Isolation and quantification of cholesterol oxides in dairy products by selected ion monitoring mass spectrometry

1995 ◽  
Vol 62 (1) ◽  
pp. 101-113 ◽  
Author(s):  
Jacob H. Nielsen ◽  
Carl Erik Olsen ◽  
Christina Duedahl ◽  
Leif H. Skibsted
Keyword(s):  
Mass Spectrometry ◽  
Dairy Products ◽  
Solid Phase ◽  
Dairy Product ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Cholesterol Oxidation ◽  
Preparative Hplc ◽  
Selected Ion Monitoring ◽  
Limit Of Quantification

SUMMARYA method for isolation, detection and quantification of cholesterol oxidation products based on solid phase extraction in combination with preparative HPLC and gas chromatography–mass spectrometry selected ion monitoring has been developed for dairy products. The isolation procedure had a high recovery and artifact formation was minimal, as shown by isotope labelling. The limits of detection ranged from 0.3 to 35 pg/μl of the isomeric forms of 7-hydroxycholesterol, 20α-hydroxycholesterol, the isomeric forms of cholesterol-5,6-epoxides, cholestanetriol, 25-hydroxycholesterol and 7-ketocholesterol corresponding to a limit of quantification of 2–6 ng oxysterol/g lipid in the dairy product, depending on the nature of the cholesterol oxidation product.

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.

The Determination of Eight Pesticides in Panax notoginseng of Chinese Traditional Medicine Using Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry

2012 ◽  
Vol 485 ◽  
pp. 68-71
Author(s):  
Na Wu ◽  
Yu Da Zhang ◽  
Wei Liu ◽  
Ping Yi ◽  
Ze Feng Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Panax Notoginseng ◽  
Gas Chromatography Mass Spectrometry ◽  
Phase Extraction ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Relative Standard

A simple and effective extraction method based on solid-phase extraction (SPE) was developed to determine chlorothalonil, metalaxyl, triadimefon, dimetachlone, procymidone, flumetralin, oxadixyl and iprodione in Panax Notoginseng using gas chromatography-mass spectrometry with selected ion monitoring (GC/MS, SIM). The prepared samples were analysed with GC-MS in the selected ion monitoring mode (SIM) using one target and two or three qualitative ions for each analyte. In the method, hexane - dichloromethane（6:4，v/v）was selected to effectively extract the pesticides from the Panax Notoginseng samples. Solid-phase extraction was carried out using Supelclean ENVI-Carb/NH2 SPE Column with acetonitrile-toluene (3:1, v/v) as the eluted solvent. In the linear range of each pesticide, the correlation coefficient was R2≥0.99. The limit of detection ranged from 0.001 to 0.05 µg.mL-1, average recoveries ranged from 79.80% to 95.00%, with relative standard deviations between 1.96% and 4.32% for all 8 pesticides.They were readily achieved with this method for all tested pesticides.

Simultaneous Analysis of Simple Coumarins and Furocoumarines in Cigarettes by Solid-Phase Extraction with Gas Chromatography-Mass Spectrometry

2017 ◽  
Vol 100 (5) ◽  
pp. 1559-1564 ◽  
Author(s):  
Yang Zheng ◽  
Xiuli Xu ◽  
Fei Yuan ◽  
Meiyi Yao ◽  
Shunli Ji ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Phase Extraction ◽  
Selected Ion Monitoring ◽  
Oasis Hlb ◽  
Coumarin 6

Abstract A sensitive, high-throughput analytical method based on a GC-MS method was established for the simultaneous quantitative determination of two categories of harmful coumarins: simple coumarins (coumarin, 6-methylcoumarin, 7-methoxycoumarin, 3,4-dihydrocoumarin, and 7-ethoxy-4-methylcoumarin) and furocoumarines (psoralen, 8-methoxypsoralen, 5-methoxypsoralen, and trioxysalen). The nine analytes were extracted with ethyl acetate, purified with Oasis HLB solid-phase extraction (SPE) cartridges, and identified and quantitatively determined by GC-MS in selected-ion monitoring mode. The LODs and LOQs of these compounds were in the ranges of 12.5–21.2 and 41.6–70.0 μg/kg, respectively. Average recoveries for the nine analytes ranged from 72.7 to 86.6% atLOQ, 1.5× LOQ, and 2× LOQ spike levels, with RSDs that were typically lower than 5.1%. TheSPE-GC-MS method developed in this study was initially applied to research coumarins in cigarette samples; it proved to be accurate, sensitive, convenient, and practical.

