-Bonded Double Strands2005In: Angew. Chem. Int. Ed., no 44, p. 2295-2300Article in journal (Refereed)
  • 24. Gogoll, Adolf
    et al.
    Toom, Lauri
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Grennberg, Helena
    Ligand-Induced Formation of an Adamantanoid Hexanuclear (π-Allyl)PdII(μ3-Hydroxo) Cluster Stacked as Hydrogen-Bonded Double Strands2005In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 44, no 30, p. 4729-4731Article in journal (Refereed)
  • 25.
    Hedberg, Christian
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Design, Synthesis, Mechanistic Rationalization and Application of Asymmetric Transition-Metal Catalysts2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes mechanistic studies, rational ligand design, and synthesis of asymmetric transition metal catalysts. The topics addressed concerned [Papers I-VII]:

    [I] The asymmetric addition of diethyl zinc to N-(diphenylphosphinoyl)benzalimine catalyzed by bicyclic 2-azanorbornyl-3-methanols was studied. An efficient route to both diastereomers of new bicyclic 2-azanorbornyl-3-methanols with an additional chiral center was developed, in the best case 97% ee was obtained with these ligands. The experimental results were rationalized by a computational DFT-study.

    [II] An aza-Diels-Alder reaction of cyclopentadiene with chiral heterocyclic imines derived from (S)-1-phenylethylamine and different heteroaromatic aldehydes was developed. The cycloaddition proved to be highly diastereoselective and offers a very rapid access to possible biologically active compounds and interesting precursors for chiral (P,N)-ligands.

    [III] A convenient and high-yielding method for the preparation of (R)-tolterodine, utilizing a catalytic asymmetric Me-CBS reduction was developed. Highly enantio-enriched (R)-6-methyl-4-phenyl-3,4-dihydrochromen-2-one (94% ee) was recrystallized to yield practically enantiopure material (ee >99%) and converted to (R)-tolterodine in a four-step procedure.

    [IV] The reaction mechanism of the iridium-phosphanooxazoline-catalyzed hydrogenation of unfunctionalized olefins has been studied by means of DFT-calculations (B3LYP) and kinetic experiments. The calculations suggest that the reaction involves an unexpected IrIII-IrV catalytic cycle facilitated by coordination of a second equivalent of dihydrogen. On the basis of the proposed catalytic cycle, calculations were performed on a full system with 88 atoms. These calculations were also used to explain the enantioselectivity displayed by the catalyst.

    [V and VI] A new class of chiral (P,N)-ligands for the Ir-catalyzed asymmetric hydrogenation of aryl alkenes was developed. These new ligands proved to be highly efficient and tolerate a broad range of substrates. The enantiomeric excesses are, so far, the best reported and can be rationalized using the proposed selectivity model.

    [VII] The complex formed between the quincorine-amine, containing both a primary and a quinuclidine amino function, and [Cp*RuCl]4 catalyzes the hydrogenation of aromatic and aliphatic ketones in up to 90% ee approx. 24-times faster than previously reported Ru-diamine complexes. The reason for the lower but opposite stereoselectivity seen with the quincoridine-amine, as compared to the quincorine-amine, was rationalized by a kinetic and computational study of the mechanism. The theoretical calculations also revealed a significantly lower activation barrier for the alcohol mediated split of dihydrogen, as compared to the non-alchol mediated process. A finding of importance also for the diphosphine/diamine mediated enantioselective hydrogenation of ketones.

    List of papers
    1. A Theoretical and Experimental Study of the Asymmetric Addition of Dialkylzinc to N-(diphenylphosphinoyl)benzalimine
    Open this publication in new window or tab >>A Theoretical and Experimental Study of the Asymmetric Addition of Dialkylzinc to N-(diphenylphosphinoyl)benzalimine
    Show others...
    1999 In: Chemistry-A European Journal, ISSN 0947-6539, Vol. 5, no 6, p. 1692-1699Article in journal (Refereed) Published
    Abstract
    Identifiers
    urn:nbn:se:uu:diva-92875 (URN)
    Available from: 2005-04-07 Created: 2005-04-07 Last updated: 2016-08-17Bibliographically approved
    2. Diels-Alder Reaction of Heterocyclic Imine Dienophiles
    Open this publication in new window or tab >>Diels-Alder Reaction of Heterocyclic Imine Dienophiles
    2000 In: Journal of Organic Chemistry, ISSN 0022-3263, Vol. 65, no 9, p. 2810-2812Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92876 (URN)
    Available from: 2005-04-07 Created: 2005-04-07Bibliographically approved
    3. Catalytic Asymmetric Total Synthesis of Muscarinic Receptor Antagonist (R)-Tolterodine
    Open this publication in new window or tab >>Catalytic Asymmetric Total Synthesis of Muscarinic Receptor Antagonist (R)-Tolterodine
    2005 (English)In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 347, no 5, p. 662-666Article in journal (Refereed) Published
    Abstract [en]

