Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7600583 | Food Chemistry | 2014 | 8 Pages |
Abstract
Simple extraction and optimised oxidation procedures were developed for the determination of the total residues of imidacloprid and its metabolites (containing the 6-chloropicolyl moiety) in lettuce using a gas chromatography-micro electron capture detector (GC-μECD). Samples were extracted with acetonitrile, and the extract was then evaporated. The remaining residues were dissolved in water and oxidised with potassium permanganate to yield 6-chloronicotinic acid (6-CAN). The acid residues were further dissolved in n-hexane:acetone (8:2, v/v) and then silylated with MSTFA (N-methyl-N-(trimethylsilyl)trifluoroacetamide) to 6-chloronicotinic acid trimethylsilyl ester. Calibration curves were linear over the concentration ranges (0.025-5 μg mLâ1) with a determination coefficient (r2) of 0.991. The limits of detection and quantification were 0.015 and 0.05 mg kgâ1, respectively. Recoveries at two fortification levels ranged between 72.8% and 108.3% with relative standard deviation (RSD) lower than 8%. The method was effective, and sensitive enough to determine the total residues of imidacloprid and its metabolites in field-incurred lettuce samples. The identity of the analyte was confirmed using gas chromatography-tandem mass spectrometry (GC-MS/MS).
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Ah-Young Ko, Md. Musfiqur Rahman, A.M. Abd El-Aty, Jin Jang, Jong-Hyouk Park, Soon-Kil Cho, Jae-Han Shim,