二甲酚橙催化光度法测定亚硝酸根的研究

Catalytic spectrophotometic determination of nitrite with xylenol orange

基于硫酸介质中亚硝酸根催化溴酸钾氧化二甲酚橙的褪色反应 ,建立了测定痕量亚硝酸根的新方法 ,并探讨了动力学条件 ,测定了反应的表观速率常数( k=1 .32× 1 0 -3 S-1)和表观活化能 ( Ea=35 .0 2 k J/mol)。方法的测定范围为 0～ 0 .1 8μg/m L,检出限为 1 .1 ng/m L。

A new catalytic spectrophotometic method for determination of trace nitrite was developed. The method is based on the catalytic effect of NO - 2 on oxidation of xylenol orange by potassium bromate in H 2SO 4 medium. The kinetic condition was studied, and the apparent activation energy and apparent rate constant were determined. The linear range is 0～0.18 μg/mL for nitrite with detection limit of 1.1 ng/mL. The method was applied to direct determination of nitrite in water and brake fluid samples.