Analysis
Sample: Standard solution , Sample solution, and blank.
Add 2.0 mL of freshly prepared Alkaline Cupric tartaric to test tubes containing 2.0 mL of the Standard solution,2.0 mL of the Sample solution,or 2.0 mL of the Blank . After 10 min ,Add 1.0 mL of Dilute Folin Ciocalteu reagent to each test tube ,and mix immediately and vigorously .After 30 min , measure the absorbance of the standart solution and Sample and sample solution against the blank.
Acceptance criteria: NMT 6.0% on the dried basis; the absorbance of the sample solution is NMT the absorbance of the Standard solution.