Determination of malachite green and metabolites residues in fish by ultra-high performance liquid chromatography-tandem mass spectrometry

This paper optimized the method of GB/T 19857-2005,and established a method for determination of malachite green(MG) and leucomalachite green(LMG) residues in fish through ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS).The samples were extracted with acetonitrile,cleaned up with neutral alumina column,and separated by Zorbax Eclipse Plus-C₁₈ chromatographic column.The acetonitrile-5 mmol/L ammonium acetate buffer solution was used as mobile phase.Then aims compound were detected by UHPLC-MS/MS with ESI positive ion mode and multiple reactions monitoring(MRM) mode,and quantified by using isotope internal standards.The results showed that both MG,LMG contents had good linear relationship within the range of 0.5~20.0 ng/mL,and the correlation coefficient was 0.999.The detection limits was 0.05 μg/kg.The average recoveries ranged from 81.3% to 103.3% at the spiked levels of 0.5,1.0,and 2.0 μg/kg in Oreochromis mossambicus,Ctenopharyngodon idellus,Scophthalmus maximus,Siniperca chuatsi,Trachinotus ovatus,and Ophiocephalus argus Cantor.The relative standard deviation of determination results was less than 10%(n=6).These results suggested that the method was accurate,rapid and saving reagents,which would be suitable for the detection of MG and LMG residues in fish.