Determination of selenium in Libyan food items using pseudocyclic instrumental neutron activation analysis

Cyclic and pseudocyclic instrumental neutron activation analysis (INAA) has been used to determine the Se content of 40 Libyan food items. The selected samples include different varieties of local and imported foods such as wheat and barley products (bran and flours), rice, bread, almond, peanuts, vegetables as bean and peas, tea, coffee, sugar, and commonly used spices such as red and black paper, curry, cumin, mixture of spices, thyme, coriander, and fenugreek. Both conventional and anticoincidence gamma-ray spectrometry techniques have been employed. Pseudocyclic INAA in conjunction with anticoincidence counting has been found to provide the most reliable results. The precision of the method has been significantly improved by recycling the samples up to three times. The accuracy has been evaluated by analyzing a number of certified reference materials of varied Se levels. The detection limit has been found to vary between 26 and 90 ppb Se depending on the sample composition. The range of daily dietary intake has been calculated as 13-44 microg of Se per day.