双波长双指示剂催化动力学光度法测定痕量亚硝酸根

在磷酸介质中,利用亚硝酸根催化溴酸钾氧化亮绿和甲基橙褪色的指示反应,建立催化光度法测定痕量亚硝酸根的新方法．该反应的最大吸收峰在500nm和640nm处,线性范围1-11μg/25mL,其检出限为2．82×10^-10mg／L,相对标准偏差0．05％．本方法灵敏度高,体系稳定,具有较好的选择性,用于自来水中痕量亚硝酸根的测定,结果较为满意．

Dual- Wavelength and Dual- Indicator Catalytic Kinetic Spectrophotometry for Determination of Trace Nitrite

A catalytic kinetic spectrophotometric method for determination of trace nitrite was proposed in the paper. The method was based on the catalytic effect of nitrite ion on the oxidation fading reaction of methyl orange and bright green with potassium bromate as oxidant in phosphoric acid medium. The maximum absorption peaks were 500 nm and 640 nm. The linear range of the method was 1 - I 1 μg/25mL and the detection limitation was 2.82× 10^-10 g/L with the relative standard deviation of 0.05%. This method was of high sensitivity, stability of system and better selectivity. The method was applied to the practice determination of trace nitrite in tap water sample with satisfactory results.