Determination of malachite green,crystal violet and its metabolites residues in aquaculture water and sediment using ultra-high performance liquid chromatography tandem mass spectrometry

An ultra high performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) method was developed for the simultaneous determination of malachite green(MG),crystal violet(CV),and its metabolites(leucomalachite green(LMG) and leucocrystal violet(LCV)) residues in aquaculture water and sediment.Sediment samples were freeze-dried under vacuum and extracted with acetonitrile and dichloromethane,followed by cleanup using MCX solid phase extraction cartridge; the freeze-dried residues of aquaculture water were reconstructed in 50% acetonitrile-water solution(containing 0.1% formic acid) and then centrifuged and filtered before UPLC-MS/MS analysis.Chromatography separation was accomplished on a Waters BEH C18 column under gradient elution condition.Qualitative and quantitative analysis of target analytes was carried out in multiple reaction monitor(MRM) positive ionization mode.Internal standard calibration curves were obtained in the concentration range of 0.50 ~ 50 μg/L with good correlation coefficients(r 0.99).The limits of detection(LODs) and the limits of quantification(LOQs) were in the range of 10 ~ 25 ng/L(S/N = 3)and 25 ~ 50 ng/L(S/N = 10) for aquaculture water,while 0.020 ~ 0.025 μg/kg and 0.04 ~ 0.05 μg/kg for sedment respectively.The mean recoveries were between 85.2% and 105.6% with relative standard deviation(RSD) less than 12%.The proposed method was applied to the determination of prohibited drugs in real aquaculture water and sediment samples,which obtained satisfactory results.