Spectrophotometric determination of resorcinol by using sodium 1,2-naphthoquinone-4-sulfonate as chromogenic reagent

A novel and simple spectrophotometric method for the direct determination of glucose with 1, 2-naphthoquinone-4-sulfonate reagent is developed in this paper. The method is based on 2-hydroxy-1, 4-naphthoquinone (lawsone) formed from hydroxyl ion and NQS in a buffer solution of pH 13.00 by using glucose as catalyzer. Absorbency is linear with the concentration of glucose in the range of 0.8～80 mg/L at the maximal absorption wavelength of 454 nm. The equation of linear regression is A=0.0165+0.01004C (10-5 mol/L), with a correlation coefficient of 0.9985. The detection limit is 0.7 mg/L (3σ/k) and RSD 1.7%. The method is successfully applied to the determination of glucose in glucose injection.