Jyot Gagan, Singh Balwinder
Punjab Agricultural University, Department of Entomology, Pesticide Residue Analysis Laboratory, Ludhiana 141004, Punjab, India.
J AOAC Int. 2017 May 1;100(3):796-803. doi: 10.5740/jaoacint.16-0206. Epub 2017 Jan 28.
An easy and simple analytical method was standardized and validated for the estimation of residues of thiamethoxam and its metabolites in cotton. The samples were extracted with acetonitrile, water, and methanol; diluted with brine solution; partitioned into dichloromethane and ethyl acetate; dried over anhydrous sodium sulfate; and cleaned up by glass column chromatography. Final clear extracts were concentrated under vacuum and reconstituted into HPLC grade acetonitrile, and residues were estimated using an HPLC instrument equipped with a C18 column and photodiode array detector system. Acetonitrile-1% formic acid in HPLC grade water (30 + 70) was used as mobile phase at 0.2 mL/min. Consistent recoveries ranging from 82 to 97% for thiamethoxam and its metabolites were observed when samples were spiked at 0.05-1.0 mg/kg levels. The LOQ of the method was determined to be 0.05 mg/kg. The analytical method was validated in terms of the selectivity, linearity, precision, and accuracy of the detection system.
一种简便的分析方法被标准化并验证用于测定棉花中噻虫嗪及其代谢物的残留量。样品用乙腈、水和甲醇提取；用盐水溶液稀释；分配到二氯甲烷和乙酸乙酯中；用无水硫酸钠干燥；并通过玻璃柱色谱法净化。最终的澄清提取物在真空下浓缩并重新溶解于HPLC级乙腈中，使用配备C18柱和光电二极管阵列检测器系统的HPLC仪器测定残留量。以乙腈-1%甲酸（HPLC级水，30 + 70）作为流动相，流速为0.2 mL/min。当样品添加量为0.05 - 1.0 mg/kg水平时，噻虫嗪及其代谢物的回收率在82%至97%之间。该方法的定量限测定为0.05 mg/kg。该分析方法在检测系统的选择性、线性、精密度和准确度方面进行了验证。
