A rapid and easy multiresidue method for the determination of pesticide residues in vegetables, fruits, and cereals using liquid Chromatography/tandem mass spectrometry.
ABSTRACT The applicability of a rapid and easy multiresidue method for determination of pesticide residues in agricultural products by using liquid chromatography/tandem mass spectrometry (LC/MS/MS) was examined. Pesticide residues were extracted with acetonitrile in a disposable tube using a homogenizer, followed by salting out with anhydrous magnesium sulfate and sodium chloride. The extract was purified with a double-layered cartridge column (graphite carbon black/primary-secondary amine silica gel). After removal of the solvent, the extract was resolved in methanol-water and analyzed with LC/MS/MS. Recovery tests of 99 pesticide residues from 7 agricultural products were performed at 20 and 100 ng/g. Throughout all of the agricultural products tested, 47 pesticides exhibited satisfactory recoveries (70-120%) and relative standard deviations (<20%) at both concentrations. The time for processing of 12 samples to test solutions was approximately 2-3 h. This method could be useful for determination of pesticide residues in agricultural products.
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ABSTRACT: A multi-residue method for simultaneous determination of 41 LC-amenable pesticides in rice, belonging to different chemical classes has been developed in Iran by LC-MS/MS. For the first time the pesticides were analyzed simultaneously in a single run using positive electrospray ionization with multiple reaction monitoring (MRM) after extraction with slightly modified QuEChERS method. The calibration curve for each analyte was linear over the concentration range of 0.02-1.0 μg/g with a correlation coefficient range between 0.993 and 0.999. The LOQ and LOD were .025 μg/g and 0.008 μg/g respectively, for all 41 pesticides and the mean recoveries obtained for three fortification levels (0.025, 0.08 and 0.250 μg/g) were 71-119% with satisfactory precision (RSD<20%). The developed method was used to investigate the occurrence of pesticides in 30 domestic and 30 imported rice samples collected from Tehran market. Five compounds were detected in 11 domestic and 9 imported positive samples in concentration range from 0.032 μg/g to 0.081 μg/g and 0.028 μg/g to 0.074 μg/g, respectively. With the exception of prohibited pesticides, phosphamidon and TCMTB, three permitted pesticides, cinosulfuron, triadimenol and tricyclazole, found in positive rice samples were below MRLs established by Institute of Standards and Industrial Research of Iran (ISIRI).Iranian journal of pharmaceutical research (IJPR) 01/2014; 13(3):927-935. · 0.54 Impact Factor
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ABSTRACT: In this study, a simple, effective, and sensitive method has been developed for the quantitative residue analysis of cyhalofop-butyl and its metabolite cyhalofop acid in water and soil when kept under laboratory conditions. The content of cyholofop-butyl and cyhalofop acid in water and soil was analyzed by first purifying the compounds through liquid-liquid extraction and partitioning followed by Silica gel (adsorption) chromatography. Upon the completion of the purification step the residual levels were monitored through high-performance liquid chromatography (HPLC) using a UV absorbance detector. The recoveries of cyhalofop-butyl from three replicates spiked at two different concentrations ranged from 82.5 to 100.0% and from 66.7 to 97.9% in water and soil, respectively. The limit of detection and minimum detection level of cyhalofop-butyl in water and soil was 0.02 ppm and 10 ng, respectively. The recoveries of cyhalofop acid ranged from 80.7 to 104.8% in water and from 76.9 to 98.1 % in soil. The limit of detection of cyhalofop acid was 0.005 ppm in water and 0.01 ppm in soil, while the minimum detection level was 2 ng both in water and soil. The half-live of cyhalofop-butyl was 4.14 and 6.6 days in water and soil, respectively. The method was successfully applied to evaluate cyhalofop-butyl residues in water and soil applied aj. 30% emulsion, oil in water (EW) product.The Korean Journal of Pesticide Science. 01/2008; 12(4).
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ABSTRACT: A simple and high-throughput multiresidue pesticide analysis method was developed and validated for 219 pesticides in cereals (corn, wheat flour and rice) based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure combined with gas chromatography–triple quadrupole mass spectrometry (GC–MS/MS). Different buffer system (acetate- and citrate-buffered) and sample to solvent ratios (sample amount) were compared in the modified QuEChERS procedure to get better recovery and clean-up results. The limits of quantification (LOQ) ranged between 5 and 50 μg kg−1, and for the majority of the pesticides the LOQ were 5 μg kg−1, which were below the regulatory maximum residue limits. The coefficient of determination (r2) was >0.99 within the calibration linearity range of 2–200 μg kg−1 for the majority of the pesticides. Most recoveries at 5, 10, 20, 50, 100 and 200 μg kg−1 were in the range 70–120% (n = 6) with associated RSDs < 20% indicating satisfactory accuracy.Food Chemistry 02/2015; 169:372–380. · 3.33 Impact Factor