RESUMO
With the growing global popularity of traditional medicine and natural drugsï¼ especially in Southeast Asiaï¼ the quality of traditional Chinese medicines ï¼TCMsï¼ has attracted the attention of regulators. China's major TCM export destinationsï¼ such as South Koreaï¼ Japanï¼ and Europeï¼ have formulated strict maximum residue limits ï¼MRLsï¼ of pesticides in TCMs. Thereforeï¼ a sensitive and high-throughput method for the simultaneous determination of 101 pesticide residues in Platycodonis radix and extracts of Angelica sinensis was establishedï¼ involving gel permeation chromatography ï¼GPCï¼ coupled with gas chromatography-ion trap mass spectrometry ï¼GC-ITMSï¼. In this methodï¼ 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/minï¼ the supernatants were combined and dried at 40 â using a rotary vacuum evaporator. The residue was re-dissolved in 2 mL ethyl acetate-cyclohexane ï¼1â¶1ï¼ v/vï¼ 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 ï¼RSDsï¼ at the three spiked levels ï¼n=10ï¼ ranged from 0.4% to 16.5%. The limits of detection ï¼LODsï¼ S/N=3ï¼ of the 101 pesticide compounds ranged from 0.2 to 40.0 µg/kgï¼ while the limits of quantification ï¼LOQsï¼ S/N=10ï¼ ranged from 0.6 to 120.0 µg/kgï¼ 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 throughputï¼ 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.