    A convenient and high yielding method for the preparation of (R)-tolterodine, utilizing a catalytic asymmetric Me-CBS reduction was developed. Highly enantioenriched (R)-6-methyl-4-phenyl-3,4-dihydrochromen-2-one (94% ee) was recrystallized to yield practically enantiopure material (ee >99%) and converted to (R)-tolterodine in a four-step procedure. The configuration of the crucial stereocenter was preserved during the synthesis and the obtained product was identified by chiral HPLC to be the (R)-tolterodine enantiomer.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-92877 (URN)10.1002/adsc.200404234 (DOI)
    Available from: 2005-04-07 Created: 2005-04-07 Last updated: 2017-12-14Bibliographically approved
    4. New Mechanistic Insights into the Iridium-Phosphanooxazoline Catalyzed Hydrogenation of Unfunctionalized Olefins: A DFT and Kinetic Study
    Open this publication in new window or tab >>New Mechanistic Insights into the Iridium-Phosphanooxazoline Catalyzed Hydrogenation of Unfunctionalized Olefins: A DFT and Kinetic Study
    2003 In: Chemistry-A European Journal, ISSN 0022-3263, Vol. 9, no 1, p. 339-347Article in journal (Refereed) Published
    Abstract
    Identifiers
    urn:nbn:se:uu:diva-92878 (URN)
    Available from: 2005-04-07 Created: 2005-04-07 Last updated: 2016-08-17Bibliographically approved
    5. Rationally Designed Ligands for Asymmetric Iridium-Catalyzed Hydrogenation of Olefins
    Open this publication in new window or tab >>Rationally Designed Ligands for Asymmetric Iridium-Catalyzed Hydrogenation of Olefins
    Show others...
    2004 In: Journal of the American Chemical Society, ISSN 0002-7863, Vol. 126, no 44, p. 14308-14309Article in journal (Refereed) Published
    Abstract
    Identifiers
    urn:nbn:se:uu:diva-92879 (URN)
    Available from: 2005-04-07 Created: 2005-04-07 Last updated: 2016-08-17Bibliographically approved
    6. Origin of Enantioselectivity in Ir-Catalyzed Asymmetric Hydrogenation of Tri-Substituted Olefins
    Open this publication in new window or tab >>Origin of Enantioselectivity in Ir-Catalyzed Asymmetric Hydrogenation of Tri-Substituted Olefins
    Show others...
    Manuscript (Other academic)
    Abstract
    Identifiers
    urn:nbn:se:uu:diva-92880 (URN)
    Available from: 2005-04-07 Created: 2005-04-07 Last updated: 2016-08-17Bibliographically approved
    7. Mechanistic Insights into the Phosphine free RuCp*-Diamine Catalyzed Hydrogenation of Arylketones: An Experimental and Theoretical Study
    Open this publication in new window or tab >>Mechanistic Insights into the Phosphine free RuCp*-Diamine Catalyzed Hydrogenation of Arylketones: An Experimental and Theoretical Study
    Show others...
    In: Journal of the American Chemical Society, ISSN 0002-7863Article in journal (Refereed) Submitted
    Abstract
    Identifiers
    urn:nbn:se:uu:diva-92881 (URN)
    Available from: 2005-04-07 Created: 2005-04-07 Last updated: 2016-08-17Bibliographically approved
  • 26. Hedberg, Christian
    et al.
    Källström, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Arvidsson, Per
    Andersson, Pher
    Brandt, Peter
    Mechanistic Insights into the Phosphine free RuCp*-Diamine Catalyzed Hy-drogenation of Arylketones: Experimental and Theoretical Evidence for an Alcohol-Mediated Dihydrogen Activation2005In: Journal of the American Chemical Society, ISSN 0002-7863, Vol. 127, no 43, p. 15083-15090Article in journal (Refereed)
    Abstract
  • 27.
    Hedberg, Christian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Källström, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Arvidsson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Brandt, Peter
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Mechanistic Insights into the Phosphine-Free RuCp*-Diamine-Catalyzed Hydrogenation of Aryl Ketones: Experimental and Theoretical Evidence for an Alcohol-Mediated Dihydrogen Activation2005In: J. Am. Chem. Soc., no 127, p. 15083-15090Article in journal (Refereed)
    Abstract
  • 28.
    Holmberg, Pär
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Karlsson, John
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Enzymatic Kinetic Resolution of 1-(3-furyl)-3-buten-1ol2005In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 16, p. 2397-2399Article in journal (Other academic)
    Abstract [en]

    The enzymatic kinetic resolution of 1-(3-furyl)-3-buten-1-ol was investigated via the enantioselective hydrolysis of the corresponding acetate. Pseudomonas fluorescens (Fluka) was found to give the highest enantiomeric ratios of the 11 lipases screened. At 51% conversion, the ee value (eep) for the product was found to be 89%, giving an enantiomeric ratio (Ep) of 58, while the ee value (ees) for the substrate was 89%, giving an enantiomeric ratio (Ep) of 38.

  • 29.
    Isaac, Giorgis
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Analytical Chemistry.
    Development of Enhanced Analytical Methodology for Lipid Analysis from Sampling to Detection: A Targeted Lipidomics Approach2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis covers a wide range of analytical method development for lipid analysis in complex biological samples; from sample preparation using pressurized fluid extraction (PFE) and separation with reversed phase capillary liquid chromatography (RP-LC) to detection by electrospray ionization mass spectrometry (ESI/MS) and tandem MS.

    The requirements for fast, reliable and selective extraction methods with minimal usage of solvents have accelerated the development of new extraction techniques. PFE is one of the new automated, fast and efficient liquid extraction techniques which use elevated temperature and pressure with standard liquid solvents. In this thesis the reliability and efficiency of the PFE technique was investigated for the extraction of total lipid content from cod, herring muscle and human brain tissue as well as for pesticides from fatty foodstuffs. Improved or comparable efficiencies were achieved with reduced time and solvent consumption as compared to traditional methods.

    A RP-LC coupled online to ESI/MS for the analysis of phosphatidylcholine (PC) and sphingomyelin (SM) molecular species was developed and used for the analysis of brain lipids from eight groups of mice treated with vehicle and various neuroleptics. The effect of postnatal iron administration in lipid composition and behavior was investigated. Whether or not these effects could be altered by subchronic administration of the neuroleptics (clozapine and haloperidol) were examined. The results support the hypothesis that an association between psychiatric disorders, behavior abnormalities and lipid membrane constitution in the brain exists.

    Finally, a tandem MS precursor ion scan was used to analyze the developmental profile of brain sulfatide accumulation in arylsulfatase A (ASA) deficient (ASA -/-) as compared to wild type control (ASA +/+) mice. The ASA -/- mice were developed as a model of the monogenic disease metachromatic leukodystrophy with an established deficiency of the lysosomal enzyme ASA. The results showed that an alteration in the composition of sulfatide molecular species was observed between the ASA -/- and ASA +/+ mice.

    This thesis shows that modern analytical methods can provide new insights in the extraction and analysis of lipids from complex biological samples.

    List of papers
    1. Total Lipid Extraction of Homogenized and Intact Lean Fish Muscles Using Pressurized Fluid Extraction and Batch Extraction Technique
    Open this publication in new window or tab >>Total Lipid Extraction of Homogenized and Intact Lean Fish Muscles Using Pressurized Fluid Extraction and Batch Extraction Technique
    Show others...
    2005 (English)In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 53, no 14, p. 5506-5512Article in journal (Refereed) Published
    Abstract [en]

    The reliability and efficiency of pressurized fluid extraction (PFE) technique for the extraction of total lipid content from cod and the effect of sample treatment on the extraction efficiency have been evaluated. The results were compared with two liquid-liquid extraction methods, traditional and modified methods according to Jensen. Optimum conditions were found to be with 2-propanol/n-hexane (65:35, v/v) as a first and n-hexane/diethyl ether (90:10, v/v) as a second solvent, 115 oC, and 10 min of static time. PFE extracts were cleaned up using the same procedure as in the methods according to Jensen. When total lipid yields obtained from homogenized cod muscle using PFE were compared yields obtained with original and modified Jensen methods, PFE gave significantly higher yields, ~10% higher (t test, P < 0.05). Infrared and NMR spectroscopy suggested that the additional material that inflates the gravimetric results is rather homogeneus and is primarily consists of phospholipid with headgroups of inositidic and/or glycosidic nature. The comparative study demonstrated that PFE is an alternative suitable technique to extract total lipid content from homogenized cod (lean fish) and herring (fat fish) muscle showing a precision comparable to that obtained with the traditional and modified Jensen methods. Despite the necessary cleanup step, PFE showed important advantages in the solvent consumption was cut by ~50% and automated extraction was possible.

