多壁碳纳米管分散固相萃取-液相色谱串联质谱法测定大米中26种氨基甲酸酯类农药及其代谢产物残留量

Determination of 26 Carbamate Pesticides and Their Metabolites Residues in Rice by Multi-Walled Carbon Nanotubes Dispersion Solid Phase Extraction Coupled with Liquid Chromatography-Tandem Mass Spectrometry

目的:建立多壁碳纳米管分散固相萃取-液相色谱串联质谱法测定大米中26种氨基甲酸酯类农药及其代谢产物残留量的分析方法。方法:大米样品水化后经酸化乙腈提取,多壁碳纳米管净化,C_(18)色谱柱分离,流动相采用2 mmol/L甲酸铵水和2 mmol/L甲酸铵甲醇进行梯度洗脱,电喷雾正离子(ESI^(+))模式电离,多反应监测模式检测,基质标准曲线外标法定量。结果:结果表明,26种农药在0.2-100 ng/mL范围内线性关系良好,相关系数均大于0.999,方法的检出限(S/N=3)为0.01-0.18μg/kg,定量限(S/N=10)为0.03-0.58μg/kg。在1、2μg/kg和20μg/kg 3个添加水平下,26种农药的回收率为87.4%-112.8%,相对标准偏差(n=6)为1.46%-7.22%。结论:该方法操作简便、灵敏度和精密度高、结果准确可靠,适用于大米中氨基甲酸酯类农药及其代谢产物残留量的检测。

Objective:To establish a method for the determination of 26 carbamate pesticides and their metabolites residues in rice by multi-walled carbon nanotubes dispersion solid phase extraction coupled with liquid chromatography-tandem mass spectrometry.Methods:The rice samples were mixed with water,extracted by 1%acetic acid acetonitrile,purified by multi-walled carbon nanotubes,separated by C_(18) column,gradient elution was performed with 2 mmol/L ammonium formate water and 2 mmol/L ammonium formate methanol as mobile phases,ionized by electrospray positive ion(ESI^(+))mode,detected by multiple reaction monitoring(MRM)mode,and quantified by matrix standard curve external standard method.Results:The results showed that the linear relationships of 26 pesticides were good in the range of 0.2-100 ng/mL,and the correlation coefficients were all greater than 0.999.The limits of detection(S/N=3)ranged from 0.01μg/kg to 0.18μg/kg,and the limits of quantitation(S/N=10)ranged from 0.03μg/kg to 0.58μg/kg.The recoveries of 26 carbamate pesticides and their metabolites residues at three spiked levels of 1,2μg/kg and 20μg/kg ranged from 87.4%to 112.8%,and the relative standard deviations(n=6)ranged from 1.46%to 7.22%.Conclusion:The method is simple,sensitive,accurate and reliable,and it is suitable for the determination of carbamate pesticides and their metabolites residues in rice.