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  • 151.
    Petersson, Erik
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Rosén, Johan
    Turner, Charlotta
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Danielsson, Rolf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Hellenäs, Karl-Erik
    Critical factors and pitfalls affecting the extraction of acrylamide from foods: An optimisation study2006In: Analytica Chimica Acta, no 557, p. 287-295Article in journal (Refereed)
  • 152.
    Petersson, Erik V.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Analysis of Acrylamide and Anthocyanins in Foods: Extraction Optimization for Challenging Analytes2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, the main concern has been to improve the reliability of different parts of the analytical workflow (Paper I, II, IV &V). Additionally, one of the resulting optimized methods was used in a real application (Paper III).

    Paper I-II concerned the extraction of acrylamide (AA) from foods. In Paper I different parameters such as sample particle size, extraction solvent, extraction time and extraction temperature were optimized, leading to a method that showed good agreement with the assigned AA levels of several proficiency test samples. Later, after the publication of the paper, the method showed good performance in a collaborative trial validation, in terms of trueness, repeatabil­ity and reproducibility figures. It was labeled “undoubtedly fit for the purpose”.

    In Paper II, it was shown that the ‘extra’ amounts of AA obtained during extraction of foods with an alkaline aqueous solution was not due to improved extractability of AA from the food matrix. Strongly alkaline conditions seemed to rather induce net formation of AA from water-soluble precursors formed during thermolysis. This phenomenon should therefore be regarded as an extraction artifact.

    Paper III was an application of the optimized method from Paper I, where it was used to study the reduction of AA in potato chips (crisps) by using pre-treatments and frying at reduced pressure. There were significant reductions in AA, down to below the limit of quantification (5 µg/kg) for the method.

    Paper IV-V concerned analysis of anthocyanins (AC) in red onion. In Paper IV, a new separation method using capillary electrophoresis was developed, and its rapidness combined with an acidic background electrolyte helped in preventing AC degradation. Furthermore, its alternative separation mechanism is a complement to that of the more commonly used liquid chromatography technique. In Paper V, simultaneous extraction and degradation of anthocyanins from red onion was studied in a static batch reactor at 110ºC. The extraction and degradation kinetics were successfully separated, and an ideal theoretical extraction curve was constructed by compensating mathematically for degradation effects, showing that more anthocyanins, 21 to 36% depending on different species, could be extracted if no degradation occurred. The results give important information about the different kinetics competing during an extraction procedure, and also show that quantitative extraction is not to recommend in the batch system used in the study.

    List of papers
    1. Critical factors and pitfalls affecting the extraction of acrylamide from foods: An optimisation study
    Open this publication in new window or tab >>Critical factors and pitfalls affecting the extraction of acrylamide from foods: An optimisation study
    Show others...
    2006 (English)In: Analytica Chimica Acta, no 557, p. 287-295Article in journal (Refereed) Published
    Keywords
    Acrylamide, Foods, Analysis, LC-MS/MS, Extraction, Optimisation, Method optimisation
    Identifiers
    urn:nbn:se:uu:diva-77761 (URN)doi:10.1016/j.aca.2005.10.014 (DOI)
    Available from: 2006-03-15 Created: 2006-03-15 Last updated: 2011-01-11
    2. Impact of extraction conditions on the content of acrylamide in model systems and food
    Open this publication in new window or tab >>Impact of extraction conditions on the content of acrylamide in model systems and food
    Show others...
    2006 (English)In: Food Additives and Contaminants, no 23(5), p. 437-445Article in journal (Refereed) Published
    Keywords
    acrylamide, 3-aminopropionamide, food model systems, analysis, extraction
    Identifiers
    urn:nbn:se:uu:diva-80656 (URN)doi:10.1080/02652030600632164 (DOI)
    Available from: 2006-05-19 Created: 2006-05-19 Last updated: 2011-01-11
    3. Acrylamide-Free Potato Chips
    Open this publication in new window or tab >>Acrylamide-Free Potato Chips
    Show others...
    (English)Manuscript (preprint) (Refereed)
    Abstract [en]

    The aim of this work was to minimize the acrylamide (AA) formation in potato chips, by decreasing precursors such as free reducing sugars and asparagine, and by reducing the Maillard reaction. Blanching and pH change by immersion in 0.25% citric acid solution were used as pretreatments. Frying at atmospheric (AP) and reduced pressure (RP) at different temperatures (150°C, 160°C and 170°C) was also assayed. The pretreatments minimized the AA content in the potato chips fried at both AP and RP (at the three different temperatures). With AP frying, AA contents ranged between 5 to 29µgkg-1, and with RP frying, AA contents were below the limit of quantification (5µgkg-1), which can be considered as AA-free potato chips. Without pretreatments, the AA content was lower at RP frying (80-267µgkg-1) than at AP frying, (87-760µgkg-1). Frying temperature influenced the AA formation, with lower amounts found at 150°C than 170ºC. In a consumer test panel evaluation, the acceptability score (scale 1-7) was better for pretreated chips fried at RP than at AP; 3.3-3.5 and 2.1-2.9, respectively. According to our results, it is recommended to the industry (in the meantime until RP is readily available) to apply the pretreatments assayed in this study and to decrease frying t° between 160-170ºC at AP for minimizing the AA content of potato chips. Previous pilots scale runs must be done and the same for the improvement in a couple of sensory attributes.

    Keywords
    Acrylamide, potato chips, pretreatments, atmospheric pressure frying, reduced pressure frying.
    Identifiers
    urn:nbn:se:uu:diva-109750 (URN)
    Available from: 2009-10-24 Created: 2009-10-24 Last updated: 2010-01-14
    4. Analysis of anthocyanins in red onion using capillary electrophoresis-time of flight-mass spectrometry
    Open this publication in new window or tab >>Analysis of anthocyanins in red onion using capillary electrophoresis-time of flight-mass spectrometry
    2008 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 29, no 12, p. 2723-2730Article in journal (Refereed) Published
    Abstract [en]

    For the first time, a capillary electrophoresis-time of flight-mass spectrometry analysis method for detecting anthocyanins in red onion was developed. The analysis method included the use of silica capillaries coated with poly-LA 313 (polycationic amine-containing polymer) and an MS-compatible volatile background electrolyte (BGE). The method was environmentally friendly and sensitive, and its rapidness combined with an acidic BGE helped in preventing anthocyanin degradation. By using high-resolution TOF-MS with prerun tuning of masses, low mass errors were achieved in the determination of conjugated anthocyanins in red onion, and a simultaneous up-front fragmentation provided confirmation of the aglycon backbone for their secure identification. Most anthocyanins (at least seven out of ten) known in red onion from the literature were found, as well as one new for this matrix.

