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Noninvasive Assessment of the Role of Cyclooxygenases in Cardiovascular Health: A Detailed HPLC/MS/MS Method. Methods Enzymol 2007; 433:51-72. [DOI: 10.1016/s0076-6879(07)33003-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Anari MR, Burton RW, Gopaul S, Abbott FS. Metabolic profiling of valproic acid by cDNA-expressed human cytochrome P450 enzymes using negative-ion chemical ionization gas chromatography-mass spectrometry. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2000; 742:217-27. [PMID: 10901126 DOI: 10.1016/s0378-4347(00)00161-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A sensitive negative ion chemical ionization (NCI) gas chromatographic-mass spectrometric (GC-MS) method was modified for the quantitation of valproic acid (VPA) metabolites generated from in vitro cDNA-expressed human microsomal cytochrome P450 incubations. The use of the inherent soft ionization nature of electron-capture NCI to achieve high sensitivity enabled us to conduct kinetic studies using small amounts of recombinant human P450 enzymes. The assay is based on the selective ion monitoring of the intense [M-181] fragments of pentafluorobenzyl (PFB) esters in the NCI mode, and has the following features: (1) a micro-extraction procedure to isolate VPA metabolites from small incubation volumes (100 microl); (2) a second step derivatization with tert.-butyldimethylsilylating reagents to enhance sensitivity for hydroxylated metabolites; (3) a short run-time (<30 min) while maintaining full separation of 15 VPA metabolites by using a narrow-bore non-polar DB-1 column plus a new temperature gradient; and (4) good reproducibility and accuracy (intra- and inter-assay RSDs <15%, bias <15%) by using seven deuterated derivatives of analytes as internal standards. The derivatives of mono-and diunsaturated metabolites, like the parent drug, produced abundant [M-181](-) ions while the hydroxylated metabolites gave an ion at m/z of 273, corresponding to the [M-181](-) ion of the tert.-butyldimethylsilyl ethers. In conclusion, the GC-NCI-MS analysis of valproate metabolites provided us with a high resolution and sensitivity necessary to conduct metabolic and kinetic studies of valproic acid in small volume samples typical of the in vitro cDNA-expressed micro-incubation enzymatic systems.
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Affiliation(s)
- M R Anari
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
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Gopaul SV, Farrell K, Abbott FS. Gas chromatography/negative ion chemical ionization mass spectrometry and liquid chromatography/electrospray ionization tandem mass spectrometry quantitative profiling of N-acetylcysteine conjugates of valproic acid in urine: application in drug metabolism studies in humans. JOURNAL OF MASS SPECTROMETRY : JMS 2000; 35:698-704. [PMID: 10862121 DOI: 10.1002/1096-9888(200006)35:6<698::aid-jms996>3.0.co;2-s] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report a GC/NICI-MS assay and a LC/ESI-MS/MS assay for the analysis of N-acetylcysteine (NAC) conjugates of (E)-2,4-diene VPA (NAC I and NAC II) identified in humans. The assay also includes the analysis of the NAC conjugate of 4,5-epoxy VPA (NAC III), an identified metabolite in rats treated with 4-ene VPA for its use in metabolic studies in animals. The highly sensitive GC/MS assay was designed to monitor selectively the diagnostic and most abundant [M - 181](-) fragment anion of the di-PFB derivatives of NAC I, NAC II, and NAC IV, the internal standard (IS) and the PFB derivative of NAC III. The higher selectivity of LC/MS/MS methodology was the basis for an assay which could identify and quantitate the underivatized conjugates simultaneously using MRM of the diagnostic ions m/z 130 and 123 arising from the CID of their protonated molecular ions [MH](+). The GC/MS assay employed liquid-liquid extraction whereas the LC/MS/MS assay used a solid-phase extraction procedure. Linearity ranges of the calibration curves were 0.10-5.0microg ml(-1) by GC/MS and 0.10-1.0microg ml(-1) by LC/MS/MS for NAC I, NAC II and NAC III (r(2) = 0.999 or better). Both assays were validated for NAC I and NAC II and provided good inter- and intra-assay precision and accuracy for NAC I and NAC II. The LOQ by LC/MS/MS was 0.1microg ml(-1), representing 1 ng of NAC I and NAC II. The same LOQ (0.1microg ml(-1)) was observed by GC/MS and was equivalent to 100 pg of each metabolite. NAC III was detected at concentrations as low as 0.01 microg ml(-1) by both methods. The total urinary excretion of the NAC conjugates in four patients on VPA therapy was determined to be 0.004-0.088% of a VPA dose by GC/MS and 0.004-0. 109% of a VPA dose by LC/MS/MS.
