Determination of selected major and trace metals in lemongrass (Cymbopogon citratus) by microwave plasma-atomic emission spectrometry

Abstract

Cymbopogon citratus is very important and of great interest due to its commercially valuable essential oils, its common use in food and beverage industries as well as in traditional folk medicine. The objective of the present study was to determine the levels of selected major (K, Mg, Ca) and trace (Mn, Fe, Cu, Zn, and Pb) metals in lemongrass (Cymbopogon citratus) samples collected from Addis Ababa, Ankober, Finote Selam (Gojjam), and Wondogenet by microwave plasma-atomic emission spectrometry. The optimized wet acid digestion method for the analysis of lemongrass was found efficient for all the metals and it was evaluated through the recovery test and good percentage recovery of 86.9 to 106% was obtained for all the metals identified. The metals K, Ca, Mg, Fe, Mn, Cu, Zn and Pb were with a concentration of 743.8-1020, 123.1-129.3, 23.9-36.3, 10.35-22.3, 10.0-12.7, 1.48-2.53, 0.59-1.07, 0.13-0.20 mg/kg, respectively. The results of the Pearson correlation showed that there was a weak and strong positive correlation between the concentrations of the metals analyzed. Statistical analysis by using one-way anova indicated that there were significant differences in the mean concentrations of all the metals (except Ca and Mn) across each sampling points. The results also showed that Cymbopogon citratus are beneficial sources of essential metals. The levels of the metals in the analyzed samples were within the who maximum permissible limits and thus safe for human consumption.