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  • 1.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Guijarro, David
    Tanner, David
    Preparation and Use of Aziridino Alcohols as Promoters for the Enantioselective Addition of Dialkylzinc Reagents to N-(Diphenylphosphinoyl) Imines1997In: J. Org. Chem., no 62, p. 7364-7375Article in journal (Refereed)
  • 2. Baudin, Micael
    et al.
    Wojcik, Mark
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    A molecular dynamics study of MgO(111) slabs1997In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 375, no 2-3, p. 374-384Article in journal (Refereed)
    Abstract [en]

    Constant stress - constant temperature molecular dynamics simulations are reported for 30 Angstrom thick crystalline MgO (111) slabs with 2-D periodicity in the temperature range 10-1100 K. The 10 K run was 3.75 ps, the 300 K run was 41.25 ps while the others were 11.25 ps. The shell-model potential was used and the long-range interaction was taken into account with the 2-D Ewald summation technique. Two different models have been used in order to achieve the necessary charge compensation for the polar (111) surface. The relaxation of the surface structure and its temperature dependence have been investigated and compared with bulk MgO. The average coordination number in the surface layer and the surface energy are presented. The dynamics in the slab system is presented in terms of atomic mean-square displacements and vibrational density-of-states curves as a function of depth from the surface. (C) 1997 Elsevier Science B.V.

  • 3. Bedekar, Ashutosh V.
    et al.
    Koroleva, Elise B.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Investigation of the Effects of the Structure and Chelate Size of Bis-oxazoline Ligands in the Asymmetric Copper-Catalyzed Cyclopropanation of Olefins: Design of a New Class of Ligands1997In: J. Org. Chem., no 62, p. 2518-2526Article in journal (Refereed)
  • 4. Bischof, Gerhard
    et al.
    Silbernagl, Alexander
    Hermansson, Kersti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Probst, Michael
    Quantum chemical study of the molecular dynamics of hydrated Li+ and Be2+ cations1997In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 65, no 5, p. 803-816Article in journal (Refereed)
    Abstract [en]

    Molecular dynamics simulations of clusters of Li+ and Be2(+) cations with up to 12 water molecules were performed calculating the particle trajectories using Hartree-Fock-derived forces. It was found that independent of the starting configuration tetrahedral clusters are obtained in less than 1 ps. Only for Li+ clusters, transition states with five and three water molecules are found. We discuss the structures of the clusters and the vibrational dynamics of the water molecules and compare them with other ab initio simulations, with simulations using analytical potential functions, and with static calculations. Water-dissociation (hydrogen transfer) reactions which take place at elevated temperatures were investigated. (C) 1997 John Wiley & Sons, Inc.

  • 5.
    Eriksson, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Nyholm, L
    Electrochemical detection of disodium 3,3 '-azobis-(6-hydroxy-)benzoate (olsalazine sodium)1997In: ELECTROANALYSIS, ISSN 1040-0397, Vol. 9, no 16, p. 1291-1293Article in journal (Refereed)
    Abstract [en]

    Electrochemical detection of disodium 3,3'-azobis-(6-hydroxy-)benzoate, olsalazine sodium, in reversed phase Liquid chromatography is shown to provide a detection limit of 40 fmol and a linear range extending up to 4 nmol for an injection volume of 20 mu