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Affiliation(s)
- S V Gopaul
- Faculty of Pharmaceutical Sciences, 214 East Mall, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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Wheelan P, Zirrolli JA, Murphy RC. Low-energy fast atom bombardment tandem mass spectrometry of monohydroxy substituted unsaturated fatty acids. BIOLOGICAL MASS SPECTROMETRY 1993; 22:465-73. [PMID: 8357860 DOI: 10.1002/bms.1200220808] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The low-energy collision-induced dissociation (CID) of the carboxylate anions generated by fast atom bombardment ionization of monohydroxy unsaturated fatty acids derived from oleic, linoleic, linolenic and arachidonic acids were studied in a tandem quadrupole mass spectrometer. The collisional activation spectra revealed structurally informative ions as to the position of the hydroxyl substituent in relationship to the sites of unsaturation. Five mechanisms are proposed for the fragmentation of hydroxyl substituted unsaturated fatty acids and are dependent upon the presence of alpha- or beta-unsaturation sites. These mechanisms include charge-remote allylic fragmentation, charge-remote vinylic fragmentation, charge-driven allylic fragmentation, charge-driven vinylic fragmentation, and homolytic fragmentation by an oxy-Cope rearrangement process. The assignment of specific fragmentation pathways was supported in many instances with deuterium-labeled analogs. Although no single fragmentation mechanism appears to predominate, a rational approach to the interpretation of these CID spectra is proposed. The CID spectra of unknown compounds could be used to establish the hydroxyl substituent position in relationship to certain sites of unsaturation but would not be indicative of all double bond locations. The oxy-Cope rearrangement is specific for a structural unit, namely the 3-hydroxy-1,5-diene moiety.
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Affiliation(s)
- P Wheelan
- National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206
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Tamvakopoulos CS, Anderson VE. Detection of acyl-coenzyme A thioester intermediates of fatty acid beta-oxidation as the N-acylglycines by negative-ion chemical ionization gas chromatography-mass spectrometry. Anal Biochem 1992; 200:381-7. [PMID: 1632504 DOI: 10.1016/0003-2697(92)90483-n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
An analytical method for the separation and quantitation of acyl-CoA thioesters by gas chromatography-mass spectrometry is described. The method utilizes glycine aminolysis of the acyl-CoA thiolesters, esterification with pentafluorobenzyl bromide followed by gas chromatographic separation, and detection by negative chemical ionization mass spectrometry of the N-acylpentafluorobenzyl glycinates. The glycine aminolysis provides over 100-fold discrimination against oxygen esters and obviates the difficulty of removing trace contaminants of free fatty acids. The limit of detection of the described methodology for palmitoyl-CoA has been found to be 300 fmol, which improves at shorter chain lengths. Baseline separation was obtained for a standard mixture of seven acyl-CoAs (60 pmol injected) containing butyryl-CoA, hexanoyl-CoA, octanoyl-CoA, decanoyl-CoA, lauroyl-CoA, myristoyl-CoA, and palmitoyl-CoA. The above procedure is also applicable to the alpha-beta unsaturated and 3-hydroxyacyl-CoA derivatives, making it possible to quantify all of the intermediates in fatty acid oxidation, except the 3-ketoacyl-CoAs, in a single procedure.
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Affiliation(s)
- C S Tamvakopoulos
- Department of Chemistry, Brown University, Providence, Rhode Island 02912
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Garland W, Huselton C, Kolinsky F, Liberato D. A road less travelled: Normal phase microbore liquid chromatography—mass spectrometry using direct liquid introduction. Trends Analyt Chem 1991. [DOI: 10.1016/0165-9936(91)85018-m] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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8
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Caesar JP, Sheeley DM, Reinhold VN. Femtomole oligosaccharide detection using a reducing-end derivative and chemical ionization mass spectrometry. Anal Biochem 1990; 191:247-52. [PMID: 2085170 DOI: 10.1016/0003-2697(90)90215-u] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A bimodal reagent (pentafluorobenzyl aminobenzoate) has been synthesized to improve oligosaccharide isolation, detection, and structural characterization. The reagent is glycosidically attached to the reducing end of glycan residues, imparts fluorescent and uv properties for chromatographic detection, and functions as an efficient electron trap under negative ion chemical ionization mass spectrometry for femtomole detectability. Facile ester cleavage and pentafluorobenzyl elimination provides a single molecular-weight-related fragment in high abundance. Procedures are described for reagent synthesis, purification, and oligosaccharide conjugation. Carbohydrate samples derivatized with this reagent are evaluated by high-performance liquid chromatography and supercritical fluid chromatography (SFC) and for sensitivity by SFC negative ion chemical ionization mass spectrometry.
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Affiliation(s)
- J P Caesar
- Harvard University School of Public Health, Boston, Massachusetts 02115
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9
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Blair IA. Electron-capture negative-ion chemical ionization mass spectrometry of lipid mediators. Methods Enzymol 1990; 187:13-23. [PMID: 2233337 DOI: 10.1016/0076-6879(90)87004-m] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Hammonds TD, Blair IA, Falck JR, Capdevila JH. Resolution of epoxyeicosatrienoate enantiomers by chiral phase chromatography. Anal Biochem 1989; 182:300-3. [PMID: 2610347 DOI: 10.1016/0003-2697(89)90598-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A chromatographic method is described for the direct enantiomeric characterization of all four regioisomeric epoxyeicosatrienoic acid (EET) metabolites generated by the cytochrome P450 arachidonate epoxygenase pathway. Following esterification, the individual methyl or pentafluorobenzyl esters are resolved by chiral phase HPLC utilizing a Chiralcel OB or OD column. This methodology will find analytical and preparative applications for chiral epoxides since it is convenient and efficient and does not destroy the epoxide functionality.
