Question

Find out the role and chemical reactions of the following reagents in the blood glucose level determination by glucose oxidase method. a) Sodium sulphate – Zinc sulphate solution

Answer 1

Benedict’s test to determine the glucose in blood and are based on its property of acting as reducing agent in hot alkaline solution. In hot alkaline condition the aldehyde group of glucose readily reduces cupric ions to cuprous ions, which form cuprous oxide. Sodium sulphate is used in the reagent to decrease the solubility of oxygen in reagent otherwise this oxygen will again reoxide the cuprous oxide.

In somogyi-Nelson method proteins are precipitated by addition of Ba(OH)₂ and ZnSO₄. Protein is removed as zinc proteinate sulfhydryl compounds as zinc salts and the remaining zn and Ba ions as zinc hydroxide and barium sulfate. Before the advent of enzyme assay, this was the reference method for glucose.