Standard solution was freshly prepared each day with 8 mL of stock solution made up to 50 mL with solution of 0.3 M TCA and treated with 1 g of activated carbon during 30 min and filtered.
Standard solution was freshly prepared each day with8 mL of stock solution made up to 50 mL with solution of 0.3M TCA and treated with 1 g of activated carbon during 30min and filtered.