    Keywords
    anthocyanins, capillary electrophoresis, polyamine coating, time of flight mass spectrometry, red onion
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-17596 (URN)10.1002/elps.200700692 (DOI)000257481300030 ()
    Available from: 2008-07-14 Created: 2008-07-14 Last updated: 2017-12-08Bibliographically approved
    5. Pressurized Hot Water Extraction of anthocyanins from red onion: A study on extraction and degradation rates
    Open this publication in new window or tab >>Pressurized Hot Water Extraction of anthocyanins from red onion: A study on extraction and degradation rates
    Show others...
    2010 (English)In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 663, no 1, p. 27-32Article in journal (Refereed) Published
    Abstract [en]

    Pressurized Hot Water Extraction (PHWE) is a quick, efficient and environmentally friendly technique for extractions. However, when using PHWE to extract thermally unstable analytes, extraction and degradation effects occur at the same time, and thereby compete. At first, the extraction effect dominates, but degradation effects soon take over. In this paper, extraction and degradation rates of anthocyanins from red onion were studied with experiments in a static batch reactor at 110 °C. A total extraction curve was calculated with data from the actual extraction and degradation curves, showing that more anthocyanins, 21–36% depending on the species, could be extracted if no degradation occurred, but then longer extraction times would be required than those needed to reach the peak level in the apparent extraction curves. The results give information about the different kinetic processes competing during an extraction procedure.

    Keywords
    Anthocyanins, Subcritical water extraction, Degradation, Rates, Red onion
    National Category
    Chemical Sciences
    Research subject
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-122407 (URN)10.1016/j.aca.2010.01.023 (DOI)000275580500005 ()20172092 (PubMedID)
    Available from: 2010-04-12 Created: 2010-04-12 Last updated: 2017-12-12Bibliographically approved
  • 153.
    Petersson, Erik V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Liu, Jiayin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Sjöberg, Per J.R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Danielsson, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Turner, Charlotta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Pressurized Hot Water Extraction of anthocyanins from red onion: A study on extraction and degradation rates2010In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 663, no 1, p. 27-32Article in journal (Refereed)
    Abstract [en]

    Pressurized Hot Water Extraction (PHWE) is a quick, efficient and environmentally friendly technique for extractions. However, when using PHWE to extract thermally unstable analytes, extraction and degradation effects occur at the same time, and thereby compete. At first, the extraction effect dominates, but degradation effects soon take over. In this paper, extraction and degradation rates of anthocyanins from red onion were studied with experiments in a static batch reactor at 110 °C. A total extraction curve was calculated with data from the actual extraction and degradation curves, showing that more anthocyanins, 21–36% depending on the species, could be extracted if no degradation occurred, but then longer extraction times would be required than those needed to reach the peak level in the apparent extraction curves. The results give information about the different kinetic processes competing during an extraction procedure.

  • 154.
    Petersson, Erik V.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Puerta, Angel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Turner, Charlotta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Analysis of anthocyanins in red onion using capillary electrophoresis-time of flight-mass spectrometry2008In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 29, no 12, p. 2723-2730Article in journal (Refereed)
    Abstract [en]

    For the first time, a capillary electrophoresis-time of flight-mass spectrometry analysis method for detecting anthocyanins in red onion was developed. The analysis method included the use of silica capillaries coated with poly-LA 313 (polycationic amine-containing polymer) and an MS-compatible volatile background electrolyte (BGE). The method was environmentally friendly and sensitive, and its rapidness combined with an acidic BGE helped in preventing anthocyanin degradation. By using high-resolution TOF-MS with prerun tuning of masses, low mass errors were achieved in the determination of conjugated anthocyanins in red onion, and a simultaneous up-front fragmentation provided confirmation of the aglycon backbone for their secure identification. Most anthocyanins (at least seven out of ten) known in red onion from the literature were found, as well as one new for this matrix.

  • 155.
    Petersson, Patrik
    et al.
    AstraZeneca R&D Lund, Sweden.
    Forssen, Patrik
    Department of Chemistry and Biomedical Science, Karlstad University, Sweden.
    Edström, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Samie, Farzad
    AstraZeneca Nordic Headquarters, Södertälje, Sweden.
    Tatterton, Stephen
    AstraZeneca R&D Charnwood, UK.
    Clarke, Adrian
    AstraZeneca R&D Charnwood, UK.
    Fornstedt, Torgny
    Department of Chemistry and Biomedical Science, Karlstad University, Sweden.
    Why ultra high performance liquid chromatography produces more tailing peaks than high performance liquid chromatography, why it does not matter and how it can be addressed.2011In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 39, p. 6914-21Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to demonstrate, with experiments and with computer simulations based on a firm chromatographic theory, that the wide spread perception of that the United States Pharmacopeia tailing factor must be lower than 2 (T(f)<2) is questionable when using the latest generation of LC equipment. It is shown that highly efficient LC separations like those obtained with sub-2μm porous and 2.7μm superficially porous particles (UHPLC) produce significantly higher T(f)-values than the corresponding separation based on 3μm porous particles (HPLC) when the same amount of sample is injected. Still UHPLC separations provide a better resolution to adjacent peaks. Expressions have been derived that describe how the T(f)-value changes with particle size or number of theoretical plates. Expressions have also been derived that can be used to scale the injection volume based on particle size or number of theoretical plates to maintain the T(f)-value when translating a HPLC separation to the corresponding UHPLC separation. An aspect that has been ignored in previous publications. Finally, data obtained from columns with different age/condition indicate that T(f)-values should be complemented by a peak width measure to provide a more objective quality measure.

  • 156.
    Puerta, Angel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Axén, Jakob
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Söderberg, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Novel adsorptive polyamine coating for enhanced capillary electrophoresis of basic proteins and peptides2006In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 838, no 2, p. 113-121Article in journal (Refereed)
    Abstract [en]

    In capillary electrophoresis (CE), the anionic and hydrophobic nature of the fused-silica capillary surface has long been known to present a problem in protein and peptide analysis. The use of capillary surface coating is one of the approaches to avoid the analyte-wall interactions. In this study, a new polymer, poly-LA 313, has been synthesized, physico-chemical characterized, and applied as polyamine coating for CE separations. The coating process is highly reproducible and provides fast separations of peptides and proteins in a few minutes and with high efficiency. The physically adsorbed polymer gives rise to a durable coating in the range of pH 2-10, in the presence of organic modifiers (acetonitrile and methanol) and with complex biological samples. The efficiency of the new cationic polymer was also tested performing protein and peptide separations with capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS).

