Development and validation of a QuEChERS extraction-UPLC-MS/MS method for the simultaneous determination of chloramphenicol drugs in Laminaria japonica and Porphyra yezoensis

The analysis of the content of chloramphenicol (CAPs) in Laminaria japonica and Porphyra yezoensis samples is crucial for quality control of seaweed products. In this study, the analytical method using QuEChERS combined with Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) was established to separate and detect residues of chloramphenicol, thiamphenicol, and florfenicol in Laminaria japonica and Porphyra yezoensis. The extraction solvent used was acetonitrile, and a 1:1 mixture of graphitized carbon black (GCB) and C18 was employed as the purifying agent. Electrospray ionization (ESI) in negative ion mode with multiple reaction monitoring (MRM) was employed, coupled with the isotope internal standard quantification method. The results demonstrated good linearity within a range of 0.0005–0.050 μg/mL for chloramphenicol, thiamphenicol, and florfenicol with correlation coefficient (r) of 0.999. The method detection limit was 0.4 μg/kg, while the quantitation limit was 1.0 μg/kg. Furthermore, during validation experiments where concentrations ranging from 1.0 μg/kg to 10.0 μg/kg were added to samples, recovery rates for chloramphenicol ranged from 87.4 % to 103.4 %, with relative standard deviations (RSDs) between 2.1 % and 5 %. This developed method was applied to test twenty batches of samples in which one batch of Laminaria japonica was found to contain a chloramphenicol concentration of approximately 2.0 μg/kg. The developed method, which uses simple and cost-effective sample pretreatment techniques, is suitable for qualitative determination. It satisfies the experimental requirements in terms of accuracy and sensitivity when monitoring large quantities of marine algae products containing CAPs.