Determination of Levels of Essential and Toxic Heavy Metals in Lentil (Lens culinaris Medik) by Flame Atomic Absorption Spectroscopy

Abstract

The concentrations of trace essential metals (Co, Cu, Fe, Mn, Ni and Zn) and toxic heavy metals (Cd and Pb) in lentil samples collected from Dejen (East Gojjam), Boset (East Shewa) and Molale (North Shewa), Ethiopia, were determined by flame atomic absorption spectrometry. A wet digestion procedure, using mixtures of HNO₃, HClO₄ and H₂O₂ was developed for the decomposition of powdered lentil samples. The accuracy of the method was checked by the standard addition method. The contents of heavy metals in lentil samples were in the range of 0.009-0.013 for Cd, 0.285-0.360 for Co, 0.226-0.282 for Cu, 9.17-11.91 for Fe, 6.7-8.2 for Mn, 0.120-0.244 for Ni, 0.142-0.176 for lead and 8.62-10.03 for Zn, all in mg/100 g. The results were compared with values reported in the literature.