  • 157.
    Puerta, Angel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Development of a CE-MS method to analyze components of the potential biomarker vascular endothelial growth factor 1652009In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 30, no 13, p. 2355-2365Article in journal (Refereed)
    Abstract [en]

    The vascular endothelial growth factor 165 (VEGF(165)) is the predominant form of the complex VEGF-A family. Its angiogenic effect is   involved in many physiological and pathological events. For this   reason, its roles as a potential biomarker and as a therapeutic drug   have been considered. Nevertheless, very little is known about the   existence of different forms of VEGF(165) arising from glycosylation  and potentially from other PTMs. This aspect is important because  different forms may differ in biological activity (therapeutic drug   application) and the pattern of the different forms can vary with   pathological changes (biomarker application). In this work a CE-MS   method to separate up to seven peaks containing, at least, 19 isoforms   of intact VEGF(165) is described. Comparison between human VEGF(165)   expressed in a glycosylating system, i.e. insect cells, and in a   non-glycosylating system, i.e. E. coli cells, has been carried out. The   method developed provides structural information (mass fingerprint)   about the different forms of VEGF(165) and after the deconvolution and   the analysis of the MS spectra, PTMs pattern of VEGF(165) including   glycosylation. and loss of amino acids at the N- and C-terminus was   identified. Glycans involved in PTMs promoting different glycoforms   observed in the CE-MS fingerprint were confirmed by MALDI-MS after   deglycosylation with peptide N-glycosidase F. This approach is a   starting point to study the role of VEGF(165) as a potential biomarker   and to perform quality control of the drug during manufacturing. To our   knowledge this is the first time that a CE-MS method for the analysis  of VEGF(165) has been developed.

  • 158. Quan, Can
    et al.
    Turner, Charlotta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Extraction of Astaxanthin from Shrimp Waste Using Pressurized Hot Ethanol2009In: Chromatographia, ISSN 0009-5893, E-ISSN 1612-1112, Vol. 70, no 1-2, p. 247-251Article in journal (Refereed)
    Abstract [en]

    An efficient and environmentally sustainable extraction method is proposed for the enrichment of a high-value pigment, astaxanthin, from   a low-value raw material, shrimp waste. Ethanol at elevated temperature and pressure was used as a "green" extraction solvent. An experimental   design approach based on central composite design was used to   investigate the dependence of pressurized liquid extraction (PLE)  operating variables (pressure, temperature, extraction time) on the  recovered astaxanthin concentration from shrimp waste. The results show   that at a 95% confidence level, the most significant PLE operating   variables were extraction temperature and time. Extraction pressure had   only a minor effect on the astaxanthin recovery in the studied   experimental conditions. The maximum astaxanthin recovery obtainable by   PLE was calculated from the chemometrics results and then appraised by   experiments. Our results show astaxanthin yields of around 24 mg kg(-1)   shrimp waste. The reproducibility of the developed PLE method is good,   showing a relative standard deviation of 3.5% (n = 6) for astaxanthin.

  • 159.
    Quan, Can
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Werner, Oskar
    Wågberg, Lars
    Turner, Charlotta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Generation of superhydrophobic paper surfaces by a rapidly expanding supercritical carbon dioxide - alkyl ketene dimer solution2009In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 49, no 1, p. 117-124Article in journal (Refereed)
    Abstract [en]

    Superhydrophobic alkyl ketene dimer (AKD) layers were successfully produced on top of untreated paper surfaces by a rapid expansion of supercritical CO2 solution (RESS) process. The new method resulted in a degree of hydrophobicity, as measured by contact angles of water droplets on AKD surfaces, dramatically higher, up to 173 degrees, compared to a conventional method consisting in melting AKD granules directly on the paper substrate, giving contact angles of around 109 degrees. Experiments were conducted to investigate the effects of varying pre-expansion pressure (100-300 bar), pre-expansion temperature   (40 and 60 degrees C) and spraying distance (10 and 50 mm) on the properties of the treated surfaces. The surfaces were analyzed regarding AKD particle size, surface morphology and hydrophobicity with the aid of scanning electron microscopy (SEM) and contact angle   measurements. The average AKD particle size after RESS processing was   between 1 and 2 mu m depending upon the experimental conditions used, being slightly smaller when using higher pre-expansion pressure and temperature as well as shorter spraying distance.

  • 160.
    Rajda, Cecilia
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Bencsik, K.
    Füvesi, Judit
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Seres, E.
    Vécsei, L.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    The norepinephrine level is decreased in the lymphocytes of long-term interferon-beta-treated multiple sclerosis patients2006In: Multiple Sclerosis, no 12, p. 265-270Article in journal (Refereed)
  • 161.
    Rajda, Cecilia
    et al.
    Department of Neurology, University of Szeged and cInstitute of Clinical Neuroscience, Department of Psychiatry and Neurochemistry, Göteborg University, Sahlgrenska University Hospital Mölndal.
    Dibó, Gyorgy
    Department of Neurology, University of Szeged.
    Vécsei, László
    Department of Neurology, University of Szeged and Neurology Research Group of the Hungarian Academy of Sciences and University of Szeged, Szeged, Hungary.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Increased dopamine content in lymphocytes from high-dose L-Dopa-treated Parkinson's disease patients2005In: Neuroimmunomodulation, ISSN 1021-7401, E-ISSN 1423-0216, Vol. 12, no 2, p. 81-84Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The intracellular (i.c.) content of dopamine and its metabolites was measured in the peripheral blood lymphocytes (PBLs) of Parkinson's disease (PD) patients and healthy controls. METHODS: Catecholamine levels of PBLs were measured using capillary electrophoresis in healthy controls and PD patients receiving different doses of L-dihydroxyphenylalanine (L-Dopa). RESULTS: Higher i.c. dopamine content was found in lymphocytes from PD patients receiving a high dose of L-Dopa (700 +/- 30 mg/day) as compared to lymphocytes from the healthy controls (p = 0.002) and from PD patients treated with a low dose of L-Dopa (400 +/- 30 mg/day) (p = 0.022). The dihydroxyphenylacetic acid to dopamine ratio was significantly lower in the high-dose L-Dopa-treated PD patients than in the controls (p = 0.013). CONCLUSIONS: These findings suggest that the dopamine content and metabolism in the peripheral lymphocytes of PD patients are influenced by L-Dopa administration. This is the first study in which a dose-related effect of L-Dopa treatment was found in lymphocytes from PD patients.

