当溶液中同时存在Ni2+和Sn4+离子时，如何测定其中Sn4+的含量，而使Ni2+对测定没有影响？

本文研究了在盐酸介质中微量亚硝酸根与煌焦油蓝发生的重氮化反应，建立了测量微量亚硝酸根的新方法。方法的线性范围为0.5～12 μg NO－2／25 mL，检出限为0.5 μg NO－2／25 mL。方法已用于水中微量亚硝酸根的测定。并对机理进行了初步讨论。
主题词：煌焦油蓝， 亚硝酸根， 分光光度法

Study on Spectrophotometric Determination of Trace Nitrite with Brilliant Cresol Blue

Chunzhi DONG and Fangyong MING
Department of Chemistry,Huaibei Coal Teacher's College,235000 Huaibei

Abstract A new spectrophotometric method for the determination of trace nitrite was studied.The method is based on the diazo-reaction of brilliant cresol blue with nitrite.The linear range for the determination is 0.5—12 μg NO－2／25 mL.The detection limit is 0.5 μg NO－2/25 mL.The method has been used for the determination of trace nitrite in water.The mechanism of the reaction was discussed.
Keywords Brilliant cresol blue, Nitrite, Spectrophotometry

亚硝酸根与人体健康密切相关，亚硝酸根广泛存在于水体、食品及环境中，与芳胺或芳甲酰胺反应后能生成致癌物质亚硝胺，因而是水质、食品和环境检测的重要指标之一。目前，光度法测定亚硝酸根的方法有催化法〔1〕，重氮化偶联法〔2〕，亚硝化法〔3〕等，但利用煌焦油蓝与亚硝酸根发生的重氮化反应测定微量