    Keyword
    Lean fish, phospholipids, pressurized fluid extraction, PFE, total lipid content
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-93095 (URN)10.1021/jf0501286 (DOI)15998106 (PubMedID)
    Available from: 2005-04-29 Created: 2005-04-29 Last updated: 2017-12-14Bibliographically approved
    2. Pressurized Fluid Extraction (PFE) as an Alternative General Method for the Determination of Pesticide Residues in Rape Seed
    Open this publication in new window or tab >>Pressurized Fluid Extraction (PFE) as an Alternative General Method for the Determination of Pesticide Residues in Rape Seed
    Show others...
    2002 In: The Analyst, ISSN 0003-2654, Vol. 127, no 4, p. 554-559Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93096 (URN)
    Available from: 2005-04-29 Created: 2005-04-29Bibliographically approved
    3. Analysis of Phosphatidylcholine and Sphingomyelin Molecular Species From Brain Extracts Using Capillary Liquid Chromatography Electrospray Ionization Mass Spectrometry
    Open this publication in new window or tab >>Analysis of Phosphatidylcholine and Sphingomyelin Molecular Species From Brain Extracts Using Capillary Liquid Chromatography Electrospray Ionization Mass Spectrometry
    Show others...
    2003 In: Journal of Neuroscience Methods, ISSN 0165-0270, Vol. 128, no 1-2, p. 111-119Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93097 (URN)
    Available from: 2005-04-29 Created: 2005-04-29 Last updated: 2011-03-21
    4. Brain Lipid Composition in Postnatal Iron-Induced Motor Behavior Alterations Following Chronic Neuroleptic Administration in Mice
    Open this publication in new window or tab >>Brain Lipid Composition in Postnatal Iron-Induced Motor Behavior Alterations Following Chronic Neuroleptic Administration in Mice
    Show others...
    In: Neuroscience LettersArticle in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-93098 (URN)
    Available from: 2005-04-29 Created: 2005-04-29 Last updated: 2011-03-21
    5. Characterization of Brain Sulfatide Molecular Species in Arylsulfatase A Deficient Mice Using Electrospray Ionization Tandem Mass Spectrometry
    Open this publication in new window or tab >>Characterization of Brain Sulfatide Molecular Species in Arylsulfatase A Deficient Mice Using Electrospray Ionization Tandem Mass Spectrometry
    Show others...
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93099 (URN)
    Available from: 2005-04-29 Created: 2005-04-29 Last updated: 2011-03-21
  • 30.
    Isaac, Giorgis
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Waldebäck, Monica
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Eriksson, Ulla
    Odham, Göran
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Total Lipid Extraction of Homogenized and Intact Lean Fish Muscles Using Pressurized Fluid Extraction and Batch Extraction Technique2005In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 53, no 14, p. 5506-5512Article in journal (Refereed)
    Abstract [en]

    The reliability and efficiency of pressurized fluid extraction (PFE) technique for the extraction of total lipid content from cod and the effect of sample treatment on the extraction efficiency have been evaluated. The results were compared with two liquid-liquid extraction methods, traditional and modified methods according to Jensen. Optimum conditions were found to be with 2-propanol/n-hexane (65:35, v/v) as a first and n-hexane/diethyl ether (90:10, v/v) as a second solvent, 115 oC, and 10 min of static time. PFE extracts were cleaned up using the same procedure as in the methods according to Jensen. When total lipid yields obtained from homogenized cod muscle using PFE were compared yields obtained with original and modified Jensen methods, PFE gave significantly higher yields, ~10% higher (t test, P < 0.05). Infrared and NMR spectroscopy suggested that the additional material that inflates the gravimetric results is rather homogeneus and is primarily consists of phospholipid with headgroups of inositidic and/or glycosidic nature. The comparative study demonstrated that PFE is an alternative suitable technique to extract total lipid content from homogenized cod (lean fish) and herring (fat fish) muscle showing a precision comparable to that obtained with the traditional and modified Jensen methods. Despite the necessary cleanup step, PFE showed important advantages in the solvent consumption was cut by ~50% and automated extraction was possible.

  • 31.
    Itsenko, Oleksiy
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Photoinitiated Radical Carbonylation Using [11C]Carbon Monoxide: 11C-Labelling of Aliphatic Carboxylic Acids, Esters, and Amides2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One-step photoinitiated free radical carbonylation was employed for the rapid (5–7 min) labelling of aliphatic carboxylic acids, esters, and amides with a short-lived positron emitter 11C (t½ = 20.3 min) at the carbonyl position. The labelled compounds were synthesized from alkyl iodides (0.05–0.1 mmol), [11C]carbon monoxide, and appropriate nucleophiles. Decay-corrected radiochemical yields were up to 74%; conversion of [11C]carbon monoxide reached 85–90%; specific radioactivity was 158–192 GBq/mmol. The labelled compounds were identified and characterized using HPLC, LC-MS, and 1H and 13C NMR. The effects of solvents, additives, photoirradiation, temperature, and reaction time were studied and discussed.

    [carbonyl-11C]Amides were synthesized using amines in 1–2 equiv. to iodides, exploiting solvent effects to control reactivity. [carboxyl-11C]Acids were synthesized using water as a nucleophile, in binary and ternary aqueous solvent mixtures; the addition of TBAOH or KOH was necessary to obtain high radiochemical yields. [carbonyl-11C]Esters were synthesized using primary and secondary alcohols, tert-butanol, and phenol. Bases were KOH, BuLi, LiHDMS.

    The effects of photosensitizers were studied and exploited to accelerate the labelling of carboxylic acids and esters resulting in 75–85% decay-corrected radiochemical yields under mild conditions without the use of bases.

    A mild procedure for the 11C-carboxylation of alkyl iodides using DMSO as an oxygen nucleophile was developed. This method is expected to be suitable in the macroscale synthesis of carboxylic acids using isotopically unmodified carbon monoxide.

    Radical carbonylation was applied to improve the synthesis of an extensively used PET tracer, [carbonyl-11C]WAY-100635. The tracer was synthesized in one step, whereas a common approach via Grignard reagents requires three steps.

    In addition, several (13C)compounds were synthesised using the described methods.

