Determination of testosterone and 6β-hydroxytestosterone by gas chromatography–selected ion monitoring–mass spectrometry for the characterization of cytochrome p450 3A activity

1999 ◽  
Vol 734 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Samuel A Testino Jr ◽  
Justyna Ozarowski ◽  
Archie W Thurston ◽  
Richard F Arrendale ◽  
Gabor Patonay
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Cytochrome P450 ◽  
Cytochrome P450 3A ◽  
Selected Ion Monitoring

Simultaneous Determination of Alachlor, Metolachlor, Atrazine, and Simazine in Water and Soil by Isotope Dilution Gas Chromatography/Mass Spectrometry

1989 ◽  
Vol 72 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Lee Q Huang
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Simultaneous Determination ◽  
Isotope Dilution ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry

Abstract A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of 15N,13C-alachlor and 2H5-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples.

scholarly journals Determination of Mammalian Lignans in Biological Samples by Modified Gas Chromatography/Mass Spectrometry

2007 ◽  
Vol 90 (3) ◽  
pp. 641-646 ◽  
Author(s):  
Ajay Bommareddy ◽  
Bhanu L Arasada ◽  
Duane P Mathees ◽  
Chandradhar Dwivedi
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Gas Chromatography Mass Spectrometry ◽  
Serum Samples ◽  
Selected Ion Monitoring ◽  
Beneficial Effects ◽  
Chromatography Mass Spectrometry ◽  
Flaxseed Meal

Abstract Lignans in flaxseed have been part of the human diet for centuries. In 1955, the isolation and structure of the lignan derivative secoisolariciresinol diglucoside (SDG) was reported. The biological role of SDG and mammalian lignan metabolites enterodiol and enterolactone was initially reported 20 years later. Experimental evidences showed the beneficial effects of lignans on breast, colon, and thyroid cancer. A modified gas chromatography/mass spectrometry (GC/MS) assay was developed for lignans in serum and colon samples of rats fed flaxseed meal. The method developed for the analysis of metabolites involves extraction and derivatization of samples and quantitative analysis by selected ion monitoring using GC/MS. The levels of lignan metabolites enterodiol and enterolactone were determined to be 0.013 and 0.23 M in serum samples and 0.008 and 1.63 M in colon samples.

scholarly journals New Methodologies for Qualitative and Semi-Quantitative Determination of Carbon-Centered Free Radicals in Cigarette Smoke Using Liquid ChromatographyTandem Mass Spectrometry and Gas Chromatography-Mass Selective Detection

2010 ◽  
Vol 24 (2) ◽  
pp. 58-71 ◽  
Author(s):  
AR Gerardi ◽  
WM Coleman
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Free Radicals ◽  
Cigarette Smoke ◽  
Selective Detection ◽  
Selected Ion Monitoring ◽  
Relative Quantitation ◽  
Liquid Chromatography Tandem Mass ◽  
New Methodologies

AbstractSeveral approaches were explored to develop a high throughput procedure for relative determination of 14 different carbon-centered free radicals, both acyl and alkylaminocarbonyl type, in cigarette smoke. Two trapping procedures using 3-cyano-2,2,5,5-tetramethyl-1-pyrrolidinyloxy, or 3-cyanoproxyl radical (3-CNP) were designed for this study: a) trapping in solution and b) trapping on a solid support which was a Cambridge filter pad. Fresh whole smoke and vapor phase smoke from mainstream cigarette smoke from Kentucky Reference Cigarettes 2R4F, as partitioned via an unadulterated Cambridge filter pad, were transferred into each trapping system in separate experiments. The 3-CNP coated Cambridge filter pad approach was shown to be superior to the impinger procedure as described in this study. Gas chromatography coupled with mass selective detection (GC-MS) was employed for the first time as an alternate means of detecting several relatively highly concentrated radical adducts. Liquid chromatography tandem mass spectrometry (LC-MS/MS) with precursor ion monitoring and selected ion monitoring (SIM) was used for detecting the large array of radicals, including several not previously reported: formyl, crotonyl, acrolein, aminocarbonyl, and anilinocarbonyl radicals. Relative quantitation was achieved using as external calibration standards of 4-(1-pyrrolidino)benzaldehyde and nicotine. It was determined that the yield of carbon-centered free radicals by reference cigarette 2R4F was approximately 265 nmoles/cigarette at 35 mL puff/60 sec interval/2 sec duration smoking conditions.

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