催化反应-示波极谱测定痕量亚硝酸根——NO_2^--MR-BrO_3^-催化体系

Catalytic Reaction-Oscillopolarographic Method for the Determination of Trace Amounts of Nitrite——Studies on the Catalytic System of NO2--BrO3--Methyl Red

基于在0.016mol/L H_2SO_4中及加热条件下,NO_2^-对BrO_3^-氧化甲基红有强烈的催化作用,籍自来水冷却中止反应,以NaOH作示波极谱测量指示组分甲基红(E_p=-0.56V,vs.SCE)的支持电解质,建立了NO_2^-的第一个催化反应-示波极谱分析法。该法检出限为0.035ng/mL,测定范围为0.1～50ng/mL。

The present paper covers a novel and highly sensitive catalytic method for the determination of nitrite as low as 0. 1 ng/mL, It is based on the fact that the nitrite ion catalyses the slow redox reaction between methyl red and BrO3- in 0. 016 mol/L H2SO4 at 100℃. Cooling by tap water was chosen to quench the reaction. And oscillopolarography was used as detection technique for methyl red in NaOH medium which exhibits a sensitive oscillopolarographic wave at -0. 56 V vs. SCE. Nitrite in water samples was analysed by this method with excellent results.