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Affiliation(s)
- T D Hammonds
- Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232
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Kassahun K, Burton R, Abbott FS. Negative ion chemical ionization gas chromatography/mass spectrometry of valproic acid metabolites. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1989; 18:918-26. [PMID: 2508808 DOI: 10.1002/bms.1200181012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A negative ion chemical ionization (NICI) gas chromatographic/mass spectrometric method is described for the identification of 15 valproic acid (VPA) metabolites as their pentafluorobenzyl derivatives. Samples analyzed were serum, urine and saliva taken from a volunteer on VPA at steady state and also given selected doses of (2H6)VPA. Metabolite peaks were identified by comparison to synthetic standards. All the metabolites, like the parent drug, produced abundant [M - 181]- ions, except 3-keto VPA, which gave an [M - 181 - CO2]- ion. Using the NICI method, two new VPA metabolites were identified. One of these metabolites was characterized as 4'-keto-2-ene VPA by synthesis, while the second one appeared to be a positional isomer of 4'-keto-2-ene VPA. The sensitivity of the method was also sufficient to detect metabolites of VPA in saliva. The ratio of the levels of (Z)-2-ene VPA to (E)-2-ene VPA was much greater in saliva than in serum, suggesting stereoselective plasma protein binding or transport of these two metabolites. The lower limit of detection for the quantification of VPA in serum or saliva was 2 ng ml-1.
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Affiliation(s)
- K Kassahun
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
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Funke PT, Ivashkiv E, Arnold ME, Cohen AI. Determination of pravastatin sodium and its major metabolites in human serum/plasma by capillary gas chromatography/negative ion chemical ionization mass spectrometry. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1989; 18:904-9. [PMID: 2508807 DOI: 10.1002/bms.1200181010] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A capillary gas chromatography/negative ion chemical ionization mass spectrometry method has been developed to measure pravastatin sodium, an anti-hypercholesterolemic agent, and two of its major metabolites in human serum. Injected on a capillary column, derivatized pravastatin sodium and the two, metabolites were detected at levels of 0.5 pg microliters-1 injected with a signal-to-noise ratio of 3 to 1. The limit of detection was 0.3 ng ml-1 serum of each compound with 95% confidence using a weighted linear regression analysis. Prior to analysis, samples were purified on 200 mg C18 solid-phase extraction columns and derivatized with pentafluorobenzyl bromide and N,O-bis-(trimethylsilyl)-trifluoroacetamide. An excess of pentafluorobenzyl bromide was removed by reaction with propionic acid.
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Affiliation(s)
- P T Funke
- Department of Analytical Research and Development, Squibb Institute for Medical Research, Princeton, New Jersey 08540
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Malle E, Gleispach H, Kostner GM, Leis HJ. Isotope dilution gas chromatography-mass spectrometry for the study of eicosanoid metabolism in human blood platelets. JOURNAL OF CHROMATOGRAPHY 1989; 488:283-93. [PMID: 2654162 DOI: 10.1016/s0378-4347(00)82953-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Stable isotope dilution gas chromatography-mass spectrometry provides one of the most important techniques for the quantitative measurement of eicosanoids. This technique was applied to the quantitation of hydroxyeicosatetraenoic acids, hydroxyheptadecatrienoic acid, thromboxane B2 and prostaglandin F2 alpha formed during platelet aggregation after stimulation of gel-filtered platelets with thrombin (0.25 U/ml) or collagen (2 micrograms/ml). Similar amounts of hydroxyheptadecatrienoic acid and thromboxane B2 were found after platelet activation. The ratio of formation of 12-hydroxyeicosatetraenoic acid to thromboxane B2 varied from donor to donor. Only small amounts of prostaglandin F2 alpha (up to 200 pg per 2.0.10(8) platelets) and basic values of 15-hydroxyeicosatetraenoic acid (up to 100 pg per 2.0.10(8) platelets) were measured using gas chromatography with negative ion chemical ionization mass spectrometry. In addition, different stable isotope dilutions were prepared and are discussed in detail.
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Affiliation(s)
- E Malle
- Institute of Medical Biochemistry, University of Graz, Austria
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14
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Fischer S. Analysis of eicosanoid formation in humans by mass spectrometry. ADVANCES IN LIPID RESEARCH 1989; 23:199-217. [PMID: 2698053 DOI: 10.1016/b978-0-12-024923-7.50009-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- S Fischer
- Medizinische Klinik Innenstadt der Universität München, Federal Republic of Germany
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15
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Hughes H, Nowlin J, Gaskell SJ, Parr VC. Selected reaction monitoring during gas chromatography/mass spectrometry of eicosanoids. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1988; 16:409-13. [PMID: 2853985 DOI: 10.1002/bms.1200160180] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Gas chromatography/electron capture negative ion mass spectrometry of eicosanoids, as pentafluorobenzyl (PFB) ester, methyl oxime (where applicable), trimethylsilyl (TMS) ether derivatives, is reported using a double-focusing instrument of trisector configuration. Sub-picogram detection limits were observed for prostaglandins E1, E2 and F2 alpha during selected ion monitoring (SIM) of [M-PFB]- ions. Selected reaction monitoring (SRM) of [M-PFB]-----[M-PFB-TMSOH]-, occurring in the first field-free region, was of modest sensitivity, reflecting the stability of the [M-PFB]- ions. The leukotriene B4 (LTB4) derivative was successfully analyzed by SIM at the low-picogram level. In this instance, the fragmentation [M-PFB]-----[M-PFB-TMSOH] occurred in high yield in the first field-free region. The advantageous improvement in selectivity of detection that may be achieved with SRM was evident during the analysis of a serum extract for LTB4.
