新催化动力学光度法测定痕量亚硝酸根

PHOTOMETRIC DETERMINATION OF TRACE AMOUNTS OF NITRITES BY ITS CATALYTIC EFFECT THE OXIDATION OF AMIDO BLACK 10B BY POTASSIUM BROMATE

在磷酸介质中,痕量亚硝酸根对溴酸钾氧化酰胺黑10B的催化褪色作用,建立了催化动力学光度法测定痕量亚硝酸根的新方法。并探讨了动力学反应条件,方法的线性范围为0.05～1.2μg/10ml,检出限为4.88×10-9·ml-1,用于地面水及雨水中亚硝酸根的测定,结果满意。

In a dilute phosphoric acid medium (c(H3PO4)=0. 05mol·L-1), the oxidation of amido black 10B by KBrO3 is catalyzed by traces of nitrite (NOr ) ion, leading to color-fading of the dyestuff. The decrease in absorbance (AA) at 618nm is found to be in linear relationship with the concentration of NO2- in the range of 0. 05-1. 2μg per 10ml of solution. The detection limit of this method is 4. 88×10-9g·ml-1. Based on these facts, a catalytic-kinetic photometric method for the determination of traces of NO2- is established and has been applied satisfactorily to the analysis of ground water and raining water samples. The kinetic condition of the oxidation reaction is also studied.