气相色谱-串联质谱法测定黄秋葵中107种农药残留量
GC-MS/MS Determination of Residual Amounts of 107 Pesticides in Okra
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摘要: 经捣碎的黄秋葵样品(10.0 g)中加入乙酸-乙腈(1+99)溶液10 mL和氯化钠5 g,匀浆提取2 min,离心5 min;取上清液2.00 mL,与无水硫酸镁150 mg,N-丙基乙二胺(PSA) 25 mg和C18 25 mg涡旋振荡1 min作净化处理后离心3 min。取其上清液1.00 mL,加入100 mg·L-1环氧七氯溶液4 μL作为内标,按程序升温进样,用Rxi-5Sil MS石英毛细管色谱柱分离。MS/MS分析中采用电子轰击离子源(EI)和多反应监测(MRM)模式。在选定的条件下测定了107种农药的残留量,结果表明:107种农药的线性范围均在0.040~0.80 mg·L-1之间,各组分的检出限(3S/N)在0.5~8 μg·kg-1之间。在3个浓度水平上作加标回收试验,计算得回收率在65.1%~109%之间,测定值的相对标准偏差(n=6)在2.0%~9.6%之间。Abstract: The pounded okra sample (10.0 g) was extracted with 10 mL of a mixture of CH3COOH-CH3CN (1+99) and 5 g of NaCl by homogenization for 2 min and centrifugation for 5 min. 2.00 mL of the supernatant was taken and mixed with 150 mg of anhydrous MgSO4, and 25 mg each of PSA and C18 for purification by swirling for 1 min and centrifuging for 3 min. 1.00 mL of the supernatant was taken and 4 μL of 100 mg·L-1 heptachlorepoxide solution was added to it as internal standard. This mixed solution was used for GC-MS/MS determination of 107 pesticides as residues in okra. Temperature-programmed sample introduction and Rxi-5Sil MS quartz capillary chromatographic column were used in GC separation. EI and MRM mode were adopted in MS/MS analysis. As shown by the results, linearities were found for 107 pesticides in the same range of 0.040-0.80 mg·L-1, with detection limits (3S/N) ranged from 0.5 to 8 μg·kg-1. Test for recovery was made by standard addition method at 3 concentration levels, giving values of recovery in the range of 65.1%-109%, and values of RSD (n=6) found wre in the range of 2.0%-9.6%.