  • 6.
    Fast, K J
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Bergström, M
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Hedberg, E
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Cheng, A
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Lu, L
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Wu, F
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Bergström, E
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET.
    Tolmachev, Vladimir
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Section of Nuclear Medicine and PET. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    76-Br-bromodeoxyuridine marker with PET-preclinical validation studies1997In: Journal of labelled compounds & radiopharmaceuticals, ISSN 0362-4803, E-ISSN 1099-1344, Vol. 40, no 5, p. 391-393Article in journal (Refereed)
  • 7.
    Feldman, H
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences.
    Hartvig, P
    Wiklund, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Doucette, A-M
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Gee, A
    Uhlin, J
    Langstrom, B
    Regional distribution of 11C-labeled lidocaine, bupivacaine, and ropivacaine in the heart, lungs, and skeletal muscle of pigs studied with positron emission tomography.1997In: Biopharm. Drug Dispos., Vol. 18, p. 151-Article in journal (Refereed)
  • 8.
    Fridstrom, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Nyholm, L
    Netscher, T
    Walther, W
    Lundell, N
    Markides, KE
    Neutral cyclodextrins as chiral agents for enantiomeric separations of chromanes in capillary electrophoresis1997In: CHROMATOGRAPHIA, ISSN 0009-5893, Vol. 44, no 5-6, p. 313-319Article in journal (Refereed)
    Abstract [en]

    Six different cyclodextrins with varying cavity size and rim substitution were used as chiral agents for the enantiomeric separation of eight chromane compounds or analogues using capillary electrophoresis. It is shown that the cyclodextrin type and conc

  • 9.
    Gogoll, Adolf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Grennberg, Helena
    Uppsala University.
    Axen, A
    Uppsala University.
    Chemical shift assignment of geminal protons in 3,7-diazabicyclo [3.3.1]nonanes: An unexpected deviation from the axial/equatorial chemical shift order1997In: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 35, no 1, p. 13-20p. 13-20Article in journal (Refereed)
    Abstract [en]

    The chemical shift order of axial and equatorial methylene protons in 1,5-disubstituted 3,7-diazabicyclo [3.3.1]nonan-9-ones may be altered by substituents in the 1,5-positions, but the corresponding alcohols behave differently. Unambiguous signal assign

  • 10.
    Gogoll, Adolf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Axen, Andreas
    Uppsala University.
    (π-Allyl)palladium complexes with N,N'-diphenylbispidinone derivatives as a new type of chelating nitrogen ligand: Complexation studies, spectroscopic properties, and an x-ray structure of (3,7-diphenyl-1,5-dimethylbispidinone)[(1,3-η(3)-propenyl)-pal1997In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 16, no 6, p. 1167-1178p. 1167-1178Article in journal (Refereed)
    Abstract [en]

    A series of 3,7-diazabicyclo[3.3.1]nonane (bispidine) derivatives have been synthesized, and their properties as bidentate nitrogen ligands for (pi-allyl)palladium complexes have been investigated. Complexes of these ligands and of N,N'-diphenylpiperazin

  • 11.
    Jacobson, GB
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Markides, KE
    Langstrom, B
    Supercritical fluid synthesis and on-line preparative supercritical fluid chromatography of C-11-labelled compounds in supercritical ammonia1997In: ACTA CHEMICA SCANDINAVICA, ISSN 0904-213X, Vol. 51, no 3, p. 418-425Article in journal (Refereed)
    Abstract [en]

    An automated supercritical fluid synthesis (SFS) system, designed for reaction and on-line preparative supercritical fluid chromatography (SFC) of C-11-labelled (t(1/2) = 20.3 min) compounds in supercritical ammonia, is described. The synthesis and on-li

  • 12.
    Jacobson, GB
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Moulder, R
    Lu, L
    Bergstrom, M
    Markides, KE
    Langstrom, B
    Supercritical fluid extraction of C-11-labeled metabolites in tissue using supercritical ammonia1997In: ANALYTICAL CHEMISTRY, ISSN 0003-2700, Vol. 69, no 3, p. 275-280Article in journal (Refereed)
    Abstract [en]

    Supercritical fluid extraction (SFE) of C-11-labeled tracer compounds and their metabolites from biological tissue was performed using supercritical ammonia in an attempt to develop a rapid extraction procedure that allowed subsequent analysis of the lab

