ASSESSING THE METHOD OF DETERMINING THE QUANTITY OF METALS IN DRIED STEVIA LEAVES BY ATOMIC ABSORPTION SPECTROPHOTOMETER

Abstract

This study was constructed to develop and validate the recovery, sensitivity and repeatability of the Atomic Absorption Spectrophotometera (AAS) method in the measuring the quatity of metals in dried stevia leaves.The developed method was linear over the concentration ranging  0 - 4 mg/L (Cu, Fe) and 0 – 1 mg/L (Zn, Mn). The correlation coefficient (r) obtained for all metals is higher than 0.99. Limit of detection (LOD) of Cu, Fe, Zn and Mn found was 0,083 ppm, 0.016 ppm, 0.004 ppm and 0,007 ppm respectively. The recovery and repeatability in this method were for determining enough these heavy metals in dried stevia leaves sample. The developed method has been successfully used for determination of Cu, Fe, Zn and Mn levels in dried stevia leaves in Vietnam.