RESUMO
Trace metal levels in selected medicinal plant leaves from Western Ghats, Karnataka, India were studied A method for the determination of Zinc, Copper, Lead and Cadmium simultaneously in the pH of 4.5 in citrate buffer, and Cobalt and Nickel simultaneously in the pH 9.2 in ammonia buffer medium has been optimized. Electrochemical method, Differential Pulse Anodic Stripping Voltammetry (DPASV) has been used for quantification. The optimized procedure has been successfully applied for the determination of the above-mentioned metal ions in some medicinally important plant leaves from Western Ghats, Karnataka, India. The concentrations of trace metals in the medicinal plant samples were found to be in the ranges: 15.61-20.71 mg g(-1) for copper, 0.056-0.10 mg g(-1) for cadmium, 0.91-1.81 mg g(-1) for lead, 0.42-0.96 mg g(-1) for nickel, 1.21-1.97 mg g(-1) for cobalt and 23.29-32.52 mg g(-1) for zinc. The effect of pH, deposition time and potential has been studied and optimized. The study reveals that all the trace metals are well within the maximum permissible limits, therefore, medicinal plants of this region are very much suitable for medicinal use. The results are compared with the data obtained by atomic absorption spectroscopy.