甲基橙反应体系新用途——光度法测定亚硝酸根

New Use of Yellow Methyl Reaction System——Spectra- photometric Determination of Nitrite

基于亚硝酸根重氮化反应后生成甲基橙 ,用分光光度法进行测定。与传统甲基橙合成反应不同的是 ,此反应可在常温下短时间内快速完成。有色物质的摩尔吸光系数为 4.38× 1 0 4L/( mol·cm) ,方法的相对标准偏差为 0 .2 1 % ,方法回收率 1 0 0 .5 % ,亚硝酸氮的浓度在 0 .0 1 6～ 0 .1 6μg/m L与吸光度有良好的线性关系。

The method for spectrophotometric determination of nitrite based on the formation of an azo dye is reported. In a low pH condition, nitrite is first diazotized with p aminobenzene then the diazotate is coupled with N,N dimethylbenzene amine to form a yellow compound methyl orange, which is later acidulated and the color is changed into red. The molar absorbance coefficient is 4.38×10 4L/(mol·cm), the relative standard deviation of the method is 0.21% and the recovery is 100.5%. The linearity for nitrite nitrogen is ranged 0.016~0.16 μg/mL.