Determination of Selenium in Medical Samples, Staple Food and Dietary Supplements with the Bruker S2 PICOFOX

Selenium is essential for many aspects of human health and, thus, the object of intensive medical research. This demands the use of analytical techniques capable of analysing selenium at low concentrations with high accuracy in widespread matrices and sometimes smallest sample amounts. In connection with the increasing importance of selenium, there is a need for rapid and simple on-site (or near-to-site) selenium analysis in food basics like wheat at processing and production sites, as well as for the analysis of this element in dietary supplements.

Common analytical techniques like electro thermal atomic absorption spectroscopy (ETAAS) and inductively-coupled plasma mass spectrometry (ICP-MS) are capable of analysing selenium in medical samples with detection limits in the range from 0.02 to 0.7 μg/l. Since in many cases less complicated and expensive analytical techniques are required, therefore Bruker have tested their total reflection X-ray fluorescence (TXRF) spectrometer S2 PICOFOX extensively regarding its suitability for selenium analysis in different medical, food basics and dietary supplement samples, applying simplest sample preparation techniques.

Bruker has published an article in Spectrochimica Acta that summarizes the findings of the described tests: H. Stosnach, Analytical determination of selenium in medical samples, staple food and dietary supplements by means of total reflection X-ray fluorescence spectroscopy, Spectrochim. Acta B (2010). The results obtained indicate that the accurate analysis of selenium in all sample types is possible with the S2 PICOFOX. The detection limits of TXRF are in the range from 7 to 12 μg/l for medical samples and 0.1 to 0.2 mg/kg for food basics and dietary supplements. Although this sensitivity is lower compared to established techniques, it is more than sufficient for the physiological concentrations of selenium in the investigated samples. Also it offers the advantage that sample preparation is reduced to a minimum and only minute amounts of sample are required. Also the S2 PICOFOX is capable of simultaneous multi-element analysis, which makes the method even more convenient.