亚硝酸根－对氨基苯磺酸－H酸偶联反应体系光度法测定亚硝酸根的研究

Spectrophotometric Determination ofNitrite by Coupling to H-acid

本文根据亚硝酸根与对氨基苯磺酸、Ｈ酸在酸性介质中进行的重氮偶联反应，提出了一个测定痕量亚硝酸根的分光光度新体系。最大吸收波长为５２０ｎｍ，摩尔吸光系数为３．１×１０￣４Ｌ／ｍｏｌ·ｃｍ，亚硝酸根浓度在０～１．２μｇ／ｍＬ范围内符合比耳定律．用于水样中亚硝酸根的分析，测定结果与经典的α－萘胺法一致。

A new spectrophotometric method forthe determination of nitrite is proposed.Inacidic solution,nitrite is first derivatized bydiazotization with p-aminobenzene sulfonicacid ,followed by coupling to H-acid to pro-duce an azo compound.This azo compoundhas a maximum absorption at 520nm. Beer’slaw is obeyed for in the range of 0～1.2μg/mL。The molar absorptivity is 3.1×10￣4L/(mol · cm ).The method is simple,rapid,sensitive and selective. It has beenused for the determination of trace nitrite inwater with satisfactory results.