  • 162.
    Ramström, Margareta
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Proteomics of Human Cerobrospinal Fluid2007In: Proteomics of Human Body Fluids: Principles, Methods, and Applications, Chpt. 12, Humana Press Inc. , 2007, p. 269-284Chapter in book (Refereed)
  • 163.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Hagman, Charlotte
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Mitchell, Jennifer
    Derrick, Peter
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Depletion of High-Abundant Proteins in Body Fluids Prior to Liquid Chromatography Fourier Transform Ion Cyclotron Resonance Mass Spectrometry2005In: Journal of Proteome Research, ISSN 1535-3893, E-ISSN 1535-3907, Vol. 4, no 2, p. 410-416Article in journal (Refereed)
    Abstract [en]

    Today, proteomics is an exciting approach to discover potential biomarkers of different disorders. One challenge with proteomics experiments is the wide concentration range of proteins in various tissues and body fluids. The most abundant component in human body fluids, human serum albumin (HSA), is present at concentrations corresponding to approximately 50% of the total protein content in e.g., plasma and cerebrospinal fluid (CSF). If this component could be selectively removed, then the chances of observing lower-abundance component of clinical interest would be greatly improved. There are today several approaches of varying specificity available for depletion. In this study, the properties of two commercially available kits, for the removal of HSA and HSA and immunoglobulin G (lgG), respectively, were compared, and the benefits of using depletion steps prior to on-line LC-FTICR MS were evaluated. Both methods were applied on plasma and CSF. To our knowledge, these are the first results reported for CSF. Also, the combination with electrospray LC-FTICR MS is novel. The proportion of depleted HSA and lgG was estimated using global labeling markers for peptide quantification. Both depletion-methods provided a significant reduction of HSA, and the identification of lower abundant components was clearly facilitated. A higher proportion of HSA was removed using the affinity-based removal kit, and consequently more proteins could be identified using this approach.

  • 164.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hagman, Charlotte
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Tsybin, Youri O
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Håkansson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Ion Physics.
    Salehi, Albert
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Lundquist, Ingmar
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Håkanson, Rolf
    Department of Pharmacology, Institute of Physiological Sciences, Lund University.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    A novel mass spectrometric approach to the analysis of hormonal peptides in extracts of mouse pancreatic islets2003In: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 270, no 15, p. 3146-3152Article in journal (Refereed)
    Abstract [en]

    Liquid chromatography mass spectrometry (LC-MS) is a valuable tool in the analysis of proteins and peptides. The combination of LC-MS with different fragmentation methods provides sequence information on components in complex mixtures. In this work, on-line packed capillary LC electrospray ionization Fourier transform ion cyclotron resonance MS was combined with two complementary fragmentation techniques, i.e. nozzle-skimmer fragmentation and electron capture dissociation, for the determination of hormonal peptides in an acid ethanol extract of mouse pancreatic islets. The most abundant peptides, those derived from proinsulin and proglucagon, were identified by their masses and additional sequence-tag information established their identities. Interestingly, the experiments demonstrated the presence of truncated C-peptides, des-(25-29)-C-peptide and des-(27-31)-C-peptide. These novel findings clearly illustrate the potential usefulness of the described technique for on-line sequencing and characterization of peptides in tissue extracts.

  • 165.
    Ramström, Margareta
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Ivonin, Igor
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Johansson, Anders
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Neuroscience. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics.
    Askmark, Håkan
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Neuroscience. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics.
    Zubarev, Roman
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Håkansson, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Aquilonius, Sten-Magnus
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Neuroscience. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics.
    Bergquist, Jonas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Physical and Analytical Chemistry, Analytical Chemistry. Technology, Department of Engineering Sciences, Ion Physics. Analytisk kemi.
    Cerebrospinal fluid protein patterns in neurodegenerative disease revealed by liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry2004In: Proteomics, no 4, p. 4010-4018Article in journal (Refereed)
    Abstract [en]

    This study demonstrates the power of a novel proteomic approach developed for the detection and identification of biological markers in body fluids. The goal was to observe alterations in the protein patterns of cerebrospinal fluid (CSF) related to amyotrophic lateral sclerosis (ALS), a neuro-degenerative disorder with unknown etiology. In the experiments, tryptic digests of CSF from patients and healthy controls were analyzed by on-line capillary liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Typically, around 4000 peptides were detected in one such experiment, and a pattern recognition program was constructed for the data analysis to distinguish mass chromatograms from patients and controls. This strategy was evaluated comparing the peptide patterns of CSF spiked in vitro with a biomarker, with control CSF. The patterns were clearly separated and the tryptic peptides of the biomarker were successfully selected as characteristic peaks. Hence, the method was applied to compare mass chromatograms of CSF from 12 ALS-patients and 10 matched healthy controls. While no biomarker alone could be identified from the characteristic peaks, we were able to assign 4 out of 5 unknown samples correctly (i.e. 80% correctly diagnosed, 20% false-negative), and it would be 100% if we reject a possible outlier believed to be caused by an occlusion in the spinal CSF compartment. These findings are very promising, although the clinical relevance is not fully established due to the low number of unknown samples analyzed. In addition to the diagnostic potential, these results may be important steps towards understanding the neurodegenerative process.

  • 166.
    Ramström, Margareta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Palmblad, Magnus
    Jonfysik. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Markides, Karin E
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Håkansson, Per
    Jonfysik. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Analytical Chemistry.
    Protein identification in cerebrospinal fluid using packed capillary liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry2003In: Proteomics, Vol. 3, no 2, p. 184-190Article in journal (Refereed)
    Abstract [en]

    The identification and characterization of proteins in complex biological samples such as body fluids, require powerful and reliable tools. Mass spectrometry is today one of the most important methods in such research. This paper reports on the results from the first experiment where a tryptic digest of cerebrospinal fluid was analyzed applying reversed phase liquid chromatography coupled on-line to a 9.4 T Fourier transform ion cyclotron resonance mass spectrometer. In total, 70 204 peaks were detected, which originated from 16 296 isotopic clusters corresponding to 6551 unique peptide masses. From these masses, 39 proteins were identified in the sample. The amount of sample required for one experiment corresponds to 32 μL of cerebrospinal fluid.

