Analytical methods - Se
The concentration of Selenium in most foods is low; therefore, accurate determination requires a sensitive analytical method and freedom from contamination. Inductively coupled plasma mass spectrometry (ICP-MS) EuroFIR Method Indicator MI1209 is the most reliable method preceded by wet digestion MI1018 or pressure digestion (Link).
Method feature is described in EN 14627:2005- Foodstuffs - Determination of trace elements - Determination of total arsenic and selenium by hydride generation atomic absorption spectrometry (HGAAS) after pressure digestion. Other methods are available: AOAC (AOAC 986.15) and CODEX. Southgate and Greenfield Book.