Development of a simultaneous pesticide analysis method for herbal medicines using a modified extraction procedure and ultrahigh-performance liquid chromatography tandem mass spectrometry

Abstract

Owing to complex matrix interference and low analyte concentrations, pesticide residues in herbal medicines pose considerable health and environmental risks. In this study, a modified QuEChERS protocol combined with ultra-high-performance liquid chromatography–tandem mass spectrometry was developed for the simultaneous determination of 239 pesticides in six widely used herbal medicines. Extraction was performed using MeCN/EtOAc (7:3, v/v) acidified with 0.1 % formic acid to enhance the recovery of both acidic and neutral compounds, followed by dispersive SPE cleanup using 150 mg of MgSO₄ and 25 mg of C₁₈ to reduce matrix effects. Chromatographic separation was performed on a C₁₈ column using a gradient of water and methanol (both containing 5 mM ammonium formate and 0.1 % formic acid), and sensitive MRM detection was achieved using electrospray ionization with positive/negative polarity switching. Method validation was conducted using Paeoniae Radix, Cnidii Rhizoma, Rehmanniae Radix, Corni Fructus, Artemisiae Argyi Folium, and Carthami Flos, following the European Commission SANTE/2020/12,830 guidance. For over 90 % of pesticides, calibration curves exhibited R² > 0.99, and recoveries ranged from 70 to 120 % with RSD < 20 %. Thus, the proposed method is rapid, facile, reliable, and effective for analyzing pesticide residues in diverse herbal medicines.