QuEChERS-超高效液相色谱-串联质谱法同时测定枸杞子中65种农药残留

Simultaneous determination of 65 kinds of pesticide residues in Lycium barbarum by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry

目的采用多壁碳纳米管改进的QuEChERS-超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)建立一种能够快速、稳定地同时测定枸杞子中65种农药残留的分析方法。方法样品经粉碎后,加水溶胀,乙腈萃取,多壁碳纳米管净化,Waters Acquity UPLC BEH C18柱(100 mm×2.1 mm,1.7μm)分离,以2 mmol/L醋酸铵水混合溶液(含0.1%甲酸,V/V)-2 mmol/L醋酸铵甲醇混合溶液(含0.1%甲酸,V/V)为流动相进行梯度洗脱,采用电喷雾正离子多反应监测模式进行分段扫描。选择阴性有机枸杞子作为空白基质,基质匹配外标法对65种农药残留进行定量分析。结果65种农药在线性范围内线性关系良好,线性相关系数在0.9962~1.0000之间,方法的检出限为0.5~5.0μg/kg,定量限为1.0~10.0μg/kg,加标回收率为65.9%~117.0%,相对标准偏差为2.9%~13.0%。采用该方法对不同来源的40份枸杞子进行检测,共计检出农药残留39种,占比为60.0%,主要为杀虫剂、杀菌剂、杀螨剂、除草剂,其中克百威、3-羟基克百威、甲胺磷、氧乐果、甲拌磷砜、甲拌磷亚砜6种农药为禁限用农药。检出率最高的为苯醚甲环唑与啶虫脒,两者检出率均为97.5%。不合格率最高的项目为克百威,不合格率达到25%。结论该法准确、灵敏、快速,适用于枸杞子中65种农药残留的检测,对实现枸杞子种植过程管控、日常监管、质量保障具有重要意义。

Objective To establish a rapid and stable method for simultaneous determination of 65 kinds of pesticide residues in Lycium barbarum by improved QuEChERS with multi-walled carbon nanotubes-ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).Methods After sample crushing,water swelling and acetonitrile extraction,the multi-walled carbon nanotubes was used for the purification.Waters Acquity UPLC BEH C 18 column(100 mm×2.1 mm,1.7μm)was used for separation,and a gradient elution was carried out using 2 mmol/L ammonium acetate in water containing 0.1%formic acid(V/V)-2 mmol/L ammonium acetate in methanol containing 0.1%formic acid(V/V)was used as the mobile phase.The multiple reaction monitoring mode with electrospray ionization in positive ion mode was used for segmented scanning.The negative organic Lycium barbarum samples were chosen as the blank matrix,and the matrix matching external standard method was used for quantification of these target compounds.Results The 65 kinds of pesticides had good linear relationships within their linear ranges,and the linear correlation coefficients were 0.9962-1.0000 and the limits of detection ranged from 0.5 to 5.0μg/kg,and the limits of quantification ranged from 1.0 to 10.0μg/kg.The recoveries ranged from 65.9%to 117.0%,with relative standard deviations of 2.9%to 13.0%.This method was used to detect 40 Lycium barbarum samples from different sources.A total of 39 pesticides were detected,accounting for 60.0%,including insecticides,fungicides,acaricides,and herbicides.Among them,6 kinds of pesticides such as carbofuran,3-hydroxy carbofuran,omethoate,methamidophos,phorate-sulfoxide,and phorate-sulfone were prohibited and restricted pesticides.The highest detection rate was difenoconazole and acetamiprid,both of which had a detection rate of 97.5%.The highest non-compliance rate was carbofuran,with a non-compliance rate of 25%.Conclusion This method is accurate,sensitive,and fast,and is suitable for detecting residues of 65 kinds of pesticides in Lycium barbarum.It is of great significance to realize the control of Lycium barbarum planting process,daily supervision and quality assurance.