The contents were evaporated to reduce the volume to 3–5 ml.
The completion of digestion was confirmed by the formation of
colorless liquid. After cooling, 20 ml of de-ionized water was added
and the solution was filtered through Whatman filter paper 1. The
aliquots of this solution were used for determination of mineral
elements. Individual standard stock solutions (1 mg/L) for each
mineral element were prepared for quantification.