    Free radical carbonylation may be used for the 11C-carbonylation of alkyl iodides, whereas transition-metal carbonylation – of aryl halides and triflates. Thus, the two carbonylation methods are complementary with respect to the scope of synthetic targets.

    List of papers
    1. Photoinitiated Carbonylation with [11C]Carbon Monoxide Using Amines and Alkyl Iodides
    Open this publication in new window or tab >>Photoinitiated Carbonylation with [11C]Carbon Monoxide Using Amines and Alkyl Iodides
    2004 In: Journal of Organic Chemistry, ISSN 0022-3263, Vol. 69, no 13, p. 4356-4360Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93628 (URN)
    Available from: 2005-10-27 Created: 2005-10-27Bibliographically approved
    2. Radical-Mediated Carboxylation of Alkyl Iodides with [11C]Carbon Monoxide in Solvent Mixtures
    Open this publication in new window or tab >>Radical-Mediated Carboxylation of Alkyl Iodides with [11C]Carbon Monoxide in Solvent Mixtures
    2005 In: Journal of Organic Chemistry, ISSN 0022-3263, Vol. 70, no 6, p. 2244 - 2249Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93629 (URN)
    Available from: 2005-10-27 Created: 2005-10-27Bibliographically approved
    3. Synthesis of Aliphatic [carbonyl-11C]Esters Using [11C]Carbon Monoxide
    Open this publication in new window or tab >>Synthesis of Aliphatic [carbonyl-11C]Esters Using [11C]Carbon Monoxide
    2005 In: European Journal of Organic Chemistry, ISSN 1434-193X, no 17, p. 3830 - 3834Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93630 (URN)
    Available from: 2005-10-27 Created: 2005-10-27Bibliographically approved
    4. Photoinitiated Free Radical Carbonylation Enhanced by Photosensitizers
    Open this publication in new window or tab >>Photoinitiated Free Radical Carbonylation Enhanced by Photosensitizers
    2005 In: Organic Letters, ISSN 1523-7060, Vol. 7, no 21, p. 4661-4664Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93631 (URN)
    Available from: 2005-10-27 Created: 2005-10-27Bibliographically approved
    5. Carboxylation of Alkyl Iodides with [11C] and (13C)Carbon Monoxide: Using Sulfoxides as Oxygen Nucleophiles
    Open this publication in new window or tab >>Carboxylation of Alkyl Iodides with [11C] and (13C)Carbon Monoxide: Using Sulfoxides as Oxygen Nucleophiles
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93632 (URN)
    Available from: 2005-10-27 Created: 2005-10-27 Last updated: 2010-01-13Bibliographically approved
    6. The Synthesis of [carbonyl -11C]WAY-100635 and Two Analogues Using [11C]Carbon Monoxide
    Open this publication in new window or tab >>The Synthesis of [carbonyl -11C]WAY-100635 and Two Analogues Using [11C]Carbon Monoxide
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93633 (URN)
    Available from: 2005-10-27 Created: 2005-10-27 Last updated: 2010-01-13Bibliographically approved
    7. Microscale High-pressure Photochemical Reactor Apparatus
    Open this publication in new window or tab >>Microscale High-pressure Photochemical Reactor Apparatus
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93634 (URN)
    Available from: 2005-10-27 Created: 2005-10-27 Last updated: 2010-01-13Bibliographically approved
  • 32.
    Itsenko, Oleksiy
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Kihlberg, Tor
    Långström, Bengt
    Synthesis of Aliphatic [carbonyl-11C]Esters Using [11C]Carbon Monoxide2005In: European Journal of Organic Chemistry, ISSN 1434-193X, no 17, p. 3830 - 3834Article in journal (Refereed)
  • 33.
    Itsenko, Oleksiy
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    Långström, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    Photoinitiaed Free Radical Carbonylation Enhanced by Photosensitizers2005In: Organic Letters, Vol. 7, no 21, p. 4661-4664Article in journal (Refereed)
    Abstract [en]

    The enchanicing effect of several photsensitizers in photoinitiated radical carbonylation is demonstrated and applied to acceleate the synthesis of compounds labeled with short-lived 11C. With the sensitizers, the synthesis of [carbonyl-11C]esters and acids from alkyl iodides, [11C]carbon monoxides, alcohols, and water provided up to 75-85% decay-corrected radiochemical yields in 6-min reactions under mild conditions. Acetone was used as a sensitier in preparing 13C-substituted 1,10-decanedicarboxylic acid from (13C)carbon monoxide.

  • 34.
    Itsenko, Oleksiy
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Långström, Bengt
    Photoinitiated Free Radical Carbonylation Enhanced by Photosensitizers2005In: Organic Letters, ISSN 1523-7060, Vol. 7, no 21, p. 4661-4664Article in journal (Refereed)
  • 35.
    Itsenko, Oleksiy
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Långström, Bengt
    Radical-Mediated Carboxylation of Alkyl Iodides with [11C]Carbon Monoxide in Solvent Mixtures2005In: Journal of Organic Chemistry, ISSN 0022-3263, Vol. 70, no 6, p. 2244 - 2249Article in journal (Refereed)
  • 36.
    Itsenko, Oleksiy
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    Långström, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Organisk kemi.
    Radical-Mediated Carboxylation of Alkyl iodides with [11C]Carbon Monoxide in Solvent Mixtures2005In: J. Org. Chem, no 70, p. 2244-2249Article in journal (Refereed)
    Abstract [en]

    [carboxyl-11C]Carboxylic acids were prepared from alkyl iodides via photoinitiated radical reactions using 10-8 mol of [11C]carbon monoxide in binary and ternary homogeneous solvent mixtures. Short-(isobutyric), medium-, and long-chain saturated fatty acids (heptadecanoic) were labeled with isolated decay-corrected radiochemical yields ranging from 55% to 70% in 5-7 min reactions. The conversion of [11C]carbon monoxide to products reached 80-90%. To obtain good yields in the reactions performed in water- acetonitrile and water-THF mixtures, the addition of tetrabut-ylammonium hydroxide or potassium hydroxide was essential. The carboxylation was efficient for primary and secondary alkyl iodides. The carboxylation of tertiary iodides was feasible for 1-iodoadamantane but not for tert-butyl iodide. The dependence of the radiochemical yields on reaction time, photoirradiation conditions, and organic and inorganic additives was studied. The method provides a one-step route to [carboxyl-11C]carboxylic acids; traditional methods, in contrast, would require several steps. For example, using the devised reaction, conditions, 3.19 GBq of purified [1-11C]1,10-decanedicarboxylic acid (specific radioactivity 188 GBq/umol) was obtained within 35 min of the end of 10 uAh bombardment. (1-13C)4-Phenylbutyric acid was synthesized using (13C)-carbon monoxide for identifying the labelling position with 1H and 13C NMR.

