QuEChERS-气相色谱-串联质谱法测定天麻药材中70种农药及其代谢物的残留量

Determination of Residues of 70 Pesticides and Their Metabolites in Gastrodiae Rhizoma by Gas Chromatography-Tandem Mass Spectrometry with QuEChERS

提出了Qu ECh ERS提取、净化,气相色谱-串联质谱法测定天麻药材中70种农药及其代谢物残留量的方法。取3.00 g过20目(850μm)筛的粉末样品置于50 m L聚丙烯具塞离心管中,加入1%(体积分数)乙酸溶液15 m L,涡旋混匀,浸泡30 min。加入15 m L乙腈,振荡5 min,加入6 g无水硫酸镁和1.5 g乙酸钠,立即摇散,振荡3 min,于冰浴中冷却10 min,以转速4 000 r·min^(-1)离心5 min。取上清液9 m L置于Qu ECh ERS分散固相萃取管(无水硫酸镁900 mg、N-丙基乙二铵300 mg、十八烷基硅烷键合硅胶300 mg、硅胶300 mg和石墨化碳黑90 mg)内,涡旋并振荡5 min,以转速4 000 r·min^(-1)离心5 min,取上清液5 m L于40℃氮吹至0.4 m L,用乙腈稀释至1.0 m L,过0.22μm尼龙滤膜,滤液按照仪器工作条件测定。70种农药及其代谢物在HP-5MS色谱柱上经升温程序分离,以电子轰击离子源电离,多反应监测模式检测,基质匹配法定量。结果表明:70种农药及其代谢物的质量浓度均在5~150μg·L^(-1)内和峰面积呈线性关系,测定下限均为0.01 mg·kg^(-1)。按照标准加入法进行回收试验,回收率为87.9%~111%,测定值的日内相对标准偏差(n=5)均小于10%,日间相对标准偏差(n=10)均小于20%。方法用于18批天麻样品的分析,均未检出70种农药及其代谢物。

The QuEChERS was used for extraction and purification,and gas chromatography-tandem mass spectrometry was proposed to determine residues of 70 pesticides and their metabolites in Gastrodiae Rhizoma.3.00 g of powder sample,which sieved through 20 mesh(850μm)sieve,was taken and placed in a 50 mL-polypropylene stoppered centrifuge tube.15 mL of 1%(volume fraction)acetic acid solution was added,and the mixture was vortexed well,and soaked for 30 min.15 mL of acetonitrile was added,and the mixture was shaken for 5 min.6 g of anhydrous magnesium sulfate and 1.5 g of sodium acetate were added,and the mixture was shaken immediately,shaken for 3 min,cooled in an ice bath for 10 min,and centrifuged at a rotational speed of 4000 r·min^(−1) for 5 min.9 mL of the supernatant was taken and placed in a QuEChERS dispersion solid-phase extraction tube(including 900 mg of anhydrous magnesium sulphate,300 mg of N-propylethylenediamine,300 mg of octadecylsilane bonded silica gel,300 mg of silica gel,90 mg of graphitized carbon black).The mixture was vortexed and shaken for 5 min,and centrifuged at a rotational speed of 4000 r·min^(−1) for 5 min.5 mL of the supernatant was taken,concentrated to 0.4 mL by nitrogen at 40℃,and diluted to 1.0 mL with acetonitrile,which was passed through a 0.22μm nylon filter membrane.The filtrate was determined according to the operating conditions of the instrument.70 pesticides and their metabolites were separated using the HP-5MS chromatographic column under programmed heating conditions,ionized by electron impact ion source,and detected using the multiple reaction monitoring mode,with matrix matching method for quantification.As shown by the results,linear relationships between values of the mass concentration and the peak area of 70 pesticides and their metabolites were kept in the range of 5-150μg·L^(−1),with lower limits of determination of 0.01 mg·kg^(−1).Test for recovery was made according to the standard addition method,giving recoveries in the range of 87.9%-111%,with the intra-day RSDs(n=5)of the determined values less than 10%and the inter-day RSDs(n=10)of the determined values less than 20%.This method was used for the analysis of 18 batches of Gastrodiae Rhizoma samples,and 70 pesticides and their metabolites were not detected.