反相流动注射催化光度法测定亚硝酸根

RP-FIA CATALYTIC PHOTOMETRIC DETERMINATION OF TRACE AMOUNTS OF NITRITES

采用反相流动注射技术与催化光度法相结合 ,研究了亚硝酸根在盐酸介质中催化溴酸钾氧化维多利亚蓝的灵敏褪色反应 ,用自制的微机化流动注射分析仪能准确控制时间 ,优化了试验条件 ,建立了测定痕量亚硝酸根的反相流动注射催化光度新方法。分析速度 36次·h- 1,克服了催化反应时间难以控制引起的方法精密度 ,准确度不高的弱点。亚硝酸根在 0 .0 0～ 2 .0 0mg·L- 1范围内 ,回归方程斜率为 0 .2 6 2。

It was observed that the color-fading of victoria blue due to its oxidation by potassium bromate in a dilute hydrochloric acid medium was remarkably catalyzed by the presence of trace amounts of nitrites. Based on this phenomenon, a sensitive photometric method for the determination of trace amounts of nitrite was proposed. To achieve a more efficient time control for the catalytic reaction and an automatic operation, a reverse-phase FIA instrumentation was designed to be used for the above mentioned catalytic photometric reaction. Under the optimum conditions established, a sampling rate of 36 times per hour was attained with relatively high accuracy and precision. Linearity was held in the range 0.00～2.00mg of NO - 2 per 1L of solution. The linear regression equation was found as follows: A=0.875-0.262C(r=0.998). The proposed method has been satisfactorily used in the determination of traces of nitrite ions in waste water from power plant and in well water.