  • 37.
    Kato, Haruhisa
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Brink, Maria
    Möllerstedt, Helene
    Piqueras, Mari Carmen
    Crespo, Raül
    Ottosson, Henrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    J. Org. Chem.2005In: J. Org. Chem., no 70, p. 9495-9504Article in journal (Refereed)
  • 38. Kullberg, E-B.
    et al.
    Stenerlöw, B.
    Ghirmait, Senait
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Lundqvist, Hans
    Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Malmström, P-U.
    Orlova, Anna
    Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Tolmachev, Vladimir
    Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Gedda, L.
    An Aminoacridine Derivative for Radionuclide Therapy: Dna-Binding Properties Studied in a Novel Cell-Free in vitro Assay2005In: Int. J. Onc., no 27, p. 1355-1360Article in journal (Refereed)
  • 39.
    Kushnir, Mark M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rockwood, Alan L
    Nelson, Gordon J
    Yue, Bingfang
    Assessing analytical specificity in quantitative analysis using tandem mass spectrometry: Assessment of analytical specificity2005In: Clinical Biochemistry, ISSN 0009-9120, Vol. 38, no 4, p. 319–327-Article in journal (Refereed)
  • 40.
    Lavén, Martin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Liquid Chromatography – Mass Spectrometry Analysis of Short-lived Tracers in Biological Matrices: Exploration of Radiotracer Chemistry as an Analytical Tool2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Liquid chromatography – mass spectrometry (LC-MS) methods were developed for the analysis of positron emission tomography (PET) radiotracers in biological matrices. Additionally, radiotracer chemistry was explored as an analytical tool for supporting LC-MS method development and imaging molecular interactions in miniaturised chemical analysis systems.

    Conventional radiodetection methods can offer high sensitivity in the analysis of radiotracers in biological matrices, although with the short half-life of PET tracers, this mass sensitivity decreases rapidly with time. This limits the time frame for analysis, and may compromise the precision and accuracy of the later measurements. Performing LC-MS analysis of the dominant stable isotope form of the tracer removes such time restrictions.

    An LC-MS/MS method was developed for determination of the tracer flumazenil in human plasma, with high inter-assay precision (RSD < 7%) and accuracy (95 – 104%). The method was applied in a multiple scan PET study where the plasma concentration spanned from 0.07 to 0.21 nM. The method removed the time restrictions associated with radiodetection methods and thus provided the opportunity of analysing a greater number of samples than would have been possible with radioanalysis.

    Furthermore, an LC-MS/MS method was developed that provided an efficient metabolic screening tool of potential PET tracers, whereby the substrates could be collected directly from 11C-labelling batches. This permitted repeated incubation experiments without the need of repeated labelling syntheses. A para-methoxy-benzamide analogue of the radiotracer WAY-100635 was thus identified as a potential tracer with improved metabolic stability. Additionally, a capillary LC-MS method was developed with rapid (0.75 min) and efficient (> 99%) on-line high flow-rate extraction for determination of metabolic stability of PET radiotracers.

    Finally, the concept of radionuclide imaging of miniaturised chemical analysis systems was demonstrated with the direct study of interactions within capillary extraction columns and microchannels moulded in a plastic CD and poly(dimethylsiloxane).

    List of papers
    1. Determination of flumazenil in human plasma by liquid chromatography - electrospray ionisation - tandem mass spectrometry
    Open this publication in new window or tab >>Determination of flumazenil in human plasma by liquid chromatography - electrospray ionisation - tandem mass spectrometry
    Show others...
    2004 In: Journal of Chromatography B, Vol. 808, p. 221-227Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92490 (URN)
    Available from: 2005-01-11 Created: 2005-01-11Bibliographically approved
    2. Analysis of microsomal metabolic stability using high-flow-rate extraction coupled to capillary liquid chromatography–mass spectrometry
    Open this publication in new window or tab >>Analysis of microsomal metabolic stability using high-flow-rate extraction coupled to capillary liquid chromatography–mass spectrometry
    2004 In: Journal of Chromatography B, Vol. 806, p. 119-126Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-92491 (URN)
    Available from: 2005-01-11 Created: 2005-01-11Bibliographically approved
    3. Determination of metabolic stability of positron emission tomography tracers by LC-ESI-MS/MS: an example in WAY-100635 and two analogues
    Open this publication in new window or tab >>Determination of metabolic stability of positron emission tomography tracers by LC-ESI-MS/MS: an example in WAY-100635 and two analogues
    In: Journal of Pharmaceutical and Biomedical AnalysisArticle in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-92492 (URN)
    Available from: 2005-01-11 Created: 2005-01-11Bibliographically approved
    4. Radionuclide Imaging of Miniaturized Chemical Analysis Systems
    Open this publication in new window or tab >>Radionuclide Imaging of Miniaturized Chemical Analysis Systems
    Show others...
    2004 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 76, no 23, p. 7102-7108Article in journal (Refereed) Published
    Abstract [en]

    We propose radionuclide imaging as a valuable tool for the study of molecular interactions in miniaturized systems for chemical analysis. Sensitive and quantitative imaging can be performed with compounds labeled with short-lived positron-emitting radionuclides, such as C-11 and Ga-68, within selected parts of the system. Radionuclide imaging is not restricted to transparent materials since the relatively energetic positrons can penetrate high optical density materials. Experimentally, a radiotracer is introduced into the object of study, which is subsequently placed on a phosphor storage plate. After exposure, the plate is scanned with a laser and a digital, quantitative image can be reconstituted. To demonstrate the concept, three types of microstructures suited for integration in chemical analysis systems were imaged with C-11- and Ga-68-labeled tracers. The influence of factors such as geometry of the object and type of radionuclide on resolution and sensitivity was investigated. The resolution ranged from 0.9 to 2.7 mm (fwhm). Measuring low amounts of radioactivity in the three structures, 2-20 Bq could be detected, which corresponded to 2.3-500 amol or 2.4-110 pM tracer. The imaging approach was applied to study analyte concentration and sample dilution effects on the performance of a capillary extraction column integrated in an automated LC-ESI-MS system. The utility of the technique was further illustrated by imaging of microchannels in a zeonor plastic compact disk and in a poly(dimethylsiloxane) material for the study of nonspecific peptide adsorption.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-92493 (URN)10.1021/ac040070e (DOI)
    Available from: 2005-01-11 Created: 2005-01-11 Last updated: 2017-12-14Bibliographically approved
    5. Imaging of peptide adsorption to microfluidic channels in a plastic compact disc using a positron emitting radionuclide
    Open this publication in new window or tab >>Imaging of peptide adsorption to microfluidic channels in a plastic compact disc using a positron emitting radionuclide
    Show others...
    In: Lab on a ChipArticle in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-92494 (URN)
    Available from: 2005-01-11 Created: 2005-01-11 Last updated: 2014-03-03Bibliographically approved
  • 41. Lavén, Martin
    et al.
    Velikyan, Irina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Djodjic, Majda
    Ljung, Jenny
    Berglund, Oskar
    Markides, Karin E
    Långström, Bengt
    Wallenborg, Susanne
    Imaging of peptide adsorption to microfluidic channels in a plastic disc using a positron emitting radionuclide2005In: Lab on a chip, Vol. 5, p. 756-763Article in journal (Refereed)
  • 42.
    Lavén, Martin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Velikyan, Irina
    Djodjic, Majda
    Ljung, Jenny
    Berglund, Oskar
    Markides, Karin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Långström, Bengt
    Wallenborg, Susanne
    Imaging of peptide adsorption to microfluidic channels in a plastic compact disc using a positron emitting radionuclide2005In: Lab Chip, no 5, p. 756-763Article in journal (Refereed)
    Abstract [en]