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Affiliation(s)
- H Hughes
- Center for Experimental Therapeutics, Baylor College of Medicine, Houston, Texas 77030
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16
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Hadley JS, Fradin A, Murphy RC. Electron capture negative ion chemical ionization analysis of arachidonic acid. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1988; 15:175-8. [PMID: 3130114 DOI: 10.1002/bms.1200150309] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A highly sensitive (subpicomole level) and structural specific method for the analysis of arachidonic acid esterified to complex glycerophospholipids has been developed using combined capillary gas chromatography and mass spectrometry. The methodology is based upon the formation of the pentafluorobenzyl ester of arachidonic acid, which is efficiently ionized using electron capture negative ion chemical ionization conditions to yield an abundant carboxylate anion at m/z 301. Quantification is carried out following hydrolysis of the complex glycerophospholipid in the presence of a known amount of (2H8) arachidonic acid. The use of this method is illustrated by the quantification of arachidonic acid within the glycerophospholipid classes isolated from resident peritoneal macrophage cells isolated from HS mice.
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Affiliation(s)
- J S Hadley
- Department of Pharmacology, University of Colorado Health Sciences Center, Denver 80262
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17
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de Jong AP, Kok RM, Cramers CA, Wadman SK, Haan E. A new method for the determination of L-dopa and 3-O-methyldopa in plasma and cerebrospinal fluid using gas chromatography and electron capture negative ion mass spectrometry. Clin Chim Acta 1988; 171:49-61. [PMID: 3127089 DOI: 10.1016/0009-8981(88)90290-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
L-3-(3,4-Dihydroxyphenyl)alanine (DOPA) and its 3-O-methyl metabolite (OMD) were measured in plasma and cerebrospinal fluid by a new assay which combines N,O-acetylation of amino acids in aqueous media, preparation of pentafluorobenzyl esters under anhydrous conditions, and analysis by gas chromatography-electron capture negative ion mass spectrometry. The N,O-acetyl, carboxy-PFB derivatives gave abundant carboxylate anions ([M-CH2C6F5]-) which were suitable for sensitive analysis using selected ion monitoring. Plasma and CSF samples were sufficiently purified by a simple organic solvent extraction. Analytical recovery for DOPA was 100.2 +/- 3.7% at the level of 100 nmol/l. Analysis of DOPA in plasma was performed with a relative standard deviation of 5%. The limit of quantitation in plasma and CSF was at the sub-nmol/l level. In healthy adults, DOPA concentration in plasma was 9.0 +/- 2 nmol/l (n = 11) and in CSF 3.5 +/- 0.9 nmol/l (n = 9). The concentration of OMD in plasma was 99.1 nmol/l (pool of 24 samples) and 15.3 nmol/l in CSF (pool of 12 samples). Measurement of 5-[2H]DOPA and 5-[2H]OMD in plasma of a healthy individual who had been orally loaded with 3,5-[2H2]tyrosine (150 mg kg body wt) was possible for several hours after the load.
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Affiliation(s)
- A P de Jong
- Department of Pediatrics, Free University Hospital, Amsterdam, The Netherlands
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Shindo N, Saito T, Murayama K. Rapid quantification of 11 prostanoids by combined capillary column gas chromatography and negative ion chemical ionization mass spectrometry: application to prostanoids released from normal human embryonic lung fibroblasts WI38 in a culture medium. BIOMEDICAL & ENVIRONMENTAL MASS SPECTROMETRY 1988; 15:25-32. [PMID: 3349205 DOI: 10.1002/bms.1200150105] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The rapid and simultaneous quantification of 11 prostanoids has been carried out with a short-capillary gas chromatograph and negative ion chemical ionization (ammonia) mass spectrometer. The methoxime-trimethylsilyl ether-pentafluorobenzyl esters (MO-TMS-PFB) of nine prostanoids, PGA1, PGA2, PGB1, PGB2, PGD2, PGE1, PGE2, 6-oxo-PGF1 alpha and TXB2 and the TMS-PFB of two prostanoids, PGF1 alpha and PGF2 alpha, were separated in less than 5.5 min on a bonded OV-1 capillary column 0.25 mm i.d. x 6 m (0.15 micron thickness) using hydrogen as a carrier gas. PGD2, PGE2, PGF2 alpha, 6-oxo-PGF1 alpha and TXB2 were quantified up to 2.5 fmol injected (0.1 pmol derivatized) and both PGA2 and PGB2 up to 25 fmol injected (1 pmol derivatized). In order to maintain the stability of the prostanoids containing a carbonyl group, such as TXB2 during the purification and derivatization steps of biological materials, methyl acetate was used in place of methyl formate as an eluant for Sep-Pak C18 purification. Normal human embryonic lung fibroblasts W138 (5.63 x 10(5) cells in a log phase) produced: PGA2 15.28, PGB2 13.48, PGD2 7.95, PGE1 2.62, PGE2 177.76, PGF2 alpha 25.14, 6-oxo-PGF1 alpha 27.33 and TXB2 61.00 pmol in 10 ml of Eagle minimal essential medium.
