Capillary electrophoresis coupled to inductively coupled plasma mass spectrometry (CE/ICP-MS) and to electrospray ionization mass spectrometry (CE/ESI-MS): An approach for maximum species information in speciation of selenium

On-line hyphenations consisting of a separation and a detection step are on e of the most efficient techniques for identification and characterization of metal containing species. The high resolution power of capillary electro phoresis (CE) is used for the separation of three selenium species, whereas either electrospray ionization mass spectrometry (ESI-MS) or inductively c oupled plasma mass spectrometry (ICP-MS) are taken for molecule or element specific detection. This work gives an overview about the possibilities and limitations, when u sing the two hyphenated systems for speciation investigations. In order to show the power of the two complementary techniques, a CZE method using 5% a cetic acid as background electrolyte was applied to the separation of selen omethionine (SeM), selenocystine (SeC) and selenocystamine (SeCM). Depending on the species and the element, the detection limits of the CE/IC P-MS hyphenated system are up to 10(2) to 10(3) times better than that for the CE/ESI-MS system.