Of the sample approximately 0.5 g was weighed and placed in a 100-ml Kjeldhal flask. Concentrated sulfuric acid 1-3 ml. was added and heated for 20 min, first gently and then more vigorously.Then, 8 ml of 30% hydrogen peroxide was added dropwise to decolorize the solution. The mixturewas boiled vigorously to remove excess hydrogen peroxide and allowed to cool. Finally the sample was diluted to 10 ml with distilled water.