固相萃取毛细管气相色谱法测定中草药中13种有机氯农药的残留量

Determination of Organochlorine Pesticide Residues in Nine Herbs by Solid-Phase Extraction and Capillary Gas Chromatography

建立了中草药中有机氯类农药残留量的固相萃取毛细管气相色谱(SPECGC)分析方法。对丹参、黄芩、射干、白芍、白芷、天南星、牛蒡子、知母、桔梗共9种中草药中六六六的4种异构体、滴滴涕的4种异构体、七氯、艾氏剂、环氧七氯、狄氏剂、异狄氏剂共13种有机氯农药的残留量进行了测定。以丙酮正己烷混合物作提取剂,采用超声波提取样品,然后用Florisil固相萃取小柱快速净化提取物。采用SPB5弹性石英毛细管气相色谱柱分离样品,电化学检测器进行检测。13种农药的峰面积与其质量浓度均有良好的线性关系,相关系数均大于0.998。最小检测量为0.064～0.61μg/L;样品的加标回收率为87.3%～102.3%(相对标准偏差为1.3%～6.8%)。该法简便快速、灵敏准确,具有广泛的应用前景。

The solid-phase extraction and capillary gas chromatography was introduced for determining 13 organochlorine pesticide residues including α-benzene hexachloride (BHC), β-BHC, γ-BHC, δ-BHC, p,p′-dichloro-diphenyl-dichloroethylene (pp′-DDE), p,p′-dichloro-diphenyl-dichloroethane (pp′-DDD), o,p′-dichloro-diphenyl-trichloroethane (op′-DDT), pp′-DDT, heptachlor (HEPT), aldrin, heptachlor epoxide (HCE), dieldrin and endrin in Scutellaria baicalensis, Salvia miltiorrhiza, Belamcanda chinensis, Paeoniae lactiflora, Angelica dahurica, Arisaema erubescens, Fructus arctii, Anemarrhena asphodeloides and Platycodon grandiflorum.The organochlorine pesticides were extracted from herbs with mixed solvents of acetone and n-hexane by ultrasonic and cleaned up by Florisil solid-phase extraction column. Then, the extract was separated by capillary column (30 m×0.25 mm i.d.×0.25 μm ) and detected by electrochemical detector. The carrier gas was N 2(99.999%) with the flow rate of 1.4 mL/min. The split ratio was 1∶2.2. The injector temperature was 220 ℃ and the detector temperature was 330 ℃. The column temperature was increased by the rate of 20 ℃/min from 100 ℃ to 190 ℃ (hold for 1.0 min), then to 235 ℃ by the rate of 4 ℃/min and hold for 7 min at 235 ℃. The good linearities were obtained for 13 organochlorine pesticides. The detection limits were between 0.064-0.61 μg/L. The average recoveries were between 87.3%-102.3% and relative standard deviations of 1.3%-6.8%. The method is effective, fast and accurate.