  • 167. Ramström, Margareta
    et al.
    Zuberovic, Aida
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Grönwall, Caroline
    Department of Molecular Biotechnology, School of Biotechnology, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Hanrieder, Jörg
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Hober, Sophia
    Department of Proteomics, School of Biotechnology, AlbaNova University Center, Royal Institute of Technology (KTH), Stockholm, Sweden,.
    Development of affinity columns for the removal of high-abundance proteins in cerebrospinal fluid2009In: Biotechnology and applied biochemistry, ISSN 0885-4513, E-ISSN 1470-8744, Vol. 52, no Pt 2, p. 159-166Article in journal (Refereed)
    Abstract [en]

    Various approaches for removal of high-abundance components in body fluids are currently available. While most methods are constructed for plasma depletion, there is a need for body-fluid-specific strategies. The aim of the present study was to design an affinity matrix suitable for the depletion of high-abundance proteins in CSF (cerebrospinal fluid). Hence, molecules with specific affinity towards proteins present at high concentration in CSF were desired. Affibody molecules are specific binders of small size that have shown high stability under various conditions and are therefore good candidates for such a matrix. The protein composition in CSF resembles that in plasma. However, 20% of the proteins are brain-derived and are therefore present in higher proportions in CSF than in plasma, whereas larger plasma-derived proteins are less abundant in CSF. Therefore five high-abundance CSF proteins were chosen for the design of a CSF-specific depletion setup. Affibody molecules with specificity towards HSA (human serum albumin), IgG, transferrin and transthyretin were combined in an affinity column. In addition, polyclonal antibodies against cystatin C were coupled to chromatographic beads and packed in a separate column. Highly reproducible and efficient removal of the five target proteins was observed. The proportion of depleted proteins were estimated to be 99, 95, 74, 92 and 83% for HSA, IgG, transferrin, transthyretin and cystatin C respectively. SDS/PAGE analysis was used for monitoring and identifying proteins in native CSF, depleted CSF samples and the captured fractions. Moreover, shotgun proteomics was used for protein identification in native as well as depleted CSF and the achieved data were compared. Enhanced identification of lower-abundance components was observed in the depleted fraction, in terms of more detected peptides per protein.

  • 168. Reitzel, Kasper
    et al.
    Ahlgren, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Jensen, Henning
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Characterization of phosphorus in sequential extracts from lake sediments using P-31 nuclear magnetic resonance spectroscopy2006In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 63, no 8, p. 1686-1699Article in journal (Refereed)
    Abstract [en]

    Phosphorus (P) compounds in three different lake surface sediments were extracted by sequential P extraction and identified by P-31 nuclear magnetic resonance (P-31 NMR) spectroscopy. The extraction procedure primarily discriminates between inorganic P-binding sites but most extraction steps also contained P not reacting (nrP) with the molybdenum complex during P analyses. In all three lakes, the nrP dominated in the NaOH extracts. Nonreactive P from the dystrophic lake was dominated by potentially recalcitrant P groups such as orthophosphate monoesters, while the nrP in the two more productive lakes also contained polyphosphates, pyrophosphate, and organic P groups such as P lipids and DNA-P that may be important in remineralization and recycling to the water column. In addition, polyphosphates showed substantial dynamics in settling seston. The Humic-P pools (P associated with humic acids) showed strong signals of orthophosphate monoesters in all three lakes, which supported the assumption that P-containing humic compounds are indeed recovered in this fraction, although other organic P forms are also present. Thus, in addition to expanding the understanding of which organic P forms that are present in lake sediments, the P-31 NMR technique also demonstrated that the chemical extraction procedure may provide some quantification of recalcitrant versus labile organic P forms.

  • 169. Reitzel, Kasper
    et al.
    Ahlgren, Joakim
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry. Analytisk kemi.
    Gogoll, Adolf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Rydin, Emil
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Effects of aluminum treatment on phosphorus, carbon, and nitrogen distribution in lake sediment: A 31P NMR study2006In: Water Research, no 40, p. 647-654Article in journal (Refereed)
    Abstract [en]

    The effects of aluminum (A1) treatment on sediment composition of carbon (C), nitrogen (N) and phosphorus (P) were investigated in sediment representing pre- and post-treatment years in the Danish Lake Sönderby. 31P NMR spectroscopy analysis of EDTA-NaOH extracts revealed six functional P groups. Direct effects of the A1 treatment were reflected in the othophosphate profile revealing increased amounts of A1-P in the sediment layers representing the post-treatment period, as well as changes in organic P groups due to precipitation of phytoplankton and bacteria at the time of A1 additon. Furthermore, changes in phytoplankton community structure and lowered production due to the A1 treatment resulted in decreased concentrations of sediment organic P groups and total C. Exponential regressions were used to describe the diagensisi of C, N, and P in the sediment. From these regressions , half-life degradation times and C, N, and P burial rates were determined.

  • 170.
    Richard, Åse
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. Fasta tillståndets elektronik. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Klett, Oliver
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Strandman, Carola
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. Fasta tillståndets elektronik. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bäcklund, Ylva
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science. Fasta tillståndets elektronik. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Nyholm, L
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electronics. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Design of a Chip Based Microanalytical Fluidic System Based on Electrochemical Detection using Redox Cycling1999In: Proc Int Eng Congress and Exposition, Nashville, Tenessee, Nov 14-19, 1999, 1999Conference paper (Other academic)
  • 171.
    Römsing, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Development and Validation of Bioanalytical Methods: Application to Melatonin and Selected Anti-Infective Drugs2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes bioanalytical methods for measuring melatonin and some anti-infective drugs in biological fluids. Solid-phase extraction (SPE) or protein precipitation was used for enrichment and purification of the analytes and Liquid Chromatography (LC) was used to analyze the samples. Developed methods were validated according to international guidelines.

    Melatonin is a hormone secreted by the pineal gland with a robust circadian rhythm. Bioanalytical methods for determination of melatonin in plasma and saliva have been developed which were used for monitoring melatonin levels in volunteers and patients suffering from sleep related diseases.

    Eflornithine (DFMO) is a chiral drug used for the treatment of human African trypanosomiasis. A bioanalytical method for determination of the DFMO enantiomers in plasma, after precolumn derivatization with o-phtalaldehyde and N-acetyl-L-cystein has been developed. The method has been used to study the L- and D-DFMO pharmacokinetics, in order to investigate the possible development of an oral treatment of DFMO.