scholarly journals A Novel Application of Natural Peat for Solid-Phase Extraction of Pyrimethanil, Flumetralin, and Kresoxim-Methyl in Water Using Gas Chromatography-Mass Spectrometry

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Alex S. M. S. J. Santos ◽  
Adriano Aquino ◽  
Luciane P. C. Romão ◽  
Sandro Navickiene
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Correlation Coefficients ◽  
Gas Chromatography Mass Spectrometry ◽  
Phase Extraction ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Detection And Quantification

Natural peat was tested for extraction of pyrimethanil, flumetralin, and krexosim-methyl from water, with analysis using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode (SIM). Experiments were carried out at one fortification level (0.1 μg L−1) and resulted in recoveries in the range 41–96%, with RSD values between 6.8 and 12.6% for natural peat as sorbent. Detection and quantification limits ranged from 0.02 to 0.05 μg L−1 and from 0.07 to 0.1 μg L−1, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.07–4.0 μg L−1), with correlation coefficients ranging from 0.9919 to 0.9989. Comparison between peat and commercial sorbents (C18-bonded silica, ENVI-Carb, Florisil, silica gel, ENVI-Carb/LC-NH2) showed better performance of peat sorbent for flumetralin and kresoxim-methyl.

scholarly journals Determination of Ttace Levels of Dichlorprop, Mecoprop, Clofibric Acid, and Naphthylacetic Acid in Soil by Gas Chromatography/Mass Spectrometry with Selected-Ion Monitoring

1996 ◽  
Vol 79 (6) ◽  
pp. 1428-1433 ◽  
Author(s):  
Thomas Heberer ◽  
Hans-Juergen Stan
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase ◽  
Clofibric Acid ◽  
Gas Chromatography Mass Spectrometry ◽  
Aqueous Acetic Acid ◽  
Selected Ion Monitoring ◽  
Sample Extract ◽  
Relative Standard ◽  
Naphthylacetic Acid

Abstract A sensitive analytical method was developed for determining trace levels of dichlorprop, mecoprop, clofibric acid, and naphthylacetic acid in soil samples. The method applies extraction with acetone and aqueous acetic acid followed by solid-phase extraction as the first cleanup step. After target analytes are derivatized with pentafluorobenzyl bromide, they are determined by capillary gas chromatography (GC)/mass spectrometry with selectedion monitoring. Further cleanup of sample extract by gel permeation chromatography prevented the GC system from being contaminated with matrix compounds, although in most cases, it was not necessary. Limits of detection and quantitation as low as 0.1 and 1 ppb, respectively, were achieved. Recoveries of all analytes were >90%, with relative standard deviations of <10%.

Detection of 30 Acidic Herbicides and Related Compounds as Their Pentafluorobenzylic Derivatives Using Gas Chromatography/Mass Spectrometry

1994 ◽  
Vol 77 (6) ◽  
pp. 1587-1604 ◽  
Author(s):  
Thomas Heberer ◽  
Susanne Butz ◽  
Hans-Juergen Stan
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Time Window ◽  
Solid Phase ◽  
Tap Water ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Acidic Herbicides ◽  
Related Compounds

Abstract Thirty phenoxyalkanoic acids, other acidic herbicides, and related compounds were derivatized with pentafluorobenzyl bromide to form their pentafluorobenzylic derivatives. Mass spectra are presented. Determination and detection of the derivatives was performed by capillary gas chromatography (GC)/mass spectrometry. With selected- ion monitoring, an optimized GC method, and appropriate time-window setting, the determination of all compounds could be achieved in a single GC run. The determination of ≤1 pg of the target compounds was achieved using electron-impact ionization in selected-ion monitoring mode. Most of the analytes were extracted from tap water, and recoveries were 80–100% when solid-phase extraction was applied with a carefully selected reversedphase-C18 adsorbent. The method enabled the detection of these contaminants from drinking water at the low nanogram-per-liter level when applying a concentration factor of 10 000.

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