分散固相萃取-气相色谱-三重四极杆质谱分析蔬菜中112种农药残留

评价了分析过程中不同条件下使用分散固相萃取(D-SPE)材料净化对农残分析定量结果可靠性的影响,表明通过条件优化,可明显减小定量误差,并取得满意的回收率。建立了蔬菜中112种农药的多反应监测-气相色谱-串联质谱(GC-MS/MS)检测方法。在pH 5～7范围内,样品经乙腈-甲苯(8:1, v/v)匀浆提取,每5 mL提取液加入0.8 g无水硫酸镁、0.05 g石墨化炭黑(GCB)、0.1 g乙二胺-N-丙基甲硅烷(PSA)、0.05 g C18粉末,分散固相萃取法净化,采用气相色谱-三重串联四极杆质谱(GC-QQQ-MS/MS)在多反应监测模式(MRM)下进行测定,内标法定量。分别对韭菜、黄瓜、紫甘蓝进行3个水平的加标回收试验(20、50、200 μg/kg),其回收率范围为53.1%～138.7%,其中86种农药的3个加标水平的回收率范围均为65.0%～120.0%,方法的相对标准偏差(RSD)小于12%,方法的定量限(LOQ)范围为1.6～13.4 μg/kg。对从市场采集的蔬菜样品进行了测定,检出了三唑磷、甲氰菊酯等农药残留。该方法样品前处理简单快速,灵敏度、准确度和精密度均符合农药多残留检测技术的要求,适用于蔬菜中112种农药残留的快速筛查测定。

Analysis of 112 pesticide residues in vegetables using dispersive-solid phase extraction and gas chromatographytriple quadrupole mass spectrometry

A method was developed and validated for the simultaneous analysis of 112 pesticide residues in vegetables by gas chromatography coupled with triple quadrupole mass spectrometry(GC-QQQ-MS/MS).It is demonstrated that the optimized conditions could provide a more accurate quantitation and lower limit of quantification of the analysis by dispersive-solid phase extraction(D-SPE) cleanup.The samples were extracted with acetonitrile and toluene(8∶1,v/v),and cleaned up by D-SPE.To every 5 mL extraction solution,0.8 g MgSO4、0.05 g graphitized carbon black(GCB),0.1 g ethylenediamine-N-propyl silyl(PSA) and 0.05 g C18 were added.The extracts were analyzed by GC-QQQ-MS/MS using internal standard method.The recoveries of the 112 pesticides at three spiked levels of 20,50 and 200 μg/kg were ranged from 53.1% to 138.7%,and among which those of 86 pesticides were from 65.0% to 120.0%.The relative standard deviations(RSD) were less than 12%.The limits of quantifications(LOQs)(signal/noise at 10) were between 1.6 and 13.4 μg/kg.The vegetable samples collected from the market such as garlic chives,cucumber and purple cabbage were analyzed,and the residues of triazophos and fenpropathrin were detected in some of these samples.The method can be applied to the routine analysis for the determination of the 112 pesticides in vegetable samples.