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Elemental speciation for bioanalytical applications: HPLC-ICP-MS and CE-ICP-MS
Advances in knowledge of toxicology, clinical chemistry, and nutrition have made the mere determination of an element in a sample insufficient. Both the amount of an element and the forms in which it is present need to be determined. Inductively coupled plasma mass spectrometry (ICP-MS) is a powerful element selective detection method for elemental speciation studies, and was employed as a detection method for high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) separations. An ICP-MS ion pair HPLC method for the separation of selenoamino acid standards was developed. The method was used to identify and quantify selenoamino acids present in water extracts of selenium enriched allium and yeast samples which have been shown to have cancer preventive effects in animal or human studies. Commercially available selenium nutritional supplements were also evaluated. Selenium speciation was shown to vary with level of selenium enrichment and among samples. The method was shown to be compatible with standard ICP-MS operating conditions and electrospray ionization mass spectrometry (ESI-MS). The developed method was also shown to be applicable for sulfur and tellurium speciation studies. The oxidation and reduction of selenoamino acids was investigated by HPLC-ICP-MS. Selenoamino acids were shown to be readily oxidized, and the formation of oxidation products were monitored with time. The presence of oxidized or reduced selenoamino acids in extracts of selenium enriched samples was investigated. The reversibility of the oxidation of some selenoamino acids was demonstrated, and identification of the oxidation products was attempted by ESI-MS. A preliminary evaluation of a CE-ICP-MS interface for metalloprotein speciation was carried out using model proteins and human serum, and its effects on the separation characterized. The adsorption of lead to CE capillaries was investigated. The use of commercially coated and dynamically coated capillaries resulted in reduced lead adsorption.
Bird, Susan Mary, "Elemental speciation for bioanalytical applications: HPLC-ICP-MS and CE-ICP-MS" (1998). Doctoral Dissertations Available from Proquest. AAI9909148.