  • 13.
    Juvancz, Z
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Jicsinszky, L
    Markides, KE
    Phosphated cyclodextrins as new acidic chiral additives for capillary electrophoresis1997In: JOURNAL OF MICROCOLUMN SEPARATIONS, ISSN 1040-7685, Vol. 9, no 8, p. 581-589Article in journal (Refereed)
    Abstract [en]

    The study describes the use of alpha,beta, and gamma phosphated cyclodextrins (CDs) for chiral separation by capillary electrophoresis (CE). A systematic study was performed to establish the effect of such variables as the type and concentration of chira

  • 14.
    Juvancz, Z
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Markides, KE
    Jicsinszky, L
    Enantiomer separation of disopyramide with capillary electrophoresis using various cyclodextrins1997In: ELECTROPHORESIS, ISSN 0173-0835, Vol. 18, no 6, p. 1002-1006Article in journal (Refereed)
    Abstract [en]

    Enantiomers of disopyramide display different biological actions, and therefore chiral selective analysis is necessary. Fifteen different cyclodextrins (CDs) and CD derivatives were tested as capillary electrophoresis (CE) additives for the chiral separa

  • 15.
    Koivisto, P
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Danielsson, R
    Markides, KE
    Factors affecting the preparation of packed capillary columns in supercritical carbon dioxide media1997In: JOURNAL OF MICROCOLUMN SEPARATIONS, ISSN 1040-7685, Vol. 9, no 2, p. 97-103Article in journal (Refereed)
    Abstract [en]

    In this study, packed capillary columns were prepared using supercritical carbon dioxide as a packing carrier. A factorial design was used to examine the effect that four selected factors have on the packing performance. The investigated factors were: 1)

  • 16.
    Meng, QS
    et al.
    Uppsala University.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Thibblin, Alf
    Uppsala University.
    Concerted and stepwise solvolytic elimination and substitution reactions: Stereochemistry and substituent effects1997In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 119, no 6, p. 1217-1223p. 1217-1223Article in journal (Refereed)
    Abstract [en]

    Solvolysis of the R,R and R,S isomers 2a-X and 2b-X, respectively, (X = I, Br, OBs) in 25 vol % acetonitrile in water gives the elimination products 4, 5a, and 5b along with the substitution products 2a-OH, 2b-OH, 2a-NHCOMe, and 2b-NHCOMe. The rates of e

  • 17.
    Petersson, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    On-Line Solid Phase Adsorption / Supercritical Fluid Extraction / Supercritical Fluid Chromatography1997Licentiate thesis, monograph (Other academic)
  • 18.
    Pihlström, Tuija
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Analytical Chemistry.
    Hellström, Anna
    Axelsson, Victoria
    Gas chromatographic analysis of pesticides in water with off-line solid phase extraction1997In: Analytica Chimica Acta, Vol. 356, p. 155-163Article in journal (Refereed)
  • 19. Rönn, Magnus
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Bäckvall, Jan-E
    Application of O2-DMSO as Reoxidant in the Pd(II)-Catalyzed 1,4-Oxidation of 5-Substituted 1,3-Cyclohexadienes1997In: Acta Chemica Scandinavica, no 51, p. 773-777Article in journal (Refereed)
  • 20. Rönn, Magnus
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Bäckvall, Jan-E
    The Use of Stabilized Carbon Nucleophiles in Palladium(II)-Catalyzed 1,4-Oxidation of Conjugated Dienes1997In: Tetrahedron Letters, Vol. 38, no 20, p. 3603-3606Article in journal (Refereed)
  • 21.
    Sjoberg, PJR
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Markides, KE
    New supercritical fluid chromatography interface probe for electrospray and atmospheric pressure chemical ionization mass spectrometry1997In: JOURNAL OF CHROMATOGRAPHY A, ISSN 0021-9673, Vol. 785, no 1-2, p. 101-110Article in journal (Refereed)
    Abstract [en]

    A new supercritical fluid chromatography interface probe has been constructed for atmospheric pressure ionization mass spectrometry (API-MS). The use of API-MS effectively separates the ionization and mass analysis regions. Furthermore, a sheath-liquid f