    A method for studying peptide-surface interactions within microfluidic channels by radionuclide imaging is described. With the high surface area-to-volume ratio of channels in miniaturised devices, combined with low amunts of analyte, non-specific peptide adsorption is a critical issue. The objective of the study was therefore to develop a method capable of direct detection of adsorbed peptide within microfluidic channels. A micro-device consisting of channels moulded in a plastic compact disc was chosen for the study, together with two selected peptides of different lengths and isolelectric point (pI) values. A bifunctional chelator, DOTA, was attached to the peptide by conjugation and labelled with the short-lived positron emitting radionuclide 68Ga. Quantitative images of radiotracer distribution within the microfluidic channels were obtained using a PhosphorImager system. The power of the method was demonstrated by the ability to clearly measure changes in adsorption when varying a number of parameters that typically affect peptide adsorption. These included surface modifications, analyte concentration, pH, and ionic strength. Additionally, two quantification methods were developed and compared. Radionuclide imaging also permitted visualisation of adsorption and release processes in microchannel chromatographic columns. The results suggest that radionuclide imaging is a suitable tool not only for the study of peptide adsorption to the microchannels presented in this study but also as a versatile tool to measure peptide-surface interactions in a wide variety of miniaturised structures and devices.

  • 43. Lendvai, Gabor
    et al.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Bergström, Mats
    Laryea, Daniel
    Välilä, Maria
    Salomäki, Satu
    Långström, Bengt
    Roivainen, Anne
    Biodistribution of 68Ga-labelled phosphodiester, phosphorothioate, and 2'-O-methyl phosphodiester oligonucleotides in normal rats2005In: European Journal of Pharmaceutical Sciences, Vol. 26, p. 26-38Article in journal (Refereed)
  • 44.
    Liljegren, Gustav
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Development and Investigations of Novel Sample Preparation Techniques: Electrochemical Extraction and Evaluation of Miniaturized Analytical Devices Coupled to Mass Spectrometry2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Different sample preparation steps prior to a detection method are often essential in analytical chemistry. In this thesis, both static extractions and on-line coupled solid-phase extractions have been studied in combination with different detection techniques. Aspects of performing sample preparations in miniaturized analytical devices and the development of poly(dimethylsiloxane) (PDMS) microchips are discussed. Polypyrrole was also evaluated as an electrochemically controllable stationary phase for solid-phase microextraction (SPME) and solid-phase extraction (SPE).

    The first part of this thesis describes the extraction of an organic compound from a very complex solid matrix utilizing the pressurized-fluid extraction (PFE) technique. The presented results show that PFE is easily optimized and enables rapid extractions and extracts relatively free from interferences.

    An integrated three-electrode device, which enabled electrochemical (EC) SPME under potential control, was developed. With this device, both anions and cations could be extracted employing two types of polypyrrole films. Planar micro band electrodes positioned at the end of a capillary were also used to electrochemically extract and detect anions in a miniaturized flow system. Different analyte concentrations and preconcentration times were examined, and good linear correlations were found between the extraction time and the detection response. The on-line coupling of a thin layer EC cell, with a polypyrrole coated working electrode, to different mass spectrometric (MS) techniques is also described and evaluated. The results show that EC-SPE, employing polypyrrole as stationary phase, can be used as a preconcentration step prior to detection.

    In addition, this thesis describes the development and on-line coupling of a microelectrode array equipped PDMS microchip with an integrated graphite electrospray emitter to electrospray ionization (ESI) MS. The system enabled short transfer times and an EC conversion efficiency of 30% at a flow rate of 0.5 μL/min. The on-line EC/ESI-MS experiments were significantly simplified using a wireless Bluetooth battery-powered EC instrument.

    List of papers
    1. Pressurized-fluid extraction of chlorinated paraffins from the biodegradable fraction of source-separated household waste
    Open this publication in new window or tab >>Pressurized-fluid extraction of chlorinated paraffins from the biodegradable fraction of source-separated household waste
    Show others...
    2001 In: Fresenius Journal of Analytical Chemistry, ISSN 0937-0633, Vol. 370, no 7, p. 913-918Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93081 (URN)
    Available from: 2005-05-03 Created: 2005-05-03Bibliographically approved
    2. Electrochemical solid-phase microextraction of anions and cations using polypyrrole coatings and an integrated three-electrode device
    Open this publication in new window or tab >>Electrochemical solid-phase microextraction of anions and cations using polypyrrole coatings and an integrated three-electrode device
    2002 In: The Analyst, ISSN 0003-2654, Vol. 127, no 5, p. 591-597Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93082 (URN)
    Available from: 2005-05-03 Created: 2005-05-03Bibliographically approved
    3. Electrochemically controlled solid-phase microextraction and preconcentration using polypyrrole coated microarray electrodes in a flow system
    Open this publication in new window or tab >>Electrochemically controlled solid-phase microextraction and preconcentration using polypyrrole coated microarray electrodes in a flow system
    2003 In: The Analyst, ISSN 0003-2654, Vol. 128, no 3, p. 232-236Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93083 (URN)
    Available from: 2005-05-03 Created: 2005-05-03Bibliographically approved
    4. Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip
    Open this publication in new window or tab >>Capillary electrophoresis coupled to mass spectrometry from a polymer modified poly(dimethylsiloxane) microchip with an integrated graphite electrospray tip
    Show others...
    2005 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 130, no 2, p. 193-199Article in journal (Refereed) Published
    Abstract [en]