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Affiliation(s)
- N Shindo
- Division of Biochemical Analysis, Juntendo University, School of Medicine, Tokyo, Japan
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Hubbard HL, Eller TD, Mais DE, Halushka PV, Baker RH, Blair IA, Vrbanac JJ, Knapp DR. Extraction of thromboxane B2 from urine using an immobilized antibody column for subsequent analysis by gas chromatography-mass spectrometry. PROSTAGLANDINS 1987; 33:149-60. [PMID: 3588968 DOI: 10.1016/0090-6980(87)90002-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This paper describes an antibody affinity (immunoaffinity) column which, in one step, extracts and sufficiently purifies urinary thromboxane B2 (TXB2) for quantitative analysis by high resolution gas chromatography-negative ion chemical ionization-selected ion monitoring-mass spectrometry (HRGC-NICI-SIM-MS). Polyclonal TXB2 antibody from rabbit was partially purified using immobilized Staphylococcus aureus Protein A. The purified IgG fraction was then immobilized using an N-hydroxysuccimidyl silica gel. The resulting matrix bound 570 ng TXB2 per ml of gel. TXB2 was quantitatively eluted with acetonitrile-water (19:1). Columns constructed from the gel could be used repeatedly since binding capacity was reconstituted using 0.01 M phosphate buffer (pH 7.4) with no apparent loss of activity. Using these columns, urinary TXB2 was sufficiently purified in one step such that in subsequent analysis by HRGC-NICI-SIM-MS interference free chromatograms were observed.
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Affiliation(s)
- H Traitler
- Nestlé Research Center, Nestec Ltd., Lausanne, Switzerland
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Kaykaty M, Weiss G, Barbalas M, Duke P. Metabolism of the synthetic prostaglandin alfaprostol in cows, pigs, and rats. Drug Metab Rev 1987; 18:303-29. [PMID: 3330519 DOI: 10.3109/03602538708998310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- M Kaykaty
- Animal Health and Nutrition Department, Hoffmann-La Roche Inc., Nutley, New Jersey 07110
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22
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Matsuda H, Kuzuya T, Kamada T, Tada M, Matsuura K. Negative-ion chemical-ionization mass spectrometry of eicosanoids and its application to quantitation of prostacyclin synthesis in vascular tissue. JOURNAL OF CHROMATOGRAPHY 1986; 374:347-53. [PMID: 3514646 DOI: 10.1016/s0378-4347(00)83290-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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23
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Wills RJ, O'Leary A, Givens SV, Scheinbaum ML. Trimoprostil plasma concentration-gastric acid inhibition relationships in duodenal ulcer patients. J Clin Pharmacol 1986; 26:48-54. [PMID: 3950051 DOI: 10.1002/j.1552-4604.1986.tb02902.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The effect of single 0.25 mg, 0.75 mg, 1.5 mg, and 3.0-mg oral doses of trimoprostil and placebo on the inhibition of meal-stimulated gastric acid secretion was investigated in duodenal ulcer patients. Drug and placebo were administered in a double-blind, randomized, crossover study under fasting conditions. A bactopeptone meal was administered 30 minutes after dosing. Gastric acid output was measured by intragastric titation (pH 5.5) and trimoprostil plasma concentrations were measured by a specific gas chromatography-negative chemical ionization-mass spectrometric method. Meal-stimulated gastric acid secretion was significantly reduced when compared to placebo for one hour after 0.25 mg, 1.5 hours after 0.75 mg, and for 2.5-3.0 hours after both 1.5 mg and 3.0 mg doses. The maximal inhibition of gastric acid ranged from 65% reduction after 0.75 mg to 74% after 1.5 mg to 82% after 3.0-mg doses. Trimoprostil was rapidly absorbed and eliminated; terminal elimination half-life ranged from 21 to 45 minutes. Both maximum concentration and area under the plasma concentration-time curve increased proportionately with an increase in the dose. The concentration-effect data at a given dose were simultaneously fit to a pharmacokinetic/pharmacologic effect model. An IC50 (plasma concentration needed to elicit a 50% inhibition effect) value of 0.2 ng/mL was observed at doses of 0.75 mg to 3.0 mg. Overall, trimoprostil was effective in inhibiting acid output in a dose-related manner in duodenal ulcer patients.
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Lawson JA, Brash AR, Doran J, FitzGerald GA. Measurement of urinary 2,3-dinor-thromboxane B2 and thromboxane B2 using bonded-phase phenylboronic acid columns and capillary gas chromatography--negative-ion chemical ionization mass spectrometry. Anal Biochem 1985; 150:463-70. [PMID: 4091270 DOI: 10.1016/0003-2697(85)90536-6] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The use of bonded-phase phenylboronic acid columns to selectively extract 2,3-dinor-thromboxane B2 and thromboxane B2 from urine is reported. The compounds were first derivatized as the methoxime and then applied to the phenylboronic acid columns. Subsequent purification by thin-layer chromatography and derivatization to the pentafluorobenzyl ester, trimethylsilyl ether followed by capillary gas chromatography-negative-ion chemical ionization mass spectrometry, monitoring specific ions, allows quantitation in the low-picogram/milliliter range. In healthy male volunteers, the median excretions of 2,3-dinor-thromboxane B2 and thromboxane B2 were 10.3 ng/h (range, 4.5-24 ng/h) and 2.8 ng/h (range, 0.5-7.3 ng/h), respectively. The method offers a noninvasive, specific approach to the study of thromboxane synthesis and platelet function in man. It is much less labor intensive than currently available methods employing electron-impact chromatography-mass spectrometry.
