Abstract: An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of the residues of prometryn and its metabolites in aquatic products was developed using a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method for sample pretreatment. Homogenized samples were extracted with acetonitrile and purified by the combined use of enhanced matrix removal of lipids (EMR-Lipid) and Cleanert LipoNo. The detection was carried out in the positive ion mode with selected reaction monitoring (SRM) and the internal standard method was selected for quantification. Under the optimal conditions, the calibration curves for prometryn and its four metabolites were linear with correlation coefficient (R2) above 0.992 in the concentration range of 1–500 ng/mL. The limits of detection (LODs) and limits of quantitation (LOQs) for all analytes were as low as 0.20 and 0.50 μg/kg, respectively. For spiked grass carp, crayfish and Chinese mitten crab, good accuracy and precision were observed, with average recoveries and relative standard deviations (RSDs) ranging from 74.4% to 113.7% and 3.17% to 11.47%, respectively. After correction by the internal standard method, the matrix effects of the five compounds in different aquatic products were not significant. The developed method allows the identification and quantitative analysis of the residues of prometryn and its metabolites in aquatic products. Additionally, the applicability of this method was validated by detecting positive samples of crayfish bathed with prometryn.

Key words: ultra-high performance liquid chromatography-tandem mass spectrometry; aquatic products; prometryn; metabolites; quick, easy, cheap, effective, rugged and safe