离子迁移谱法检测圣女果中的敌敌畏和马拉硫磷

Detection of malathion and dichlorovos in cherry tomatoes using a hand-held ion mobility spectrometer

建立了采用便携式离子迁移谱仪(IMS)对敌敌畏和马拉硫磷进行快速检测的分析方法。在大气压条件下,以63Ni作为电离源,干燥洁净的空气作为载气和迁移气,采用负离子模式进行操作,气路采用闭路循环模式。在优化条件下(进样口温度为180℃,迁移管温度为150℃,载气流量和迁移气流量均为0.6L/min)进行检测,敌敌畏和马拉硫磷检测时间小于10s,检测限分别为1ng和5ng。通过在圣女果表面添加敌敌畏和马拉硫磷制成模拟农药残留的实际样品,并用蒸馏丙酮提取圣女果中的残留农药作为样品的前处理方法,对得到的样品进行检测。敌敌畏和马拉硫磷检测结果的RSD分别为8.4%和7.2%,方法适用于快速筛选分析农产品中敌敌畏和马拉硫磷残留的方法。

This paper reports an instrumental analytical approach for rapid detection of malathion and dichlorovos using a hand-held ion mobility spectrometer（IMS）.During the tests,the IMS was operated in the negative mode at ambient pressure using 63Ni as the ionization source and dry,clean air as the carrier gas and the drift gas which circulated in a closed loop system.Tests were first conducted to optimize the operating parameters including the inlet temperature,the drift tube temperature,the drift gas flow rate and the carrier gas flow rate.Under the optimized operating conditions（inlet temperature of 180 ℃,drift tube temperature of 150 ℃,carrier gas flow rate of 0.6 L/min and drift gas flow rate of 0.6 L/min）,the detection limits for dichlorovos and malathion were 1ng and 5ng respectively with the analysis time of less than 10s.Simulated actual samples with pesticide residues were prepared by adding dichlorovos and malathion to the skin of cherry tomatoes.Pretreatment of the sample were adopted by extracting the pesticide residues from the cherry tomatoes with distilled acetone to obtain the sample used for detection under the same operating conditions.The results indicate that the approach is simple,rapid and acceptably reproducible with the relative standard deviations of 8.4% and 7.2% for dichlorovos and malathion respectively,thereby showing great potential as a method for rapid screening and detection of dichlorovos and malathion residues contained in agricultural products.