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Single‐step modified QuEChERS for determination of chlorothalonil in shallot ( Allium ascalonicum ) using GC‐μECD and confirmation via mass spectrometry
Author(s) -
Rahman Md. Musfiqur,
Park JongHyouk,
Abd ElAty A. M.,
Choi JeongHeui,
Bae Hey Ree,
Yang Angel,
Park Ki Hun,
Shim JaeHan
Publication year - 2013
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.2808
Subject(s) - quechers , chemistry , chromatography , chlorothalonil , extraction (chemistry) , gas chromatography–mass spectrometry , mass spectrometry , detection limit , residue (chemistry) , electron capture detector , calibration curve , gas chromatography , matrix (chemical analysis) , pesticide residue , pesticide , organic chemistry , agronomy , biology
A single extraction method was developed for chlorothalonil in shallot using gas chromatography with an electron capture detector (GC‐μECD). Samples were extracted with single‐step modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method using ethyl acetate as an extraction solvent. Significant matrix effects were observed, and the calibration curve was constructed from the matrix. The linearity of the analytical response across the studied range of concentrations (0.01–1.00 mg/L) was excellent, obtaining a correlation coefficient ( r 2 ) of 0.996. >0.996. Recovery studies were carried out on spiked shallot blank samples, at two concentration levels (0.4 and 2.0 mg/kg) with three replicates performed at each level. Mean recoveries of 97.2–104.9% with RSDs of 1.3–2.7% were obtained. The method is demonstrated to be suitable for the determination of chlorothalonil in shallot. The dissipation rates of chlorothalonil were described using first‐order kinetics, and its half‐life was 2.8 days. Based on the dissipation pattern of the pesticide residues, the pre‐harvest residue limit (PHRL) was also calculated. Residues were confirmed via mass spectrometry. Copyright © 2012 John Wiley & Sons, Ltd.