    A method for simultaneous determination of three antiretroviral drugs i.e. Lamivudine (3TC), Zidovudine (AZT) and Nevirapine (NVP) in dried blood spots (DBS) was developed. The method was used for drug determination in two subjects after receiving standard antiretroviral treatment. The method seemed well suitable for the determination of 3TC and NVP and in some extent for AZT.

    Lumefantrine (LF) is one of the active components in a new fixed drug combination recommended by the WHO as a replacement to older drugs that has lost their effect. A method for the determination of LF in DBS was developed. The method is suitable for monitoring of drug treatment in rural settings.

    Tafenoquine is a new promising antimalarial drug under development. A method for the determination of Tafenoquine in plasma and in DBS is described. The method may be useful in future clinical studies in laboratory environment as well as in rural settings.

    List of papers
    1. Determination of melatonin in human plasma with solid-phase extraction, high-performance liquid chromatography and fluorescence detection
    Open this publication in new window or tab >>Determination of melatonin in human plasma with solid-phase extraction, high-performance liquid chromatography and fluorescence detection
    2003 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 63, no 1, p. 81-88Article in journal (Refereed) Published
    Abstract [en]

    A new bioanalytical method for the determination of melatonin in plasma with high-performance liquid chromatography (HPLC) and fluorescence detection preceded by solid-phase extraction has been developed and validated. Melatonin was extracted from 3 mL plasma using a Waters Oasis HLB solid-phase extraction cartridge and the elute was evaporated to dryness and dissolved in 200 microl mobile phase; acetonitrile-phosphate buffer, 0.01 M pH 7.2 (25:75, v/v). 125 microL was injected into the HPLC system and separation was carried out on a Waters SymmetryShield RP18 column 5 microm (250 x 4.6 mm). Excitation and emission wavelengths were set to 285 nm and 345 nm, respectively. The HPLC system was able to separate melatonin and internal standard (5-fluorotryptamine) from other endogenous indole compounds such as serotonin and tryptophan. Determination down to 0.10 nmol/L was possible, with an intra-assay precision of about 13%. Melatonin was stable in plasma for at least 30 days at about 23 degrees C.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-48687 (URN)12729073 (PubMedID)
    Available from: 2008-10-17 Created: 2008-10-17 Last updated: 2017-12-05
    2. Determination of melatonin in saliva using automated solid-phase extraction, high-performance liquid chromatography and fluorescence detection
    Open this publication in new window or tab >>Determination of melatonin in saliva using automated solid-phase extraction, high-performance liquid chromatography and fluorescence detection
    2006 (English)In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 66, no 3, p. 181-190Article in journal (Refereed) Published
    Abstract [en]

    A sensitive bioanalytical method for the determination of melatonin in saliva by solid‐phase extraction (SPE), high‐performance liquid chromatography (HPLC) and fluorescence detection has been developed and validated. Saliva was collected with a Salivette® sampling device (Sarstedt) and a mixed‐mode SPE column was used for the extraction of melatonin and internal standard (N‐acetyl‐6‐methoxytryptamine) from the saliva. Chromatographic separation was performed using a HyPurity C18 LC column (150×2.1mm) with mobile phase acetonitrile – ammonium hydrogen carbonate buffer, 0.015M, pH6.8 (23:77, v/v). Excitation and emission wavelengths were set to 285nm and 345nm, respectively. The within‐day precision for the method at 50pmol/L was 7.9 % and the between‐day precision was 10.5 %. The limit of quantification was 50pmol/L.

    Keywords
    Circadian rhythm, HPLC, indoleamine, N-acetyl-5-methoxytryptamine, Salivette, SPE
    National Category
    Other Basic Medicine Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-131515 (URN)10.1080/00365510600548777 (DOI)
    Available from: 2010-10-04 Created: 2010-10-04 Last updated: 2018-01-12Bibliographically approved
    3. Determination of eflornithine enantiomers in plasma by precolumn derivatization with o-phthalaldehyde-N-acetyl-l-cysteine and liquid chromatography with UV detection
    Open this publication in new window or tab >>Determination of eflornithine enantiomers in plasma by precolumn derivatization with o-phthalaldehyde-N-acetyl-l-cysteine and liquid chromatography with UV detection
    2010 (English)In: BMC Biomedical chromotography, ISSN 0269-3879, E-ISSN 1099-0801, Vol. 24, no 7, p. 768-773Article in journal (Refereed) Published
    Abstract [en]

    A bioanalytical method for indirect determination of eflornithine enantiomers in 75 mu L human plasma has been developed and validated. L- and D-eflornithine were derivatized with o-phthalaldehyde and N-acetyl-L-cysteine to generate diastereomers which were separated on two serially connected Chromolith Performance columns (RP-18e 100 x 4.6 mm i.d.) by a isocratic flow followed by a gradient flow for elution of endogenous compounds. The diastereomers were detected with UV (340 nm). The between-day precisions for L- and D-eflornithine in plasma were 8.4 and 2.3% at 3 mu m, 4.0 and 5.1% at 400 mu m, and 2.0 and 3.7% at 1000 mu m. The lower limit of quantification was determined to be 1.5 mu m, at which precision was 14.9 and 9.9% for 1- and D-eflornithine, respectively.

    Keywords
    eflornithine, chiral separation, Human African sleeping sickness, cancer
    National Category
    Other Basic Medicine Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-131517 (URN)10.1002/bmc.1361 (DOI)000279367900013 ()
    Available from: 2010-10-04 Created: 2010-10-04 Last updated: 2018-01-12Bibliographically approved
    4. Determination of lamivudine, zidovudine and nevirapine, in capillary blood sampled on filter paper, by liquid chromatography
    Open this publication in new window or tab >>Determination of lamivudine, zidovudine and nevirapine, in capillary blood sampled on filter paper, by liquid chromatography
    2009 (English)In: Journal of Chromatographic Science, ISSN 0021-9665, E-ISSN 1945-239X, Vol. 47, no 10, p. 855-862Article in journal (Refereed) Published
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-96868 (URN)000271527500002 ()
    Available from: 2008-03-19 Created: 2008-03-19 Last updated: 2017-12-14Bibliographically approved
    5. Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper
    Open this publication in new window or tab >>Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper
    Show others...
    2007 (English)In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 45, no 2, p. 282-287Article in journal (Refereed) Published
    Abstract [en]

    A bioanalytical method for the determination of lumefantrine in 100 μl blood applied onto sampling paper, by solid-phase extraction and liquid chromatography, has been developed and validated. Whatman 31 ET Chr sampling paper was pre-treated with 0.75 M tartaric acid before sampling capillary blood to enable a high recovery of lumefantrine. Lumefantrine was extracted from the sampling paper, then further purified using solid-phase extraction and finally quantified with HPLC. The between-day variation was below 10% over the range 0.4-25 μM. The lower limit of quantification was 0.25 μM in 100 μl capillary blood. No decrease in lumefantrine concentration in dried blood spot is seen after 4 months storage at 22 °C. The method was also evaluated in field samples from patients in Tanzania after treatment with lumefantrine/artemether. Lumefantrine could be estimated accurately enough to assess bioavailability and treatment compliance on day 7 (i.e. 4 days after the last dose) after a standard regimen with the lumefantrine/artemether combination.