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25
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Meese CO, Fischer C, Thalheimer P, Fürst O. Measurement of thromboxane B2 in human urine by isotope dilution and negative ion chemical ionization mass spectrometry. BIOMEDICAL MASS SPECTROMETRY 1985; 12:554-9. [PMID: 2932184 DOI: 10.1002/bms.1200120919] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A highly sensitive and specific assay for the quantification of thromboxane B2 (TXB2)(1) in human urine is described. The method is based on the use of low-blank (1H less than or equal to 0.2%) tetradeuterated internal standard 2 (18, 18, 19, 19-2H4-thromboxane B2), whose chemical synthesis is reported. After purification and high-performance liquid chromatography (HPLC) samples are derivatized to give an open-chain derivative of thromboxane B2, the methoxime pentafluorobenzyl ester tris(trimethylsilyl) ether (TXB2-MO-PFB-TMS3), most suitable for negative ion chemical ionization mass spectrometry. In the selected ion monitoring mode limits of detection per injection for pure standards and biological samples of 10 pg and 30 pg, respectively, are established. Normal urinary excretion of 1 in humans is 37-112 ng/24 h (n = 12).
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26
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de Silva JA. Analytical strategies for therapeutic monitoring of drugs in biological fluids. JOURNAL OF CHROMATOGRAPHY 1985; 340:3-30. [PMID: 3894401 DOI: 10.1016/0378-4347(85)80193-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Therapeutic drug monitoring can involve quantitation in either microgram, nanogram or picogram concentrations present in a complex biological matrix (whole blood, urine or tissue). The chemical structure of a compound influences not only the analytical method best suited to its quantitation, but also its acid/base character (pKa) and its extractability. The dose administered, the bioavailability of the dosage form, and the pharmacokinetic profile of the drug govern the circulating concentrations of either the parent drug and/or its metabolites present in vivo, and dictate the ultimate sensitivity and specificity required of the analytical method. The degree of sample preparation required is dependent on the analytical method used (gas--liquid chromatography, thin-layer chromatography, high-performance liquid chromatography) and on the tolerance of the specific type of detection system to contamination. Factors leading to compound losses during sample preparation (adsorption, stability) are critical at low concentrations and can adversely affect the reliability of an assay, therefore maximizing the overall recovery of the assay is essential not only for high sensitivity but also for good precision and accuracy. Therefore, the criteria to be used in sample preparation should aim to optimize all of the above factors in the overall development of a reliable and validated method for the compound suitable for use in clinical therapeutic monitoring.
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27
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Rubio F, Garland WA. Determination of acetyltrimoprostil and its metabolite trimoprostil in human or dog plasma by gas chromatography-negative-ion chemical ionization mass spectrometry. JOURNAL OF CHROMATOGRAPHY 1985; 339:313-20. [PMID: 4008571 DOI: 10.1016/s0378-4347(00)84658-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A sensitive and specific procedure is described for the determination of the antisecretory prostaglandin acetyltrimoprostil and its metabolite trimoprostil in human or dog plasma using gas chromatography--negative-ion chemical ionization mass spectrometry (GC--NICI-MS). Trideuterated analogues of both compounds are added to plasma as the internal standards. The plasma is extracted at pH 7.3 with benzene--dichloromethane (9:1), and the residue of the organic extract is reacted at room temperature with pentafluorobenzyl bromide in the presence of 18-crown-6-ether and potassium acetate. The derivatives are reconstituted in heptane, and appropriate aliquots are analyzed by GC--NICI-MS with selected-ion monitoring of the intense (M--C6F5CH2)- fragment ions of acetyltrimoprostil (m/z 419), trimoprostil (m/z 377), and their respective trideuterated analogues (m/z 422 and m/z 380, respectively). Quantitation of an experimental plasma sample is based on a comparison of the m/z 419 versus m/z 422 and m/z 377 versus m/z 380 ion ratios in each sample to that obtained from the analysis of drug-free plasma fortified with various amounts of both protio compounds, and a fixed amount of each trideuterated internal standard. The limit of quantitation of the assay for human plasma is 0.2 ng ml-1 with mean relative standard deviations at this concentration of 15.5% and 9.7% for acetyltrimoprostil and trimoprostil, respectively.
