[Rapid determination of chlorfenapyr and its metabolites in plasma by high performance liquid chromatography-tandem mass spectrometry].

Objective: To establish a rapid method for the determination of chlorfenapyr and its metabolite tralopyril in human plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) . Methods: In January 2025, after human plasma samples were pretreated by acetonitrile protein precipitation combined with liquid-liquid extraction, separation was performed using a Kinetex EVO C18 chromatographic column. Methanol-water was used as the mobile phase with isocratic elution at 75% B. Electrospray ionization in negative ion mode (ESI(-)) and multiple reaction monitoring (MRM) mode were adopted for detection, and the matrix-matched external standard method was applied for quantification. A comprehensive methodological validation was completed in accordance with the Guidelines for the Validation of Quantitative Analytical Methods for Biological Samples. Results: Chlorfenapyr in human plasma showed good linearity in the concentration range of 2-400 μg/L, with a correlation coefficient (r) of 0.99954. The average spiked recoveries ranged from 98.3%-112.8%, with both intra-batch and inter-batch relative standard deviations (RSD) below 10%. The limit of detection (LOD) was 0.67 μg/L, and the lower limit of quantification (LOQ) was 2.0 μg/L. For tralopyril, good linearity was observed in the range of 0.1-20.0 μg/L, with a correlation coefficient (r) of 0.99979. The average spiked recoveries ranged from 98.4%-113.0%, with both intra-batch and inter-batch RSD below 10%. The LOD was 0.003 μg/L, and the LOQ was 0.010 μg/L. Conclusion: This method features simple pretreatment, rapid analysis, high sensitivity, and satisfactory precision and accuracy. It meets the requirements for rapid quantitative detection of chlorfenapyr and tralopyril in plasma of clinically poisoned patients.