    Hybrid capillary-poly(dimethysiloxane) (PDMS) microchips with integrated electrospray ionization (ESI) tips were directly fabricated by casting PDMS in a mould. The shapes of the emitter tips were drilled into the mould, which produced highly reproducible three-dimensional tips. Due to the fabrication method of the microfluidic devices, no sealing was necessary and it was possible to produce a perfect channel modified by PolyE-323, an aliphatic polyamine coating agent. A variety of different coating procedures were also evaluated for the outside of the emitter tip. Dusting graphite on a thin unpolymerised PDMS layer followed by polymerisation was proven to be the most suitable procedure. The emitter tips showed excellent electrochemical properties and durabilities. The coating of the emitter was eventually passivated, but not lost, and could be regenerated by electrochemical means. The excellent electrochemical stability was further confirmed in long term electrospray experiments, in which the emitter sprayed continuously for more than 180 h. The PolyE-323 was found suitable for systems that integrate rigid fused silica and soft PDMS technology, since it simply could be applied successfully to both materials. The spray stability was confirmed from the recording of a total ion chromatogram in which the electrospray current exhibited a relative standard deviation of 3.9% for a 30 min run. CE-ESI-MS separations of peptides were carried out within 2 min using the hybrid PDMS chip resulting in similar efficiencies as for fused silica capillaries of the same length and thus with no measurable band broadening effects, originating from the PDMS emitter.

    National Category
    Analytical Chemistry Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-93084 (URN)10.1039/b414592e (DOI)15665973 (PubMedID)
    Available from: 2005-05-03 Created: 2005-05-03 Last updated: 2017-12-14Bibliographically approved
    5. On-line electrochemically controlled solid-phase extraction coupled to electrospray and inductively coupled plasma mass spectrometry
    Open this publication in new window or tab >>On-line electrochemically controlled solid-phase extraction coupled to electrospray and inductively coupled plasma mass spectrometry
    Show others...
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93085 (URN)
    Available from: 2005-05-03 Created: 2005-05-03 Last updated: 2010-01-13Bibliographically approved
    6. On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray emitter to electrospray ionisation mass spectrometry
    Open this publication in new window or tab >>On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray emitter to electrospray ionisation mass spectrometry
    Show others...
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93086 (URN)
    Available from: 2005-05-03 Created: 2005-05-03 Last updated: 2011-03-21
  • 45.
    Liljegren, Gustav
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Dahlin, Andreas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Zettersten, Camilla
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Nyholm, Leif
    Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    On-line coupling of a microelectrode array equipped poly(dimethylsiloxane) microchip with an integrated graphite electrospray emitter for electrospray ionisation mass spectrometry2005In: Lab on a Chip, no 5, p. 1008-1016Article in journal (Refereed)
    Abstract [en]

    A novel method for the manufacturing of microchips for on-chip combinations of electrochemistry (EC) and sheathless electrospray ionisation mass spectrometry (ESI-MS) is described. The technique, which does not require access to clean-room facilities, is based on the incorporation of an array of gold microcoil electrodes into a poly(dimethylsiloxane) (PDMS) microflow channel equipped with an integrated graphite based sheathless ESI emitter. Electrochemical measurements, which were employed to determine the electroactive area of the electrodes and to test the microchips, show that the manufacturing process was reproducible and that the important interelectrode distance in the electrochemical cell could to be adequately controlled. The EC-ESI-MS device was evaluated based on the ESI-MS detection of the oxidation products of dopamine. The results demonstrate that the present on-chip approach enables full potentiostatic control of the electrochemical cell and the attainment of very short transfer times between the electrochemical cell and the electrospray emitter. The transfer times were 0.6 and 1.2 s for flow rates of 1.0 and 0.5 uL min-1, respectively, while the electrochemical conversion efficiency of the electrochemical cell was found to be 30% at a flow rate of 0.5 uL min-1. To decouple the electrochemical cell from the ESI-MS high voltage and to increase the user-friendliness, the on-line electrochemistry-ESI-MS experiments were performed using a wireless Bluetooth battery-powered instrument with the chip floating at the potential induced by the ESI high voltage. The described on-chip EC-ESI-MS device can be used for fundamental electrochemical investigations as well as for applications based on the use of electrochemically controlled sample pretreatment, preconcentration and ionisation steps prior to ESI-MS.

  • 46. Liljegren, Gustav
    et al.
    Forsgard, Niklas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Analytical Chemistry.
    Zettersten, Camilla
    Pettersson, Jean
    Svedberg, Malin
    Herranen, Merja
    Nyholm, Leif
    On-line electrochemically controlled solid-phase extraction interfaced to electrospray and inductively coupled plasma mass spectrometry2005In: The Analyst, ISSN 0003-2654, Vol. 130, no 10, p. 1358-1368Article in journal (Refereed)
  • 47.
    Liljegren, Gustav
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Forsgard, Niklas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Zettersten, Camilla
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Pettersson, Jean
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Analytisk kemi.
    Svedberg, Malin
    Herranen, Merja
    Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    Nyholm, Leif
    Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    On-line electrochemically controlled solid-phase extraction interfaced to electrospray and inductively coupled plasma mass spectrometry2005In: The Analyst, no 130, p. 1358-1368Article in journal (Refereed)
    Abstract [en]

    Electrochemically controlled solid-phase extractions of anions were interfaced on-line to electrospray mass spectrometry (ESI-MS) and inductively coupled plasma mass spectrometry (ICP-MS), using polypyrrole coated electrodes and a thin-layer electrochemical (EC) flow cell. The results indicate that electrochemically controlled solid-phase extraction (EC-SPE) can be used as a versatile potential controlled sample preparation technique for a range of anions and that the properties of the polypyrrole coatings can be modified by altering the electrodeposition conditions. In the present study, the influence of interfering anions (i.e., fluoride and sulfate), and the anion used during the electropolymerisation, on the bromide extraction recovery was investigated for EC-SPE interfaced to ICP-MS. The results of these experiments show that the interference due to the presence of similar concentrations of sulfate can be reduced when using a polypyrrole coating electropolymerised in the presence of bromide ions. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements were also used to study the morphology of the coatings, as well as the variations in the film thickness within the coatings. The effect of different desorption techniques on the bromide preconcentration factor in the ICP-MS on-line flow system was also examined. Stopped-flow desorption was found to give rise to significantly increased preconcentration factors in comparison with desorptions in flowing solutions. While the desorption efficiency depends on the type of desorption electrolyte (the electrolyte in which the desorption takes place), due to the competing influx of cations, the influence of the pH on the switching charge of the polypyrrole coating was found to be small, at constant ionic strength. To study the applicability of the EC-SPE technique with respect to real samples, investigations were also made with tap water samples spiked with different bromide concentrations. The results of these experiments, which were carried out using a modified thin-layer EC flow cell allowing in situ polymerisation of polypyrrole yielding a polymer plug covering the cross section of the channel, demonstrate that 3 uM concentrations of bromide could be detected in the tap water sample. This demonstrates that the extraction technique allows extractions of low concentrations of ions in the presence of significantly higher concentrations of other similar ions. The fact that the extraction and desorption steps are electrochemically controlled makes EC-SPE particularly well suited for inclusion in miniaturised lab-on-a-chip systems.

