Optimization of Extraction of Toxic Metals from Medicinal Plants, Malva sylvestris L., and Pistacia lentiscus

Abstract

The goal of the present study was to establish the best procedure for the extraction of metals from medicinal plants. Wet ashing, dry ashing, and microwave digestion methods were applied with different mixtures of nitric and hydrochloric acids using Malva sylvestris L. and Pistacia lentiscus leaves collected from two sites in Algeria. Cadmium, chromium, copper, lead, and zinc were determined by atomic absorption spectrometry. There were significant differences in the metal concentrations extracted by the methods. The highest efficiency from the leaves were obtained using a dry ashing method using 4:1 HNO₃:HCl (v:v), and this approach was considered to be the optimum procedure. However, the wet and microwave digestion methods were suitable for this extraction but with reduced digestion efficiency. The extraction method has a significant influence on the measured metal concentrations, which emphasizes the need to choose the optimum procedure.

Keywords:

• Atomic absorption spectrometry
• Dry ashing
• Medicinal plant
• Microwave digestion
• Toxic heavy metals
• Wet ashing