A rapid screening method for 193 pesticide residues in 3 traditional Chinese medicines containing alkaloids by ultrahigh-performance liquid chromatography coupled to quadrupole-orbitrap high resolution mass spectrometry

A method for the fast screening and detection of 193 pesticide residues in 3 traditional Chinese medicines containing alkaloids was established based on ultrahigh-performance liquid chromatography coupled to quadrupole-orbitrap high resolution mass spectrometry (UPLC-Q-Orbitrap HRMS). The samples were extracted by QuEChERS method, cleaned up by dispersed solid phase extraction (d-SPE) with cation exchange adsorbents, and separated by Agilent Poroshell 120 EC-C₁₈ column (3.0 mm × 150 mm, 2.7 μm) with aqueous solution and methanol solution containing 0.1% formic acid and 5 mmol/L ammonium formate as mobile phase. Mass spectrometry adopted the full scan/data dependent acquisition mode (Full MS/ddMS²). External standard method was used for quantitative analysis. The results showed that 193 pesticides had good linear relationships within the corresponding concentration ranges, and the correlation coefficients (r) were all above 0.99, and the limits of quantification (LOQs) were 10-100 μg/kg. At three different spiking levels of 10, 50 and 100 μg/kg, the average recoveries of 193 pesticides in Rhizoma Corydalis, Rhizoma Coptidis and Cortex Phellodendri were in the range of 58%-120%, 68%-124% and 73%-122%, respectively, and the relative standard deviations (RSDs) were within 20% (n=6). The sample preparation of the established method is simple and rapid. Using the UPLC-Q-Orbitrap HRMS, through the quantitative and qualitative analysis of precursor ions and the qualitative confirmation of fragments ions and retention time, the screening accuracy of pesticide residues in traditional Chinese medicines containing alkaloids was significantly improved. It can be used for the rapid screening and daily risk monitoring of pesticide residues in the three traditional Chinese medicines containing alkaloids.