Automated QuEChERS for the determination of 482 pesticide residues in Radix codonopsis by GC-Q-TOF/MS and LC-Q-TOF/MS?

Analytical MethodsANAL METHODS-UK Pub Date: 2021-11-01 DOI: 10.1039/D1AY01616D

Abstract

A rapid procedure for the determination of 482 pesticide residues in Chinese Materia Medica by GC-Q-TOF/MS and LC-Q-TOF/MS (379 pesticides for LC, 327 pesticides for GC, and 226 pesticides for both) was developed. Radix codonopsis was chosen as the matrix for verification, and a comparative study on the QuEChERS sample preparation was carried out, between a fully automated workstation and manual operation, in terms of limits of quantitation, recovery rate and RSD at 3 spiked levels of 10 μg kg?1, 20 μg kg?1 and 100 μg kg?1. In the linear range of each pesticide in a concentration range of 5–100 μg L?1, the linear correlation coefficients R2 of 85% of the pesticides for GC and 88% for LC were equal to or greater than 0.990. Taking recovery 70–120% and RSD ≤ 20% as the satisfactory standard, the automated workstation performed better at 10 μg kg?1 and 20 μg kg?1 than manual operation, and the numbers of satisfactory pesticides of GC & LC were 401 and 418 for the automated approach, and 378 and 400 for manual, while the two approaches were almost even at 100 μg kg?1, 421 vs. 424. Besides, the automated workstation presented lower RSD (more pesticides ≤10%) and better recovery quality (more pesticides within 90–110%). Following the method verification, 50 Radix codonopsis samples purchased from local markets were prepared with the automated workstation and analyzed by GC and LC-Q-TOF/MS. 18 pesticides were detected in 38 samples, one of which was a highly toxic pesticide. The automated QuEChERS workstation can handle 40 samples in one cycle within 6 hours, and realize whole-process automation covering from samples after “weighing” to “injection into vials”. The batch-to-batch, day-to-day, and lab-to-lab consistency and 24 × 7 workability of the automated solution have demonstrated a promising and ideal replacement for manual operation in sample preparation.

Graphical abstract: Automated QuEChERS for the determination of 482 pesticide residues in Radix codonopsis by GC-Q-TOF/MS and LC-Q-TOF/MS
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