Spectrophotometric Determination of Hydroquinone with Sodium 1,2-Nnaphthoquinone-4-sulfonate as Chromogenic Reagent

A novel and simple spectrophotometric method for determination of hydroquinone with 1,2-naphthoquinone-4-sulfonate reagent was developed.The method was based on 2-hydroxy-1,4-naphthoquinone(lawsone) formed from hydroxyl ion and NQS in a buffer solution of pH=13.00 with hydroquinone as a catalyst.Absorbency was linearly proportional to the concentration of hydroquinone in a range of 1.3×10-7~1.32×10-5 g/mL at the maximal absorption wavelength of 454 nm.The equation of linear regression was A=0.025 61+0.073 28c(1×105 mol/L),with a correlation coefficient of 0.995 5.The detection limit was 9×10-8 g/mL(3σ/k),and the recovery was in a range of 96.5%~103%.The method has been successfully applied to the determination of hydroquinone in water.