Fast analysis of malachite green, leucomalachite green, crystal violet and leucocrystal violet in fish tissue based on a modified QuEChERS procedure

Abstract

Triphenylmethane dyes malachite green (MG) and crystal violet (CV) have been used as antimicrobial, antiparasitic and antiseptic agents in aquaculture. However, MG and CV, as well as their metabolites leucomalachite green (LMG) and leucocrystal violet (LCV) are potential mutagens and carcinogens. Thus, the efficient determination of dye residues is of great concern. Considering the complexity of the aquatic products, the sample pretreatment is significant for decreasing matrix interference and improving detection sensitivity. In this study, a simple and rapid QuEChERS procedure was developed and combined with HPLC analysis for the simultaneous determination of the four dyes in fish tissue. An XCharge C18 column was applied in HPLC analysis to achieve good peak shape and selectivity. The pretreatment method involved the extraction of dyes from fish tissue and further clean-up with dispersive solid phase extraction (d-SPE) material. The extraction volume, extraction time as well as d-SPE materials were systematically optimized. The results indicated that reversedphase/strong anion exchange (C18SAX) adsorbent in the d-SPE procedure could effectively improve the recovery compared with conventional C18 or C18 incorporated with primary secondary amine (PSA) material. Under optimized conditions, good linearity was achieved in the concentration range of 0.5-100 mg/L with R2 greater than 0.998. The recoveries were 73%-91% and the precisions were 0.66%-5.41%. The results demonstrated the feasibility and efficiency of QuEChERS procedure incorporated with HPLC for dye monitoring.