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28
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Krause W, Jakobs U, Schulze PE, Nieuweboer B, Hümpel M. Development of antibody-mediated extraction followed by GC/MS (antibody/GC/MS) and its application to iloprost determination in plasma. PROSTAGLANDINS, LEUKOTRIENES, AND MEDICINE 1985; 17:167-82. [PMID: 3885265 DOI: 10.1016/0262-1746(85)90104-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A new analytical principle has been developed combining the features of both radioimmunoassay and GC/MS. Its application in eicosanoid analysis was tested with the prostacyclin analogue, iloprost. The iloprost antibody, generally employed in RIA measurements, was coupled to Sepharose 4B and used as stationary phase for extraction of the drug. Variations in recovery were corrected by using deuterated iloprost as an internal standard. The samples were derivatized and quantitated by negative-ion chemical ionization-mass spectrometry. Reproducibility was 2.3 % at the 50 pg/ml level and the limit of detection was 5 pg for 1 ml samples. With plasma volumes of up to 20 ml, 0.25 pg/ml could be determined. Antibody/GC/MS proved superior to radioimmunoassay due to its higher specificity and sensitivity and superior to GC/MS with conventional clean-up procedures because of a higher sample capacity.
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Cosulich DB, Perkinson NA, Batra VK. Capillary gas chromatographic-mass spectrometric analysis of 15-deoxy-16-hydroxy-16-vinylprostaglandin E2. J Pharm Sci 1985; 74:76-8. [PMID: 3981424 DOI: 10.1002/jps.2600740120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A new topically active antihypertensive agent, the methyl ester of 15-deoxy-16-hydroxy-16-vinylprostaglandin E2 (1), rapidly hydrolyzes in blood to the carboxylic acid 2, which also has antihypertensive activity. A capillary gas chromatographic-mass spectrometric method is described for measuring 2 in human plasma or serum at expected experimental blood levels of 75-1500 pg/mL. The assay is based on selected-ion monitoring of the carboxylate anion formed from negative ion chemical ionization of the trimethylsilylpentafluorobenzyl ester of 2, using a trideuterated analogue of 2 as internal standard. The method has been used to analyze samples from subjects following topical application of 1-2 mg of 1. Sample preparation included isolation from 1 mL of plasma or serum and purification of the ester derivative with C18 cartridges, followed by a two-step trimethylsilylation.
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Abstract
The influence of food on the bioavailability of trimoprostil , a new antiulcer prostaglandin E2 derivative, was investigated in healthy male volunteers in four separate studies. Doses of 0.75, 1.5, and 3.0 mg were administered orally in both the presence and absence of food followed by serial blood sampling through 24 hours. Plasma trimoprostil concentrations were determined by a gas chromatograph-negative chemical ionization-mass spectrometric method for pharmacokinetic evaluation. Food decreased the absorption rate of trimoprostil as indicated by a later tmax (P less than 0.01) and corresponding lower Cmax at each dose. However, the food effect on tmax diminished as the dose increased. Although Cmax was reduced, food did not alter the extent of absorption, indicated by similar AUC (P greater than 0.05) between fed and fasted states. Both Cmax and AUC increased proportionately with an increase in dose. The harmonic mean half-lives of elimination were similar (P greater than 0.05) across all doses and ranged from 27 to 55 minutes.
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Waddell KA, Barrow SE, Robinson C, Orchard MA, Dollery CT, Blair IA. Quantitative analysis of prostanoids in biological fluids by combined capillary column gas chromatography negative ion chemical ionization mass spectrometry. BIOMEDICAL MASS SPECTROMETRY 1984; 11:68-74. [PMID: 6722282 DOI: 10.1002/bms.1200110205] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An assay for the quantitative analysis of six biologically important prostanoids based on combined gas chromatography negative ion chemical ionization mass spectrometry has been developed. Prostanoids were extracted from biological fluids by liquid chromatography on Sep-Pak cartridges and converted to pentafluorobenzyl ester derivatives. Samples were injected on capillary column by the splitless technique and injections were made in a high boiling hydrocarbon solvent (n-dodecane) in order to minimize chromatographic run times. Quantification was carried out using selected ion monitoring of the appropriate [M-pentafluorobenzyl]- anion. The assay has been used for profiling cyclooxygenase metabolites of arachidonic acid in guinea pig lung perfusate after induction of anaphylaxis and platelet rich plasma after collagen-stimulated aggregation.
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Chapter 3. Gas chromatography. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0167-7306(08)60212-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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33
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Hulshoff A, Lingeman H. Derivatization reactions in the gas—liquid chromatographic analysis of drugs in biological fluids. J Pharm Biomed Anal 1984; 2:337-80. [PMID: 16867717 DOI: 10.1016/0731-7085(84)80040-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Alkylation, acylation, silylation and other derivatization reactions applied to the gas chromatographic analysis of drugs in biological matrices are reviewed. Reaction conditions are discussed in relation to reaction mechanisms. Detector-oriented labelling of drugs, and derivatization with chiral reagents for the separation of enantiomers are surveyed. Data on the sample clean-up, derivatization and GLC analysis of more than 300 drugs and related compounds are listed.
