痕量亚硝酸根的光度测定——基于亚硝酸根对溴酸钾氧化甲酚红的催化作用

Photometric Determination of Trace Amounts of Nitrites Based on Its Catalytic Effect on the Oxidation of Cresol Red by Potassium Bromate

研究了在稀硫酸介质中,亚硝酸根催化溴酸钾氧化甲酚红褪色反应的适宜条件和影响因素,建立了测定痕量亚硝酸根的方法。方法的线性范围为8.0～140μg.L-1,检出限为0.98μg.L-1,方法用于水样中亚硝酸根的测定,RSD为1.9%～3.1%。

In a dil H2SO4 solution, the oxidation of cresol red by KBrO3 was catalyzed by the presence of trace amounts of nitrite, leading to eolorfading of cresol red. Linear relationship between the magnitude of decrease in color intensity at 564 nm （△A=A0-A） and the concentration of nitrite ion was kept in the range of 8. 0- 140. 0 μg · L^-1 , with detection limit of 0. 98 μg·L^-1. In its application to the determination of nitrite in 4 water Samples from different sources, values of RSD＇s （n=6） and recovery found were 1.9%-3.1%.