A multiresidue method for the determination of 109 pesticides in rice using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) sample preparation method and gas chromatography/mass spectrometry with temperature control and vacuum concentration

Abstract

A rapid, specific and sensitive multiresidue method based on the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) sample preparation method and gas chromatography with mass spectrometric detection by selected ion monitoring (GC/MS-SIM) has been developed for the routine analysis of 109 pesticides in rice. The method uses one quantification ion and two identification ions. Temperature control during sample preparation helps improve the recovery of thermally labile pesticides such as captan. The method was validated by the analysis of samples spiked at 0.025-0.150 mg/kg in rice matrix. The recoveries of all pesticides were between 80% and 115% with a relative standard deviation of less than 15%. The limit of quantitation (LOQ) for most compounds met the maximum residue limits (MRLs) for pesticides in rice in Korea.

Method for routine screening of pesticides and metabolites in meat based baby‐food using extraction and gas chromatography‐mass spectrometry

“…Previous authors had underlined that the original QuECh-ERS method presented a concentration of the final extract estimated at 1 mg/mL, which was considerate as insufficient for the analytical performance of common apparatus [6,37]. To obtain LOQ of 10 lg/kg, the analyzed concentration must be equal or below this value.…”

“…Then 6 g of anhydrous magnesium sulphate and 1.5 g of anhydrous sodium acetate were added. The mixture was gently and manually shaked during 1 min in ice to minimize heat shock of the most thermolabile pesticides as previously suggested by other authors [37], and then sample was vigorously shaken 3 min. The upper layer of hexane was removed and the tube was centrifuged at 5000 rpm for 1 min.…”

Antimicrobial and Antioxidant Potential of Astragalus psilocentros

“…The hexane extracted part of ethyl acetate fraction was subjected to GC-MS analysis for evaluation of its volatile constituents. The complete chromatogram exhibit presence of at least ten distinct components but by using NIST dictionary we are able to identify just four out of them that are 1,3-bis-(trimethylsiloxy) benzene (r.t. 4 All these components already identified from different plants [22][23][24][25] however we are reporting them first time from this plant. One of the compounds 1,2-benzene dicarboxylic acid, is identified in the flower of Spathodea campanulata and from roots of Plumbago zeylanica L. by GC-MS analysis and reported to show moderate to good antibacterial activity against both gram positive and gram negative bacteria [26][27][28] .…”

“…The ion source temperature was 250 ºC and the MS transfer line temperature was 205 ºC. The electron multiplier voltage (EM voltage) was maintained at 1000 V and the solvent delay of 3 min was employed 22,23 . All the compounds were identified by comparison of their GC retention data and mass spectra with those of pure and authentic samples and also by comparing fragmentation patterns of mass spectra with those stored in the spectrometer data base (NIST 147) and bibliography 24,25 .…”

Current trends in sample preparation for growth promoter and veterinary drug residue analysis

“…Upon shaking and centrifugation, an aliquot of the organic phase is subjected to further purification using dispersive-SPE, which entails mixing sorbents with the extract. The approach is very flexible, and since its development there have been several modifications to the technique depending on residues, matrices, instrumentation, and analyst preferences [16,17,[62][63][64][65][66][67][68][69][70][71][72]. The approach uses very little labware and generates little waste.…”