Chapter 26: Speciation of Organic and Inorganic Selenium in Food and the Environment

Selenium is an essential element for humans. Selenium integrates proteins with antioxidant activity in the organism. Selenium enters the body mainly through the diet. Selenium presence in food depends on it is cycle in the environment. It is absorbed by plants from soil, and it is biomagnified through the food chain. Selenium distribution in the environment depends on its chemical specie. In addition selenium bioavailability in food is higher for organic species, like seleno-amino acids, rather than inorganic forms. Determination of specific seleno-species requires speciation analysis. Speciation analysis involves the coupling of a separation technique to a selenium detector. The separation techniques involved in speciation analysis are chromatographic procedures. The chromatographic mode employed depends on the selenium specie to be separated. Inductively coupled plasma mass spectrometry (ICP MS) is the preferred detector according to its sensibility and easy coupling. In recent years novel seleno-species have been described, like selenium-nanoparticles and selenized polysaccharides. Identification of novel seleno-species requires more selective and sensitive detectors like electrospray mass spectrometry (ESI MS).