Quantification of Residual Organochlorine Pesticides in Medicinal Plant Raw Materials Containing Terpenoids

Abstract

An important indicator of the safety of plant raw materials and herbal medicinal products is the content of residual pesticides. Its determination is particularly difficult in aromatic plants characterised by a diverse composition of terpenoids co-extracting with organochlorine pesticides and forming numerous degradation products that interfere with the analysis.The aim of the study was to develop and validate an analytical procedure for the quantification of organochlorine pesticides in plant raw materials containing terpenoids, compliant with the requirements of the State Pharmacopoeia of the Russian Federation.Materials and methods: the study analysed samples of morphologically different raw materials from 21 plant species containing terpenoids. The analysis was carried out by GLC-MS on a 450-GC gas chromatograph coupled to a 220-MS ion-trap mass spectrometer (Varian, USA) using a FactorFour VF-5ms quartz capillary column (30 m × 0.25 mm).Results: the authors developed the analytical procedure for organochlorine pesticides in medicinal plant raw materials containing terpenoids. Its specificity was confirmed by retention times and mass spectra for all the tested analytes. The recovery of pesticides was studied on model mixtures of a plant raw material and ranged from 70.04 to 99.27%. The authors established the linearity using a calibration curve for internal standard (4,4'-dibromodiphenyl) concentrations from 1.0 to 18.1 µg/mL. The procedure was linear across the entire studied range; the correlation coefficient equalled 0.999. The trueness and precision of the analytical procedure met the acceptance criteria.Conclusions: the analytical procedure has been put into use at the Testing Centre of VILAR. From 2018 to 2020, 63 samples of 21 types of medicinal plant raw materials were analysed and found to be corresponding to the safety requirements for the organochlorine pesticide content. Residual pesticides were detected in the medicinal plant raw materials in few sporadic cases.