亚硝酸根-中性红-8-羟基喹啉偶联反应光度法测定亚硝酸根

Determination of Nitrite by Spectrophotometry on the Coupled Reaction of Nitrite-Neutral Red-8-hydroxyquinoline

关键词:  亚硝酸根  中性红  8-羟基喹啉  分光光度法

Key words:  nitrite  neutral red  8-hydroxyquinoline  spectrophotometry

摘要:

研究中性红与亚硝酸根在盐酸介质中重氮化,然后在氨性溶液中与8-羟基喹啉偶联成黄褐色产物的反应。偶联产物的最大吸收波长在560nm,据此建立了一个简单、快捷、选择性较好的测定亚硝酸根的可见分光光度法。该法的摩尔吸光系数ε₅₆₀=1.32×10⁴L·mol^-1·cm^-1,测定的线性范围为0~880 μg/L。用于水样、食品、蔬菜样品中亚硝酸根的测定,结果满意。

Abstract:

A new spectrophotometric method for the determination of nitrite was developed. In acidic solution, nitrite was first diazotized with neutral red, followed by coupling with 8 hydroxyquinoline to produce an azo-compound. This azo-compound has a maximum absorption at 560 nm. Beer's law is obeyed for nitrite in the range of 0 to 880 μg/L. The molar absorptivity is 1.32×10⁴L·mol^-1·cm^-1.This method was used to determine trace nitrite in water of lake, flour and potato samples with satisfactory results.