  • 22.
    Stefansson, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Sudor, J
    Hong, MF
    Chmelikova, J
    Chmelik, J
    Novotny, MV
    Aminodextran as a migration moderator in capillary gel electrophoresis of charged polysaccharides1997In: ANALYTICAL CHEMISTRY, ISSN 0003-2700, Vol. 69, no 18, p. 3846-3850Article in journal (Refereed)
    Abstract [en]

    Aminodextran (AD) is shown here as an effective electrolyte additive for a size-dependent separation of hyaluronate (HA) oligomers in capillary gel electrophoresis. AD interacts mainly with the negatively charged HA through an ion-exchange mechanism, whi

  • 23.
    Stålberg, Olle
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Drug purity determination by capillary electrophoresis: Practical and theoretical aspects on peak shape and resolution1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Capillary electrophoresis was used for separation and determination ofdrugs. Structural analogues, enantiomers and rotamers were separated usingderivatized β-cyclodextrins and γ-cyclodextrins as selectors.In order to improve these separation systems different kinds of chargedamphiphiles were introduced in the background electrolyte (BGE).Addition of charged amphiphiles to the BGE reduces the adsorption ofdrugs with the same charge as the amphiphile and it will also alter theelectroosmotic flow (EOF). Regulation of the EOF was used to improve theresolution as well as for decreasing the time of analysis. A new theory wasdeveloped where the magnitude of the EOF is described as a function of theamphiphile concentration in the BGE. A good correlation between thetheoretical calculated values and the experimental data was obtained.

    Methods for control of the overloading effects in drug puritydeterminations are also presented. Regulation of the peak shape of anoverloaded peak and for minimization of the electromigration dispersion ofthe sample zone were accomplished by addition of tetraalkylammoniumions to the BGE having a mobility similar to the mobility of the sample ions.Presence of selectors such as cyclodextrins enables tuning of the conductivityof the sample zone. This technique was successfully applied for separationenantiomers and in determination of enantiomeric drug purity. Laserinduced fluorescence detection, promote minimization of the overloadingeffects by injection of a lower sample concentration.A He-Cd laser and a frequency doubled argon-ion laser were applied asexcitation sources in drug purity determinations. The high detectability offluorescent compounds using LIF-detection improved the limit ofdetermination of impurities.

  • 24. Södergren, Mikael
    et al.
    Alonso, Diego
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Readily available nitrene precursors increase the scope of Evans' asymmetric aziridination of olefins1997In: Tetrahedron Asymmetry, Vol. 8, no 21, p. 3563-3565Article in journal (Refereed)
  • 25. Södergren, Mikael
    et al.
    Alonso, Diego
    Bedekar, Ashutosh V.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Preparation and Evaluation of Nitrene Precursors (PhI=NSO2Ar) for the Copper-Catalyzed Aziridiantion of Olefins1997In: Tetrahedron Letters, Vol. 38, no 39, p. 6897-6900Article in journal (Refereed)
  • 26. Tanner, David
    et al.
    Tedenborg, Lars
    Almario, Antonio
    Pettersson, Ingrid
    Csöregh, Ingeborg
    Kelly, Nicholas
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Högberg, Thomas
    Total Synthesis of Balanol, Part 2. Completion of the Synthesis and Investigation of the Structure and Reactivity of Two Key Heterocyclic Intermediates1997In: Tetrahedron, Vol. 53, no 13, p. 4857-4868Article in journal (Refereed)
  • 27.
    Tedenborg, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Synthetic studies on the natural products Zoanthamine and Balanol1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Three main projects are described in this thesis. In the first, a stereocontrolled route tothe marine alkaloid Zoanthamine was studied. A convergent approach based on thechiral starting materials (S)-Perillyl alcohol and (R)-4,5-Dihydro-5-hydroxymethyl-2(3H)-furanone was developed. Some of the key reactions for control ofstereochemistry were: Sharpless asymmetric epoxidation, [3,3] sigmatropicrearrangement, iodolactonization-elimination, and diastereoselective alkylation.Intermediates corresponding to the C1-C5, C6-C10, and Cll-C24 fragments ofZoanthamine have been synthesized regio- and stereoselectively.

