Abstract
Arsenic has been proved to be a toxic and cancerogenic element. Besides, the biological importance is dependent on the species in which arsenic appears. Therefore, the elucidation of the mechanisms governing the essentiality and toxicity of trace elements in living organisms is critically dependent up the possibility of the characterization and determination of physical or chemical forms of these elements involved in life processes. The purpose of this study is to develop a separation system allowing the identification of arsenic species in serum samples. The analytical system was based on a two dimensional liquid chromatography system consisting of size-exclusion chromatography (SEC) and reversed-phase liquid chromatography (RPLC) with on-line detection of arsenic by inductively coupled plasma mass spectrometry (ICP-MS) and then the arsenic-containing fraction was analysed by ES-MS. In the first-dimension separation, SEC was found to be particularly well suited for protein separation and it provides easily interpretable qualitative information: the molecular weight of the arsenic specie is about 1500 Da. After SEC separation, RPLC was emplyed for second dimensional separation of the fraction containing arsenic. The effects of spectral interferences for the determination of arsenic species in serum samples with the proposed analytical system were investigated, and the results indicated that the on-line ICP-MS determination can be completely free from interferences with the prior column separation step.