Three sections of the Stevia rebaudiana plant were used for the experiment. The section consists of leaves, stems
and flowers. The raw material was purchased from Malacca, Malaysia. The materials were dried using oven
equipment at 60oC for 24 hours to remove the moisture contains in leaves, stems and flowers. The dried materials
were grinded to produce a powder and were measured the particle size (160μm) using a vibrator sieve shaker to give
a good surface area for the extraction process. For the heavy metals determination, leaves, stems, and flowers of
Stevia rebaudiana plants of each weighed approximately 0.5 grams into a Teflon digestion vessel, to which was
added exactly 7 ml high purity concentrated 65% of nitric acid (HNO3) and 1 ml high purity concentrated 30% of
hydrogen peroxide (H2O2). The vessels were then capped and fitted into rotor segments and inserted into the
microwave digestion system. The samples were radiated for 20 min. Upon cooling, the vessels were uncapped and
solutions transferred into 50 ml volumetric flasks.