    Keywords
    Lumefantrine, Sampling paper, Dried blood spots, Capillary blood, Antimalarial drugs, Solid-phase extraction, Liquid chromatography
    National Category
    Pharmaceutical Sciences
    Identifiers
    urn:nbn:se:uu:diva-11919 (URN)10.1016/j.jpba.2007.07.015 (DOI)000250888700014 ()17719735 (PubMedID)
    Available from: 2007-11-06 Created: 2007-11-06 Last updated: 2018-01-12Bibliographically approved
    6. Determination of Tafenoquine in plasma and dried blood spots using liquid chromatography and fluorescence detection
    Open this publication in new window or tab >>Determination of Tafenoquine in plasma and dried blood spots using liquid chromatography and fluorescence detection
    (English)Manuscript (preprint) (Other academic)
    Keywords
    Tafenoquine, sampling paper, dried blood spots, capillary blood, antimalarial drugs, solid-phase extraction, liquid chromatography
    National Category
    Other Basic Medicine Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-131518 (URN)
    Available from: 2010-10-04 Created: 2010-10-04 Last updated: 2018-01-12
  • 172.
    Römsing, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Development of Analytical Methods for Determination of Melatonin in Biological Fluids2005Licentiate thesis, monograph (Other scientific)
  • 173.
    Röttger, Svenja
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Sjöberg, Per J. R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Larhed, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Microwave-Enhanced Copper-Catalyzed N-Arylation of Free and Protected Amino Acids in Water2007In: Journal of combinatorial chemistry, ISSN 1520-4766, E-ISSN 1520-4774, Vol. 9, no 2, p. 204-209Article in journal (Refereed)
    Abstract [en]

    A microwave-enhanced copper-catalyzed protocol for N-arylation using water as the solvent is reported. This fast transformation allows the reaction between various amino acids or amino acid esters and a diverse set of substituted aryl bromides in less than 40 min, affording good yields of non-protected N-arylated amino acids with only minor racemization (6% or less). In addition, online ESI-MS and MS/MS analysis were used to "fish-out" an anionic Cu-containing amino acid complex directly from an ongoing N-arylation reaction.

  • 174.
    Samgina, T. Yu.
    et al.
    Organic Chemistry Department, Moscow State University.
    Gorshkov, V. A.
    Organic Chemistry Department, Moscow State University.
    Artemenko, Konstantin A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Kovalev, S. V.
    N. N. Blokhin Russian Cancer Research Center, Russian Academy of Medicial Sciences.
    Ogourtsov, S. V.
    Biological Department, Moscow State University.
    Zubarev, Roman A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Lebedev, A. T.
    Organic Chemistry Department, Moscow State University.
    Novel natural peptides from Hyla arborea schelkownikowi skin secretion2010In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 24, no 12, p. 1749-1754Article in journal (Refereed)
    Abstract [en]

    Hyla arborea schelkownikowi is one of the leaf frog species inhabiting the southern territories of Russia and the former USSR. This frog species is a member of the Hylidae Rafinesque, 1815 batrachians family. The present study deals with the previously uninvestigated peptidome of the Hyla arborea schelkownikowi skin secretion. Nano-electrospray ionization Fourier transform mass spectrometry (nanoESI-FTMS) of the skin secretion, in the intact form and after acetylation, was selected as the general method of analysis. Electron-capture dissociation (ECD) and collision-induced dissociation (CID) fragmentation were both employed, while de novo sequencing was performed by manual interpretation of the MS data. The suppression of the cyclization of b-ions in the mass spectrometer by the acetylation reaction proved to be very efficient for the de novo sequencing of short peptides. Ten skin peptides were found and all of them, except for bradykinin, had not previously been reported. Six of the peptides belong to the tryptophyllins and related peptides, while three peptides are similar to the aureins.

  • 175. Samgina, T. Yu.
    et al.
    Gorshkov, V. A.
    Vorontsov, Ye. A.
    Artemenko, Konstantin A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Ogourtsov, S. V.
    Zubarev, R. A.
    Lebedev, A. T.
    Mass spectral study of the skin peptide of brown frog Rana temporaria from Zvenigorod population2011In: Journal of Analytical Chemistry, ISSN 1061-9348, E-ISSN 1608-3199, Vol. 66, no 14, p. 1353-1360Article in journal (Refereed)
    Abstract [en]

    Skin secretions of amphibian are an interesting source of biologically active peptides. The present study provides the profile of the skin secretions of the brown frog Rana temporaria from Zvenigorod population (Russia). Sequencing of the skin secretion components has been carried out on an ion cyclotron resonance instrument with electrospray ionization and two methods of fragmentation activation, collisional activation and electron capture. For sequencing of the peptides containing intermolecular C-terminal disulfide cycle two methods of disulfide bond opening have been used: reduction with subsequent alkylation of the free thiol groups and oxidation with performic acid with the formation of sulfo-acid groups. The peptide profile of Rana temporaria studied by a complex mass spectral method has been compared with the data for the frogs of other European populations of this species. For the first time we have revealed ornithokinin-antagonist of the ornithokinin receptor-in skin secretions of amphibians.

