Speciation of metals and metalloids in biomolecules by hyphenated techniques

This paper introduces briefly the analytical methods recently published in the literature on the speciation of arsenic, selenium and cadmium in biological samples using hyphenated techniques, HPLC-ICP-MS, HPLC-ES-MS/MS, and CE-ES-MS/MS. The coupling SEC-ICP-MS is the most popular technique for the first screening of unknown sample in view of the presence of macro molecular species of element. But due to its insufficient resolution, complementary chromatographic separations have to be carried out in order to guarantee the purity of the signal. CZE-ICP-MS is a powerful tool in trace metal speciation. In case standards and reference materials are not available, ES-MS/MS is the best technique in the characterization of metal complexes. During analysis care should be taken to avoid contamination of the sample and break-up of the original metal-protein bond during the separation process. Due to lack of standards and reference materials, the application of hyphenated technique has been looking for new species rather than determining a known compound. The difficult problems are whether a signal produced by a detector belongs to a particular compound and the identification of this compound.