  • 48.
    Moberg, My
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Markides, Karin E.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Bylund, Dan
    Multi-parameter investigation of tandem mass spectrometry in a linear ion trap using response surface modelling2005In: Journal of Mass Spectrometry, no 40, p. 317-324Article in journal (Refereed)
    Abstract [en]

    The feasibility of experimental design in combination with subsequent response surface modelling was illustrated for the prediction and interpretation of tandem mass spectrometric (MS/MS) fragmentation data using a linear quadrupole ion trap under various experimental conditions. The instrumental parameters included were (i) the pressure of the collision gas, (ii) the collision energy, (iii) the fill time of the linear ion trap and (iv) the scan rate. The spectral intensity and width of five fragment ions of the doubly charged neuro-active peptide bombesin were used for evaluation, and all experiments were performed so as to resemble the results obtained from a liquid chromatographic peak. The reported results show how fairly simple mathematical tools can be utilized sucessfully to describe fundamental mechanisms associated with multiple collisional activation and collision-induced dissociation processes without an extensively controlled experimental environment. Most beneficial, using the suggested approach, is the ability to study interaction (synergistic) effects between various parameters. As we realized from the results, many interaction effects are indeed significant. For example, the effect on the signal intensity of different collision gas pressure settings is strongly dependent on the settings of the other parameters. The described approach can easily be adopted for optimization purposes of any MS/MS experiment.

  • 49.
    Modin, Judit
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Synthesis and Evaluation of Photoactive Pyridine Complexes for Electron Transfer Studies and Photoelectrochemical Applications2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, the preparation of new photoactive substances containing mono- and bipyridines coordinated to ruthenium is presented together with initial evaluations of their photoelectrochemical and photophysical properties.

    Complexes of the type Ru(bpy)2(4-X-py)2 (X = SH, COOH) were prepared and used in Grätzel-type solar cells based on ZnO. The results show that the thiol complex binds to the surface but give rather low solar cell efficiencies. Different routes to obtain Ru(bpy)2(4,4´-dithio-2,2´-bipyridine) were evaluated, among them substitution reactions on 4,4´-dichloro-2,2´-bipyridine coordinated to ruthenium. Due to reactivity issues, the target sulphur-containing complex has not yet been obtained.

    The synthesis of methanofullerenes, fulleropyrrolidines and –pyrazolines are presented, among them dyads containing Ru(bpy)n-units. A common feature for the dyads is the unusually short linkers between the fullerene and the ruthenium complex. Dyad preparations were in some cases simplified by carrying out the reactions in the presence of silver salts.

    A preliminary evaluation of the emission of the dyads showed almost complete quenching of the excited state of a pyrrolidine-based dyad, whereas emission remained from the pyrazoline-based ones. Whether this was due to incomplete quenching of the excited states of the ruthenium complex, or induced by the presence of hydrazones has yet to be revealed.

    The use of fullerene-substituted malonic acid and its ethyl ester as dyes in Grätzel-type solar cells resulted in even lower efficiencies (IPCE) than for bare TiO2. This could be due to electron transfer in the reverse direction compared to what is observed for ruthenium complexes. Thus, these fullerene derivatives are not suitable as sensitisers for Grätzel-type solar cells.

    List of papers
    1. Femtosecond Transient Absorption Anisotropy Study on [Ru(bpy)3]2+ and [Ru(bpy)(py)4]2+. Ultrafast Interligand Randomization of the MLCT State
    Open this publication in new window or tab >>Femtosecond Transient Absorption Anisotropy Study on [Ru(bpy)3]2+ and [Ru(bpy)(py)4]2+. Ultrafast Interligand Randomization of the MLCT State
    2005 In: Journal of Physical Chemistry A, ISSN 1089-5639, Vol. 109, no 21, p. 4697-4704Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93781 (URN)
    Available from: 2005-11-18 Created: 2005-11-18Bibliographically approved
    2. New dyes for solar cells based on nanostructured semiconducting metal oxides - Synthesis and characterisation of ruthenium(II) complexes with thiol-substituted ligands.
    Open this publication in new window or tab >>New dyes for solar cells based on nanostructured semiconducting metal oxides - Synthesis and characterisation of ruthenium(II) complexes with thiol-substituted ligands.
    2002 In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, Vol. 148, no 1-3, p. 41-48Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93782 (URN)
    Available from: 2005-11-18 Created: 2005-11-18 Last updated: 2011-04-06
    3. New pyrazolino- and pyrrolidino[60]fullerenes with transition-metal chelating pyridine substitutents: Synthesis and complexation to Ru(II)
    Open this publication in new window or tab >>New pyrazolino- and pyrrolidino[60]fullerenes with transition-metal chelating pyridine substitutents: Synthesis and complexation to Ru(II)
    2005 In: Organic Letters, ISSN 1523-7060, Vol. 7, no 18, p. 3977-3979Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93783 (URN)
    Available from: 2005-11-18 Created: 2005-11-18Bibliographically approved
    4. Dyads with Ru(II)(bipyridine)-based chromophores covalently attached to [60]fullerene via pyrazolino- or pyrrolidino links. Synthesis and preliminary photophysical studies.
    Open this publication in new window or tab >>Dyads with Ru(II)(bipyridine)-based chromophores covalently attached to [60]fullerene via pyrazolino- or pyrrolidino links. Synthesis and preliminary photophysical studies.
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93784 (URN)
    Available from: 2005-11-18 Created: 2005-11-18 Last updated: 2010-01-13Bibliographically approved
  • 50.
    Modin, Judit
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Johansson, Henrik
    Grennberg, Helena
    New pyrazolino- and pyrrolidino[60]fullerenes with transition-metal chelating pyridine substitutents: Synthesis and complexation to Ru(II)2005In: Organic Letters, ISSN 1523-7060, Vol. 7, no 18, p. 3977-3979Article in journal (Refereed)
12 1 - 50 of 81
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