Speciation of Selenium in a Commercial Dietary Supplement by Liquid Chromatography Coupled with Inductively Coupled Plasma–Mass Spectrometry (ICP-MS)

Abstract

Size exclusion and anion-exchange chromatographies coupled with inductively coupled plasma-mass spectrometry (ICP-MS) were used for the speciation of selenium (Se) in a dietary supplement. A sequential extraction method resulted in 85% recovery of Se and 78% of the Se extracted could be identified. The results obtained show that selenomethionine and its oxide are the predominant compounds, while selenite and selenomethylcysteine are present at low concentrations. Methane seleninic acid, probably arising from the oxidation of selenomethylcysteine, accounted for 22% of total Se. High-molecular-weight compounds, probably proteins, were detected in sodium dodecyl sulfate (SDS) and driselase extracts by size exclusion chromatography.

Modeling of Mechanisms of Selenium Bioactivity Using Density Functional Theory

“…Seleninic acids (RSeO 2 H) release Zn 2+ from zinc-finger proteins (21,22), regulate the activity of tumor-suppressor protein p53 (71) and inhibit thioredoxin reductase (5,72). This over-oxidized form of selenium is found in commercial selenium supplements (73), as an oxidative product of selenoamino acids (74), and as a intermediate in a proposed GPx-like mechanism of ebselen (75). The X-ray structures of GPx and the semisynthetic selenosubtilisin show that the active site SeCys has been air-oxidized to the seleninic acid form (76,77).…”

Speciation of Selenium in Biological Samples by Ion Chromatography With Inductively Coupled Plasma Mass Spectrometry

“…[14] Thus, ultrasonic probe proteolysis has been offered as an Selenium in Biological Samples 1155 85 [45] efficient alternative to reduce extraction time for catalyzing the breakdown of Se containing proteins (peptide bonds) into selenoamino acids. For example, the release of selenomethionine from selenized yeast using a ultrasonic probe was completed in only 30 seconds.…”

“…[43] Another separation scheme combined size exclusion and anion-exchange chromatographies coupled with ICP-MS for Se speciation in dietary supplement. [45] Some unidentified high molecular weight Se compounds (22%) in the samples were observed from a sequential extraction steps and separated by SEC. [45] Affinity chromatography combined with SEC-ICP-MS has been used to separate three major Se-containing proteins (albumin, glutathione peroxidase, and selenoprotein P) from human plasma.…”

The Applicability of Plasma‐Based Techniques to Biological Monitoring

“…Rats were fed either a normal diet, a low-protein diet, or a famine diet. The methods applied were GC-MS and ICP-MS [276]. The suitability of the sea urchin as a sentinel organism for the assessment of the macrozoobenthos health state in biomonitoring programs was studied.…”