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    QuEChERS样品制备系统联合气相色谱-串联质谱法测定松林土壤中6种杀虫剂的残留量

    Determination of Residues of 6 Insecticides by Gas Chromagraphy-Tandem Mass Spectrometry Combined with QuEChERS Sample Preparation System

    • 摘要: 随机采集松林土壤样品,风干、除杂、粉碎、过筛,分取10 g置于QuEChERS样品制备系统整合管外管中,加入一个氧化锆瓷珠包(20粒氧化锆瓷珠)、20 mL乙腈和一个QuEChERS提取包(内置5.0 g无水硫酸镁和1.0 g乙酸钠),再将内置1.0 g无水硫酸镁、500 mg N-丙基乙二胺(PSA)、500 mg C18和15 mg石墨化碳黑(GCB)的一个QuEChERS净化包置于整合管内管中,将整合管加载至QuEChERS样品制备系统,振荡10 min,离心5 min,重复上述振荡和离心过程一次,即完成样品的提取和净化。收集净化液,冷冻离心5 min,上清液于50℃氮吹至近干,残渣用1 mL丙酮复溶,过0.22 μm滤膜,滤液供气相色谱-串联质谱法(GC-MS/MS)分析。6种杀虫剂(氯氟氰虫酰胺、氰戊菊酯、戊菊酯、治线磷、丰索磷和杀螟松)用Rxi-5Sil MS色谱柱在程序升温条件下分离,用电子轰击离子(EI)源电离,用多反应监测(MRM)模式检测,外标法定量。结果显示:6种杀虫剂的质量浓度在0.01~3.00 mg·L-1内与峰面积呈线性关系,检出限(3S/N)为0.012~0.021 μg·kg-1;按照标准加入法进行回收试验,回收率为86.2%~102%,测定值的相对标准偏差(n=5)为1.6%~4.2%;方法用于5份实际样品的分析,检出了丰索磷、杀螟松、氰戊菊酯和氯氟氰虫酰胺,检出量为14.22~125.35 μg·kg-1

       

      Abstract: Pine forest soil samples were randomly collected, dried by air, removed impurities, ground and sieved. An aliquot (10 g) of the sample together with a zirconia ceramic bead bag (20 zirconia ceramic beads), 20 mL of acetonitrile and a QuEChERS extraction bag (containing 5.0 g of anhydrous magnesium sulfate and 1.0 g of sodium acetate) was taken and placed into the outer tube of the QuEChERS sample preparation system integration tube. A QuEChERS purification bag containing 1.0 g of anhydrous magnesium sulfate, 500 mg of PSA, 500 mg of C18 and 15 mg of GCB was placed into the inner tube of the integration tube, and the integration tube was loaded into the QuEChERS sample preparation system. The mixture was shaken for 10 min and centrifuged for 5 min, and the above shaking and centrifugation processes were repeated once, to complete the extraction and purification of the sample. The purified solution was collected, and freeze centrifuged for 5 min. The supernatant was blown to near dryness at 50℃ by nitrogen, and the residue was dissolved by 1 mL of acetone. The resulting solution was passed through a 0.22 μm filter membrane, and the filtrate was analyzed by GC-MS/MS. Six insecticides (cyhalodiamide, fenvalerate, valerate, curmidophos, fensulfothion and fenitrothion) were separated by Rxi-5Sil MS column under temperature programmed conditions, ionized by EI source, detected by MRM mode, and quantified by external standard method. It was shown that linear relationships between values of the mass concentration and the peak area of the 6 insecticides were kept in the range of 0.01-3.00 mg·L-1, with detection limits (3S/N) in the range of 0.012-0.021 μg·kg-1. Test for recovery was made according to standard addition method, giving recoveries in the range of 86.2%-102%, and RSDs (n=5) of the determined values ranged from 1.6% to 4.2%. The proposed method was applied to the analysis of 5 actual samples, and fensulfothion, fenitrothion, fenvalerate and cyhalodiamide were detected, with detection amounts in the range of 14.22-125.35 μg·kg-1.

       

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