Abstract
Ethiopia is the world's largest producer of teff (Eragrostis tef Zucc). This research was intended to determine the levels of mineral nutrients (metals and nonmetals) and nonessential metals in the grains of teff. Following the optimization of the method, the samples were wet-digested using reagents (5-mL HNO(3) and 1-mL HClO(4)) at a temperature of 230°C for two and a half hours and analyzed using inductively coupled plasma-optical emission spectrometry. Under the optimum procedure, the coefficients of determination (R (2)) ranged between .9980 and .9999. The limits of detection and limits of quantification were in the range of 0.036-14.49 and 0.111-43.93 mg/kg, respectively. The recovery ranged from 80.72% to 107.79%, indicating that the method was accurate. The optimized and validated method was applied to quantify the levels of analytes in the teff samples. The overall mean concentrations of the analytes in the three varieties of teff samples were determined (mg/kg) to be in the order P (3890-4853) > K (3040-3784) > Ca (1906-1959) > Mg (1402-1698) > Fe (128-305) > Mn (64-127.8) > Na (50-136.5) > Zn (19.8-27.3) > B (1.8-21.9) > Cu (4.17-6.9) > Ni (2.6-4.05) > Hg (1.8-4.0) > Pb (0.048-3.7) > Cd (0.012-2.09) > As (0.02-0.24), with a % RSD ranging between 0.017 and 11.1. The results revealed that teff grains are a good source of minerals and contain a significant amount of toxic elements, such as Cd, Hg, Pb, and As.