    In the second project, the total synthesis of (-) Balanol has been accomplished.Enantioselective synthesis of the hexahydroazepine ring involved introduction of thetwo stereogenic centres via Sharpless asymmetric epoxidation of an acyclic allylicalcohol, followed by acid-catalysed ring-opening of a bicyclic aziridine intermediate.

    The third project deals with a further study of the regio- and stereoselective ring-opening reaction discovered in the balanol project. The ring-opening of the three chiralbicyclic systems (one epoxide and two aziridines) was investigated, with a number ofdifferent nucleophiles and counter-ions. In most cases, excellent regio- andstereoselective was observed. The results from DNMR experiments, X-raycrystallography, and molecular mechanics calculations were used to provide anexplanation for the observed selectivity, which is postulated to originate from acombination of steric and electronic factors.

  • 28. Valverde, Antonio
    et al.
    Pihlström, Tuija
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Analytical Chemistry.
    Andersson, Arne
    Analysis of pyraclofos in crops by the Swedish National Food Administration gas chromatographic multiresidue method1997In: Analytica Chimca Acta, Vol. 338, p. 63-68Article in journal (Refereed)
  • 29.
    Wallenborg, SR
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Markides, KE
    Nyholm, L
    A microelectrochemical detector for use at low linear velocities in capillary column systems1997In: ANALYTICA CHIMICA ACTA, ISSN 0003-2670, Vol. 344, no 1-2, p. 77-85Article in journal (Refereed)
    Abstract [en]

    An end-column microelectrochemical detector, based on a 25 mu m platinum electrode, was used in miniaturised flow and separation systems, at linear mobile phase velocities below 0.1 cm s(-1) (i.e. a volumetric flow of a few mu l min(-1) for a 200 mu m i

  • 30.
    Wallenborg, SR
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Markides, KE
    Nyholm, L
    Development of an amperometric detector for packed capillary column supercritical fluid chromatography1997In: ANALYTICAL CHEMISTRY, ISSN 0003-2700, Vol. 69, no 3, p. 439-445Article in journal (Refereed)
    Abstract [en]

    Amperometric detection at a naked platinum microelectrode is shown to be compatible with pressure-programmed packed capillary column supercritical fluid chromatography (SFC) using carbon dioxide modified with as little as 1% acetonitrile, Amperometric de

  • 31.
    Wallenborg, SR
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Markides, KE
    Nyholm, L
    Oxidative and reductive amperometric detection of phenolic and nitroaromatic compounds in packed capillary column supercritical fluid chromatography1997In: JOURNAL OF CHROMATOGRAPHY A, ISSN 0021-9673, Vol. 785, no 1-2, p. 121-128Article in journal (Refereed)
    Abstract [en]

    Oxidative and reductive amperometric detection of phenols, nitroaromatic compounds and a cyclic ketone is demonstrated in packed capillary column supercritical fluid chromatography (SFC). The detection was performed in combination with isobaric, as well

  • 32.
    Wallenborg, Susanne R.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Selectivity and sensitivity in supercritical fluid and liquid chromatography, using capillary columns and microelectrochemical detection1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The obtainable selectivity of capillary column supercritical fluid chromatography wasstudied by the direct and indirect enantiomeric separation of some medium polarcompounds, i.e., benzodiazepines. The possibility to complement this chromatographictechnique with sensitive detection was pursued by the development of a micro-electrochemical detector, which was based on the impinging-jet principle and a 25 μmplatinum electrode. The detector was evaluated in both capillary column supercritical fluidand liquid chromatography (SFC and LC).

