scholarly journals A Multiresidue Pesticide Monitoring Procedure Using Gas Chromatography/Mass Spectrometry and Selected Ion Monitoring for the Determination of Pesticides Containing Nitrogen, Sulfur, and/or Oxygen in Fruits and Vegetables

2004 ◽  
Vol 87 (5) ◽  
pp. 1224-1236 ◽  
Author(s):  
Gregory E Mercer ◽  
Jeffrey A Hurlbut

Abstract A procedure for the analysis of over 100 pesticides that only contain combinations of carbon, hydrogen, nitrogen, sulfur, and oxygen (i.e., no phosphorous or halogen atoms) has been developed. The procedure employs gas chromatography with a mass selective detector (GC/MSD), electron impact ionization, and selected ion monitoring. This GC/MSD procedure provided lower limits of quantitation and increased confirmational data compared to the traditional element-selective GC procedures that are commonly used for the detection of this “class” of pesticides. These analytical improvements were demonstrated by 26 pesticides that were detected at ng/g levels in a variety of fruit and vegetable matrixes using this procedure; these pesticides were missed by the traditional element-selective GC procedures. Validation of the procedure was performed using acetone extraction with solid-phase extraction cleanup. Twenty representative target pesticides were used to demonstrate repeatability and linearity of the chromatographic response and recovery from fruit and vegetable matrixes.

2000 ◽  
Vol 83 (3) ◽  
pp. 698-713 ◽  
Author(s):  
Julie Fillion ◽  
François Sauvé ◽  
Jennifer Selwyn

Abstract A method is described for the determination of 251 pesticide and degradation product residues in fruit and vegetable samples. Extraction of the sample with acetonitrile is followed by a saltingout step. Co-extractives are removed by passing a portion of the acetonitrile extract through an octadecyl (C18) solid-phase extraction cleanup cartridge and then, in a second cleanup, through a carbon cartridge coupled to an amino propyl cartridge. Determination is by gas chromatography with mass-selective detection in the selected-ion monitoring mode, and by liquid chromatography with post-column reaction and fluorescence detection for N-methyl carbamates. The method has been used for analysis of various fruits and vegetables, such as apple, banana, cabbage, carrot, cucumber, lettuce, orange, pear, pepper, and pineapple. Limits of detection range between 0.02 and 1.0 mg/kg for most compounds. Over 80% of the compounds have a limit of detection of ≤0.04 mg/kg.


1989 ◽  
Vol 72 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Lee Q Huang

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.


2012 ◽  
Vol 485 ◽  
pp. 68-71
Author(s):  
Na Wu ◽  
Yu Da Zhang ◽  
Wei Liu ◽  
Ping Yi ◽  
Ze Feng Wang ◽  
...  

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.


2017 ◽  
Vol 100 (5) ◽  
pp. 1559-1564 ◽  
Author(s):  
Yang Zheng ◽  
Xiuli Xu ◽  
Fei Yuan ◽  
Meiyi Yao ◽  
Shunli Ji ◽  
...  

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Alex S. M. S. J. Santos ◽  
Adriano Aquino ◽  
Luciane P. C. Romão ◽  
Sandro Navickiene

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.


1996 ◽  
Vol 79 (6) ◽  
pp. 1428-1433 ◽  
Author(s):  
Thomas Heberer ◽  
Hans-Juergen Stan

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%.


1994 ◽  
Vol 77 (6) ◽  
pp. 1587-1604 ◽  
Author(s):  
Thomas Heberer ◽  
Susanne Butz ◽  
Hans-Juergen Stan

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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