Selenium determination food, vegetable

The foods that are rich in selenium are mainly marine fish, crustaceans and molluscs (such as oysters and prawns), freshwater fish and offal (mainly kidneys). Eggs also have relatively high levels most selenium is contained in the yolk. The content of selenium in mflk, dairy products and meat is lower and is highly dependent on the animal nutrition. Concentrations of selenium in fruits and vegetables, except garhc, are very low (<0.02 mg/kg). Mushrooms contain selenium at the level of 0.03-1.4 mg/kg. The selenium content in foods of plant origin is fundamentally influenced by the selenium content in the soil or fertiliser used and its availability to the plant The concentration of selenium in foods of animal origin is determined by the selenium content in the animal feed. Some pet foods are dehberately fortified with selenium compounds. 

A novel TLC spectrofluorometric method for identification and determination of selenium in different food samples of animal and vegetable origin has been proposed [30]. The procedure involves the digestion of food sample (1 to 5 g) in the presence of cone. HNO3 (5 ml), 70% HCIO4 (10 ml), and FIjO (10 ml) in a 250-ml Kjeldahl flask reduction of Se(VI) into Se(IV) complexation of the isolated selenium with 23-diaminonaphthene (DAN) extraction of the resultant Se—DAN complex with cyclohexane and spectrofluorometric determination followed by confirmation of the presence of Se in the sample by TLC using thin layers of MN-300 cellulose powder. 

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