    In capillary column SFC, the amperometric detector was shown to be compatible withboth oxidative and reductive detection, as well as, pressure programmed conditions usingcarbon dioxide, modified with small amounts (i.e., less than 8%) of water, acetonitrile ormethanol, as the mobile phase. The compatibility with various modifiers is important asthe use of modified mobile phases in SFC generally results in altered selectivity, shorteranalysis time and the possibility to analyse more polar compounds. Using the presentdetector, a total number of about 20 different compounds, including, e.g., ferrocenes,phenols and nitroaromatic compounds, have been detected in carbon dioxide basedmobile phases with medium to low picogram detection limits. The detector response wasfound to be linear for injections of between ~0.1 and 4 ng of the analytes for bothoxidative and reductive amperometric detection. The microelectrode assembly could beemployed for at least six days of continuous operation in the SFC system. The relativestandard deviation in the peak height for ng injections of analyte was found to be ca. 5%under both pressure programmed and isobaric conditions. The stability, detection limitand reproducibility of the response of the present detector are notably better than thosepreviously reported.

    The study of the detector in LC was focused on the detection problems associated witha miniaturisation of the separation system. It was found that the detector could be placedup to one column inner diameter (i.e., 200 μm) from the column outlet with preservedsensitivity and efficiency. No significant dependence of the peak current on the positionof the electrode in the y- and z-directions versus the column outlet was observed.Moreover, the detector current was found to be insensitive to variations of the mobilephase linear velocity and concentration of supporting electrolyte. These features shouldfacilitate a rapid and reproducible positioning of the electrode versus the column outletand, additionally, render detection in normal-phase LC possible.

  • 33.
    Ögren, Mattias
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Synthesis of 11C-labelled monosaccharides1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The synthesis of some 11C-labelled (tl/2=20.3 min) monosaccharides is presented. Terminal labelled alkenes were synthesized and selectively oxidized using asymmetric dihydroxylation (AD) and palladium(II)-promoted oxidation. The labelled polyols obtained after the AD were submitted to enzymatic oxidations. The use of polymer-bound triphenylphosphine in the synthesis of three 11C-labelled aromatic alkenes was also investigated.

    The 11C-labelled alkenes were synthesized from [11C]methyltriphenyl phosphineiodide. Unreacted triphenylphosphine was quenched prior to the AD. In the synthesis of D-[6-11C]glucose and D-[1-11C]mannitol, the protecting groups were removed by acid hydrolysis and purified on high performance liquid chromatography (HPLC). The decay corrected radiochemical yields were 25 % in the synthesis of D-[6-11C]glucose, and 29 % in the synthesis of D-[1-11C]mannitol.

    In the synthesis of 2-deoxy-D-[1-11C]glucose, the 11C-labelled alkene was oxidized with palladium(II) chloride and water. The resulting labelled aldehyde was deprotected and the product was purified on HPLC. The decay corrected radiochemical yield was 28 %.

    D-[1-11C]Mannitol and D-[ 1-11C]glucitol were synthesized using a Wittig reactionand an AD. Enzymatic oxidation of the two labelled polyols yielded D-[1-11C]fructose and D-[1-11C]glucose, repectively. D-Mannitol dehydrogenase was used for converting D-[1-11C]mannitol to D-[1-11C]fructose and xylitol oxidase for converting D-[1-11C]glucitol to D-[1-11C]glucose. The decay corrected radiochemical yield was 13 % in the synthesis of D-[1-11C]fructose. In the synthesis of D-[1-11C]glucitol the radiochemical yield was low in the AD affording D-[l-11C]glucose in low yield.

    In the polymer-bound synthesis of 11C-labelled aromatic alkenes three aldehydes,benzaldehyde, para-nitrobenzaldehyde and para-methoxybenzaldehyde, were used to synthesize the corresponding alkenes. The decay corrected radiochemical yields were 29-65%.

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