Semi-automated high-throughput method for residual analysis of 302 pesticides and environmental contaminants in catfish by fast low-pressure GC-MS/MS and UHPLC-MS/MS.

A fast, fit-for-purpose, high-throughput method was developed and validated for the analysis of 302 targeted contaminants in catfish muscle. Targeted contaminants included pesticides and metabolites with US regulatory levels, plus other lipophilic pesticides and environmental contaminants: PAHs, PCBs, PBDEs and other flame retardants. The sample preparation was based on QuEChERS extraction. The extract was split and analyzed by UHPLC-MS/MS for 128 analytes after filtering and by low pressure (LP) GC-MS/MS for 219 analytes after an automated robotic micro-SPE cleanup. The method was validated at four spiking levels (5, 10, 20 and 40 ng/g) with 10 replicates per level, and satisfactory recoveries (70-120%) and RSDs (≤20%) were achieved for 80% of the analytes. The method was further validated with NIST SRMs 1946 and 1947 and applied for the analysis of 22 market fish samples. Six pesticides and one PAH were found in the market fish samples, all below US regulatory levels.