An analytical study of bioaccumulation and the binding forms of mercury in rat body using thermolysis coupled with atomic absorption spectrometry Original Research Article

This study concerns with the development and application of a mercury analyzer system capable of quantitative analysis and binding forms of trace mercury in different body tissues of rats after oral intake of cinnabar and HgCl2. The analyzer consists of a temperature programmed thermolysis unit for sample decomposition and mercury release, coupled downstream to an atomic absorption spectrometry for mercury detection. No sample digestion was needed and this greatly simplifies the analytical procedure and minimizes potential sources of contamination. The precision of the method is in general better than 1.4%; the detection limit (3σ) is 6.3 ng/g; the recovery based on the analysis of standard reference materials ranges from 93.5 to 107%. The performance of the method has been compared with inductively coupled plasma–mass spectrometry (ICP–MS) technique and excellent agreements were observed between the two methods. The method has been applied to the investigation of the distribution and binding forms of mercury in rats, which had been fed orally with cinnabar and HgCl2. The results obtained show that mercury is mainly accumulated in the tissues of liver and kidney, meanwhile, the mercury levels in different tissues change with the feeding time, dosage and the chemical form of mercury compounds. In addition to total mercury measurements, the mercury thermal release profiles obtained from temperature programmed thermolysis provides mercury binding forms information, and preliminary data suggest the presence of protein/polypeptide-bound Hg compounds in kidney samples of rats.