  • 176. Samgina, T. Yu.
    et al.
    Gorshkov, V. A.
    Vorontsov, Ye. A.
    Artemenko, Konstantin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Zubarev, R. A.
    Lebedev, A. T.
    Mass spectrometric study of bradykinin-related peptides (BRPs) from the skin secretion of Russian ranid frogs2011In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 25, no 7, p. 933-940Article in journal (Refereed)
    Abstract [en]

    Amphibian skin secretion is known to contain biologically active peptides. Bradykinins and related peptides (BRPs) can be found in these animals, while frogs from the genus Rana are considered to be leaders in the levels and variety of these peptides. A reasonable rationalization of this fact is that bradykinins are efficient defense compounds against predators. Forty-four various BRPs have been identified in the skin secretions of five ranid frog species (R. ridibunda, R. lessonae, R. esculenta, R. temporaria, R. arvalis) from the Zvenigorod region (Moscow district, Russia). Some of these peptides are already known, but the novel ones constitute a significant portion. An interesting group of novel peptides was isolated from R. lessonae. These are bradykinin analogues bearing a tyrosine residue in the 5th or 8th position. [Arg(0), Trp(5), Leu(8)] bradykinin and [Thr(6), Leu(8)] bradykinin that had been isolated from fish and avian species, respectively, were also detected in the frog secretion, supporting the predator defense hypothesis. Furthermore, a novel group of BRPs named 'lessonakinins' was discovered in R. lessonae and R. esculenta. All of them include the [Arg(0), Trp(5), Leu(8)] bradykinin sequence and have some structural resemblance to the precursor of this peptide cloned by Chen and coworkers recently. However, the C-terminal part of the lessonakinins does not match the sequence predicted by Chen, demonstrating possible incompleteness of information obtained by cDNA cloning.

  • 177.
    Samuelsson, Jörgen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
    Arnell, Robert
    Diesen, Jarle
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Tibbelin, Julius
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Paptchikhine, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
    Sjöberg, Per J. R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Development of the Tracer-Pulse method for adsorption studies of analyte mixures in liquid chromatography utilizing mass spectrometric detection2008In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 80, no 6, p. 2105-2112Article in journal (Refereed)
    Abstract [en]

    The tracer-pulse method provides the real adsorption data points directly from simple, straightforward calculations and is therefore a superior method for multicomponent adsorption isotherm determination in HPLC. Only one important problem has restricted its use so far: the tracer peaks are invisible using any conventional detection principle. We present a solution to this problem with an approach with a firm base in analytical chemistry, utilizing stable isotopes and mass spectrometric detection. The new approach was used for the determination of binary adsorption isotherms, and a systematic investigation was made of its main sources of error. With this modification, the tracer method can be a prime choice for future characterizations of multicomponent separation systems and of competitive drug binding studies.

  • 178.
    Samuelsson, Jörgen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Edström, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Forssén, Patrik
    Analytical Chemistry, Department of Chemistry and Biomedical Sciences, Karlstad University, Sweden.
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Injection profiles in liquid chromatography: I. A fundamental investigation2010In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1217, p. 4306-4312Article in journal (Refereed)
    Abstract [en]

    This is a fundamental experimental and theoretical investigation on how the injection profile depends on important experimental parameters. The experiments revealed that the injection profile becomes more eroded with increased (i) flow rate, (ii) viscosity of the eluent, (iii) size of the solute, (iv) injection volume and (v) inner diameter of the injection loop capillary. These observations cannot be explained by a 1D-convection-diffusion equation, since it does not account for the effect of the parabolic flow and the radial diffusion on the elution profile. Therefore, the 1D model was expanded into a 2D-convection-diffusion equation with cylindrical coordinates, a model that showed a good agreement with the experimental injection profiles dependence on the experimental parameters. For a deeper understanding of the appearance of the injection profile the 2D model is excellent, but to account for injection profiles of various injection volumes and flow rates in preparative and process-chromatography using computer-optimizations, a more pragmatic approach must be developed. The result will give guidelines about how to reduce the extra-column variance caused by the injection profile. This is important both for preparative and analytical chromatography; in particular for modern analytical systems using short and narrow columns.

  • 179.
    Samuelsson, Jörgen
    et al.
    Department of Chemistry and Biomedical Sciences, Karlstad University, Sweden.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Expanding the elution by characteristic point method for determination of various types of adsorption isotherms2011In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 24, p. 3737-3742Article in journal (Refereed)
    Abstract [en]

    Important improvements have recently been made on the elution by characteristic point (ECP) method to increase the accuracy of the determined adsorption isotherms. However, the method has so far been limited/used for only type I adsorption isotherms (e.g. Langmuir, Toth, bi-Langmuir). In this study, general strategies are developed to expand the ECP method for the determination of more complex adsorption isotherms including such containing inflection points. We will exemplify the methodology with type II, type III and type V isotherms. Guidelines are given for how to determine such isotherms using the ECP method and for the experimental considerations that must be taken into account or that may be eliminated in the particular case.

  • 180.
    Samuelsson, Jörgen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Undin, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Törncrona, Anders
    Eka Chemicals AB, Separation Products,Sweden.
    Fornstedt, Torgny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Improvement in the generation of adsorption isotherm data in the elution by characteristic points method: the ECP-slope approach2010In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1217, no 46, p. 7215-7221Article in journal (Refereed)
    Abstract [en]

    The elution by characteristic points (ECP) method is a very rapid and precise method for determination of the phase system equilibrium of phase systems in broad solute concentration ranges. Thus, the method is especially suitable for rapid characterization of high efficient separation systems. One important source of error, the effects by the post-loop dispersion, was eliminated in a recent investigation. In this study, the systematic error caused by the selection of the integration starting point at concentration equal to 0 is eliminated. This is done by developing and validating a new procedure for isotherm data generation; the ECP-slope method. The method generates raw slope data of the adsorption isotherm instead of raw adsorption data by integrations as the classical ECP does. Both numerical and experimental data were used for the comparison of the classical ECP approach with the slope-ECP method.

  • 181.
    Santos-Neto, Alvaro J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Lancas, Fernando M.
    Sjöberg, Per J.R.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Simultaneous analysis of five antidepressant drugs using direct injection of biofluids in a capillary restricted-access media-liquid chromatography-tandem mass spectrometry system2008In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1189, no 1-2, p. 514-522Article in journal (Refereed)
    Abstract [en]

    Direct analysis, with minimal sample pretreatment, of antidepressant drugs, fluoxetine, imipramine, desipramine, amitriptyline, and nortriptyline in biofluids was developed with a total run time of 8 min. The setup consists of two HPLC pumps, injection valve, capillary RAM-ADS-C18 pre-column and a capillary analytical C 18 column connected by means of a six-port valve in backflush mode. Detection was performed with ESI-MS/MS and only 1 mu m of sample was injected. Validation was adequat