Analysis Method Study On Mercury And Lead Species In Food By HPLC-ICP-MS

Mercury (Hg) and Lead (Pb) are two typical trace elements with highly toxicity. Their toxicity not only depends on the total content levels, but also associated with the existence speciation. Developing a simple and effective quantitative analysis method of Hg and Pb 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 seven Hg and Pb based on HPLC-ICP-MS was established with C18 column as stationary phase and metal chelating agent as additive of mobile phase. Ultimately the optimal chromatographic conditions was confirmed,0.10%(w/v) L-cysteine,1 mg L-1 EDTA,0.025 mol L-1 sodium acetate,10% methanol, pH 4.6, flow rate of 1.0 mL min-1, the detection condition of ICP-MS and the pretreatment procedure of different samples were evaluated in this research.. 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 Hg and Pb species achieved to 0.13-0.16 μgL-1[Hg2+],0.10-0.11 μgL-1[MeHg+],0.16-0.19 μg L-1 [EtHg+],0.19-0.22μg L-1 [PhHg+]; 0.11-0.14 μg L-1 [Pb2+],0.09-0.12 μg L-1 [Me3Pb+],0.21-0.25 μg L-1 [Et3Pb+], respectively. Under the optimized conditions, good linearity on Hg and Pb species in the range of 1.0-100 μg L-1 was achieved with R2> 0.9990. Furthermore, this present method was evaluated by analyzing the Hg and Pb species in several typical food samples (rice, wheat, pork, chicken, codfish, squid, shrimp and water). The content of Hg and Pb species in these samples are lower than the value in GB/T 2762-2005. And the results also signified great difference between the total Hg and Pb concentrations and the chemical speciation of Hg and Pb in different foods. The recoveries were obtained in the range of 76.3±2.2%-102.8 ±3.5%.