Optimization Of The Detection Methods Of Malachite Green And Dietary Exposure Assessment

Malachite green(MG) and crystal violet(CV), belong to triphenylmethane compounds, had been used worldwide as fungicide and antiparasitic to prevent and treat fish diseases in aquaculture. However, they had been prohibited to be usded in fishery in many countries due to their mutagenic, teratogenic and carcinogenic natures. Ministry of Agriculture of China had completely banned the use of MG in food animal production in May2002. Nevertheless, MG is illegal used because of its excellent antibacterial with low cost. So the rapid, sensitive and accurate determination methods for the banned veterinary like malachite green are very necessary.In this article, the determination method for such banned veterinary in aquatics as MG and CV was optimized. And some aquatic fish products were detected for monitoring the misuse of MG and CV using the established method. Furthermore, the dietary exposure risk of MG was estimited.1. A method combining molecularly imprinted solid-phase extraction (MISPE) and high performance liquid chromatography-linear ion trap mass spectrometry was developed for the simultaneous determination of MG, CV and brilliant green (BG) and their metabolites in aquatic products was optimized. The isocratic elution condition during LC seperation was optimized to gradient elution. The double peak of MG was studied. ESI positive ion scan mode was used with selected reaction monitoring (SRM, MS2) for qutification and consecutive reaction monitoring (CRM, MS3) for confirmation. Compared with the traditional MCX cartridge, the MISPE showed priority in the aspect of high selectivity and sensitivity. And so better purification was acquired, which lead to minor ion suppression in the process of mass spectromic analysis. Decision limits (CCa, α=1%) and detection capability (CCβ, β=5%) of MG, CV and BG in aquatic samples were0.14～0.46μg/kg and0.22～0.70μg/kg, respectively. The method was successfully applied to detect MG, CV, BG and their metabolites in aquatic products.2. The validated methodology was applied to89acuatic samples which were purchased from local supermarket. The results showed that57.3%of the samples were contaminated by MG with the maximum concentration of1459.67μg/kg, and5.6%of the samples contained CV with the maximum concentration of3.07μg/kg, and BG was not detected in all the samples.3. According to the results, the dietary exposure risk of MG was estimated. The margin of exposure (MOE) of MG of average-exposure groups, high-exposure groups and extra high-exposure groups were500000,13158and432, respectively. The results demonstrated that in average-exposure groups and high-exposure groups, the health risk was acceptable, however the health risk of the extra high-exposure groups was high enough to give priority management.