Since the purified dye yield depends on several parameters
such as solvent types, solid to liquid ratio, time and
temperature, the optimum conditions for purification of
natural dyes are determined. Firstly, one hundred grams of
mango bark powder reflux with the same procedure as the
extraction of crude dyestuff. And then, this extracted solution
is purified with different conditions. The optimum dye
purification conditions are shown in Table II. After extracting
the dye solution, it is filtered and the volume of the solution is
reduced by distillation to get the ⅓ of the dye solution. And
then this solution is kept overnight at room temperature for
precipitation. The precipitate in the ethanol water solution is
obtained with decantation. These active particles, purifie dyes, are dried in the oven at 60°C.