Determination of mercury and selenium in consumed food items, in Libya using instrumental and radiochemical NAA

Instrumental and radiochemical neutron activation analysis (INAA and RNAA, respectively) were used to analyze several consumed food items in Libya for the detection of low level concentrations of mercury and selenium. Selenium was determined using both short- and long-term irradiation, while mercury was determined in the long-term irradiation mode. At RNAA, after wet-ashing of samples in a microwave digestion unit, mercury was extracted with Ni(DDC)(3)/CHCl3, and selenium was precipitated in elemental form with ascorbic acid. For quality control, NIST reference materials were analyzed using the same procedures as for the food samples. The results of the analytical modes used were compared.