Determination of malachite green and crystal violet in fish

A new method of molecularly imprinted solid phase extraction(MISPE) combined with high performance liquid chromatography(HPLC) was developed for detecting malachite green(MG),crystal violet(CV) and their metabolites leucomalachite green(LMG),leucocrystal violet(LCV) in fish.Using MG as template molecule,methacrylic acid as functional monomer,ethylene glycoldimethacrylate as cross-linking agent,molecularly imprinted polymers were synthesized by bulk polymerization and made into extraction column.The significant parameters affecting MISPE were optimized.The fish samples were extracted with acetonitrile by ultrasonic extraction,and cleaned up on MISPE column.Then the residues of MG,CV,LMG and LCV were detected by HPLC.The result showed that linear response data were obtained in the concentration range of 0.01～5 μg/mL for MG,CV and 0.01～10 μg/mL for LMG,LCV with correlation coefficients from 0.9943 to 0.9993.The limits of detection were 0.12 ng/mL for MG,0.02 ng/mL for CV,0.26 ng/mL for LMG and 0.25 ng/mL for LCV.The recovery rate of the fish samples was 97.06%～111.83%,with the relative standard deviations ranging from 1.54%～10.49%.The new established method is simple and fast,accurate and feasible,which can be successfully applied for the determination of MG,CV in fish and their metabolin with low solvent consumption.