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Affiliation(s)
- A Hulshoff
- Department of Analytical Pharmacy, University of Utrecht, Pharmaceutical Laboratory, Catherijnesingel 60, 3511 GH Utrecht, The Netherlands
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Wills RJ, Rees MM, Rubio F, Gibson DM, Givens S, Parsonnet M, Gallo-Torres HE. Influence of antacids on the bioavailability of trimoprostil. Eur J Clin Pharmacol 1984; 27:251-2. [PMID: 6499906 DOI: 10.1007/bf00544055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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35
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Strife RJ, Murphy RC. Preparation of pentafluorobenzyl esters of arachidonic acid lipoxygenase metabolites. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0378-4347(00)83309-5] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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36
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Waddell KA, Blair IA, Wellby J. Combined capillary column gas chromatography negative ion chemical ionization mass spectrometry of prostanoids. ACTA ACUST UNITED AC 1983. [DOI: 10.1002/bms.1200100207] [Citation(s) in RCA: 77] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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37
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Fischer S, Scherer B, Weber PC. Prostacyclin metabolism in adults and neonates. Urinary profiles of 6-ketoprostaglandin F1 alpha and 2,3-dinor-6-ketoprostaglandin F1 alpha studied by gas chromatography-mass spectrometry. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 750:127-33. [PMID: 6337642 DOI: 10.1016/0005-2760(83)90211-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Metabolism of endogenous prostacyclin was studied in adults and neonates by measuring urinary levels of 6-ketoprostaglandin F1 alpha (spontaneous hydrolysis product) and 2,3-dinor-6-ketoprostaglandin F1 alpha (enzymatically formed by beta-oxidation). Quantification of prostanoids was achieved by capillary gas chromatography-mass spectrometry using the stable isotope dilution technique. Purification of the urinary lipid extract included silicic acid column chromatography and reverse- and straight-phase high-pressure liquid chromatographies. Accuracy of the method was proven by recovery experiments for both metabolites. Partial mass spectra of endogenous 6-ketoprostaglandin F1 alpha and 2,3-dinor-6-ketoprostaglandin F1 alpha were obtained from urine samples. In neonates (third day of life, n - 5 pooled urines) levels of 2,3-dinor-6-ketoprostaglandin F1 alpha (0.28 +/- 0.18 ng/ml) were much lower than those of 6-ketoprostaglandin F1 alpha (2.13 +/- 1.10 ng/ml), indicating low beta-oxidation activity at high prostacyclin formation. In adults (n = 7), levels of 2,3-dinor-6-ketoprostaglandin F1 alpha (0.27 +/- 0.21 ng/ml) and levels of 6-ketoprostaglandin F1 alpha (0.20 +/- 0.11 ng/ml) were about the same, indicating relatively high beta-oxidation at low prostacyclin formation. Values are expressed as mean +/- S.D.
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Chapter 1 The prostaglandins and essential fatty acids. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/s0167-7306(08)60533-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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39
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Waddell K, Robinson C, Orchard M, Barrow S, Dollery C, Blair I. Quantitative analysis of arachidonic acid metabolites in complex biological fluids using capillary gas chromatography/negative ion chemical ionisation mass spectrometry. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0020-7381(83)87071-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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40
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Wood PL. A selected ion monitoring assay for dopamine and its metabolites using negative chemical ionization. BIOMEDICAL MASS SPECTROMETRY 1982; 9:302-6. [PMID: 7126763 DOI: 10.1002/bms.1200090706] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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41
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Barrow SE, Waddell KA, Ennis M, Dollery CT, Blair IA. Analysis of picomolar concentrations of 6-oxo-prostaglandin F1 alpha in biological fluids. J Chromatogr A 1982; 239:71-80. [PMID: 7096507 DOI: 10.1016/s0021-9673(00)81969-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A highly sensitive and specific assay for the quantitation of 6-oxo-prostaglandin F1 alpha, the stable hydrolysis product of prostacyclin, is described. The method involves the addition of [3,3',4,4'-2H4]-6-oxo-prostaglandin F1 alpha as internal standard, extraction from biological fluids using muBondapak C18 reversed-phase Sep-Paks, and preliminary purification by normal-phase chromatography. Following conversion to the methoxime, tris-trimethylsilyl, pentafluorobenzyl derivative, samples were analysed using combined capillary column gas chromatography negative ion chemical ionisation mass spectrometry. Fragments ions at m/z 614 (1H) and 618 (2H) [M-C7H2F5]- were monitored for quantitation. This method was used for the measurement of endogenous levels of 6-oxo-prostaglandin F1 alpha in human urine and for the determination of prostacyclin release from rat peritoneal mast cells and from rat aortic rings incubated in human plasma.
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Blair IA, Barrow SE, Waddell KA, Lewis PJ, Dollery CT. Prostacyclin is not a circulating hormone in man. PROSTAGLANDINS 1982; 23:579-89. [PMID: 7051184 DOI: 10.1016/0090-6980(82)90118-6] [Citation(s) in RCA: 222] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A highly specific stable isotope dilution assay for plasma 6-oxo-prostaglandin F1 alpha has been developed. The method employs capillary column gas chromatography coupled with negative ion chemical ionisation mass spectrometry. The limit of sensitivity of the assay is 0.5 pg.m1(-1). Concentrations of 6-oxo-prostaglandin F1 alpha in the plasma of 20 healthy volunteers determined by this assay were all below 3 pg.m1(-1). The levels were much lower than any previously reported and confirms that prostacyclin is not a circulating hormone in man under normal physiological conditions.
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Chapter 13 Biomedical applications of the electron-capture detector. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/s0301-4770(08)60137-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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