Analysis Method Study On Arsenic And Selenium Species In Food By Hplc-Icp-Ms

Arsenic (As) and Selenium (Se) are two typical trace elements with double function. Their nutrition and toxicity not only depends on the total content levels, but also associated with the existence speciation. Due to unstable chemical speciation, some complicated sample pretreatment and analytical procedures would lead to content loss and speciation alternation of As and Se. Developing a simple and effective quantitative analysis method of As and Se total content determination and chemical speciation has become an important challenging topic. The combination of HPLC with high separation efficiency and ICP-MS with high insensitivity is the most widely used and effective analytical method in currently element speciation analysis.In this work, a speciation analysis method for ten As and Se based on HPLC-ICP-MS was established with C18column as stationary phase and imidazoles room temperature ionic liquids (RTILs) as ion pair reagent. This experiment focused on the optimization of experimental parameters including the type and concentration of RTILs, the gradient elution program, the pH of mobile phase, the flow rate and column temperature of HPLC, the detection condition of ICP-MS and the pretreatment procedure of different samples. The detection limit (LOD), accuracy and precision of the developed method were also evaluated in this research.From the obtained results, the LOD for different As and Se species achieved to0.32-0.41μg L-1[As(Ⅲ)],0.38-0.45μg L-1[As(V)],0.60-0.69μg L-1[AsB],0.76-0.78μg L-1[AsC],0.80-0.86μg L-1[DMA],0.81-0.89μg L-1[MMA],0.91-0.98μg L-1[SeCys2],1.20-1.29μgL-1[Se(IV)],1.08-1.13μgL-1[SeMet],1.49-1.57μg L-1[Se(VI)], respectively. Under the optimized conditions, good linearity on As and Se species in the range of2.5-10000μg L-1was achieved with R2>0.9990. Furthermore, this present method was evaluated by analyzing the As and Se species in several typical food, samples (pork, chicken, rice, wheat, codfish, shrimp, beer, white sprit and milk). The recoveries were obtained in the range of70.6±2.5%-125.5±3.5%. And the results also signified great difference between the total As and Se concentrations and the chemical speciation of As and Se in different foods.