Analysis of selenized yeast for selenium speciation by size-exclusion chromatography and capillary zone electrophoresis with inductively coupled plasma mass spectrometric detection (SEC-CZE-ICP-MS)

• Published in: Journal of analytical atomic spectrometry 2002-01, Vol.17 (1), p.15-20
• Main Authors: Mounicou, Sandra, McSheehy, Shona, Szpunar, Joanna, Potin-Gautier, Martine, Lobinski, Ryszard
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemical Sciences; Electrophoresis; Inductively coupled plasma; Molecular weight; Selenium; Size exclusion chromatography; Yeast
• ISSN: 0267-9477; 1364-5544
• DOI: 10.1039/b107943n

A two-dimensional separation approach based on size-exclusion chromatography (SEC) followed by capillary zone electrophoresis (CZE) is proposed for the mapping of seleno-compounds in aqueous extracts of selenized yeast. The coupling of CZE with ICP-MS via a self-aspirating total consumption micronebulizer was optimized for the separation of Se species. Selenate, selenite, selenocystine, selenomethionine and selenoethionine could be baseline separated at pH 10.5 using a 10 mM phosphate buffer containing 0.8 mM cetyltriammonium bromide. Detection limits were 7-18 ng mL super(-1) for a 20 nL injection. The CZE-ICP-MS analysis of a yeast extract demonstrated the presence of many Se species, which all migrated less rapidly than any of the standards. The following difficulties occurred during the CZE-ICP-MS analysis of the SEC fractions of the extract: the recovery of the high-molecular Se-species from the electrophoretic capillary, the presence of a large number of compounds in the medium-molecular weight fraction and the presence of a single intense peak for the low-molecular weight fraction. Proteolysis of the high- and medium-molecular weight fractions dramatically improved the recovery of Se species from the capillary, resulting in several peaks in the CZE-ICP-MS electropherograms.