凝胶渗透色谱-气相色谱-离子阱质谱法测定桔梗原药和当归提取物中101种农药残留

建立了凝胶渗透色谱（GPC）-气相色谱-离子阱质谱同时检测桔梗原药和当归提取物中101种农药残留的分析方法。方法采用乙腈超声辅助提取桔梗原药和当归提取物，浓缩提取液至近干后用乙酸乙酯-环己烷（1∶1， v/v）复溶，采用凝胶渗透色谱法（选取40 cm长、内径20 mm的凝胶渗透色谱柱）对样品进行净化，弃去前段含脂类、色素等杂质的流出液，收集17~30 min洗脱液并旋转蒸发浓缩至近干，甲苯1 mL定容上机。选用DB-5MS毛细管色谱柱分离待测物，通过离子阱质谱实现对101种农药残留的高效检测。方法通过优化前处理条件和离子阱二级质谱参数，有效降低了复杂中药基质对待测化合物的干扰，最大限度提高了样品中农药的定量准确性和回收率，101种农药3水平添加的平均回收率为58.3%~108.9%，每个添加水平10次独立重复测定的相对标准偏差为0.4%~16.5%，检出限（LOD）范围为0.2~40.0 μg/kg，可满足当前韩国、日本、欧洲规定的最大残留限量（maximum residue limits， MRLs）要求。方法具有操作简单快速、灵敏度高、重复性好等特点，凝胶渗透色谱技术的应用克服了固相萃取小柱净化容量不足的弊端，离子阱技术的应用可以进一步排除共流出基体杂质的干扰，提高定量和定性的准确性，检测效果优于常用的气相色谱-质谱法，是对中药中同时分析多种农药残留检测方法的有益补充。

Determination of 101 pesticide residues in Platycodonis radix and extracts of Angelica sinensis by gel permeation chromatography-gas chromatography-ion trap mass spectrometry

With the growing global popularity of traditional medicine and natural drugs， especially in Southeast Asia， the quality of traditional Chinese medicines （TCMs） has attracted the attention of regulators. China’s major TCM export destinations， such as South Korea， Japan， and Europe， have formulated strict maximum residue limits （MRLs） of pesticides in TCMs. Therefore， a sensitive and high-throughput method for the simultaneous determination of 101 pesticide residues in Platycodonis radix and extracts of Angelica sinensis was established， involving gel permeation chromatography （GPC） coupled with gas chromatography-ion trap mass spectrometry （GC-ITMS）. In this method， the samples were first ground into fine powder and extracted twice with 20 mL acetonitrile in an ultrasonic cleaner for 30 min. After centrifugation for 10 min at 6000 r/min， the supernatants were combined and dried at 40 ℃ using a rotary vacuum evaporator. The residue was re-dissolved in 2 mL ethyl acetate-cyclohexane （1∶1， v/v） and purified by gel permeation chromatography using a 40 cm×20 mm column. The eluent collecting time was optimized as 17-30 min to ensure both the recovery of target compounds and the removal of interferences such as pigments and lipids from the target compounds. The eluent was then dried and re-dissolved with 1 mL toluene for analysis. The 101 pesticide residues were separated using the DB-5MS capillary column and analyzed by ion trap mass spectrometry. The pretreatment conditions and ion trap mass spectrometry parameters were optimized to effectively reduce the interference of complex TCM matrices and greatly improve the quantitative accuracy of the analysis and recovery of the target pesticides. Three spiked levels of 101 pesticides were tested. The average recovery range was 58.3%-108.9% and the relative standard deviations （RSDs） at the three spiked levels （n=10） ranged from 0.4% to 16.5%. The limits of detection （LODs， S/N=3） of the 101 pesticide compounds ranged from 0.2 to 40.0 μg/kg， while the limits of quantification （LOQs， S/N=10） ranged from 0.6 to 120.0 μg/kg， which met the maximum residue limits of China’s main TCM export countries and organizations. This rapid analysis method was easy to operate and high throughput， with strong sensitivity and good repeatability. The employment of gel permeation chromatography overcame the drawback of inadequate cleanup of the solid phase extraction column during TCM analysis. The application of ion trap technology further eliminated the interference of matrix impurities and increased the accuracy of the quantitative and qualitative analyses. This method fills the knowledge gap in multiple pesticide residue determination in TCMs using gas chromatography-ion trap mass spectrometry and is a useful and beneficial alternative to current analytical methods of TCMs.