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Die Bodenkultur - Journal for Land Management, Food and Environment
M. Stadlober, M. Sager and K.J. Irgolic:
Identification and Quantification of Selenium Compounds in Sodium Selenite Supplemented Feeds by HPLC-ICP-MS
An anion exchange chromatographic system was coupled to an HP 4500 inductively coupled plasma mass spectrometer (ICP-MS) for the identification and quantification of selenium compounds in animal feeds. Separation of selenite, selenare, selenocystine, and selenomethionine was achieved by high performance liquid chromatography (HPLC) on a Hamilton PRP-X100 column using a 10 mM citrate buffer (pH 5), 2 % methanol as mobile phase and a flow rate of 1.5 ml min-1. Four baseline separated chromatographic peaks were obtained within 6 minutes. Using aqueous extracts of the feeds, selenite and sometimes a poor signal of respective selenate were identified. However, only 15 to 50 % of the total concentration of selenium was found. This suggests that part of the selenite was converted to less soluble forms in the feeds. Different extraction techniques and extraction solvents, including enzymatic hydrolysis were tested with respect to a possible enhancement of the extractable amount of selenium. Keywords: High Performance Liquid Chromatography, Anion Exchange Chromatography, Inductively Coupled Plasma Mass Spectrometry, Selenium, Feeds.