用3，5-diBr-PADAT催化光度法测定水样中亚硝酸根

Catalytic spectrophotometric determination of trace nitrite in water samples with 3,5-diBr-PADAT

在磷酸介质中,根据亚硝酸根催化溴酸钾氧化5-(3,5-二溴-2-吡啶偶氮)-2,4-二氨基甲苯(3,5-diBr-PADAT)的退色反应,建立了催化光度法测定微量亚硝酸根的新方法。亚硝酸根催化3,5-diBr-PADAT退色反应前后在434nm吸收峰产生的吸光度差,与亚硝酸根的浓度呈线性关系,方法的检出限为4.56×10-7mol/L,线性范围1.0×10-7～1.25×10-5mol/L。用于湖水等水样的测定,结果令人满意。

In a H3PO4 medium, a new catalytic spectrophotometric method for the determination of trace amount of nitrite was established using 3, 5-diBr-PADAT. This method was based on the catalytic effect of nitrite on the oxidation reaction of 3,5-diBr- PADAT by KBrO3. Experimental results showed that the absorbance at 434 nm was proportional to the nitrite concentration. The detection limit for nitrite was 4.56 × 10^-7mo1/L. The linear range of the determination was 10^- 7 - 10^- 5 mol/L. The method has been successfully applied to the determination of nitrite in samples of lake water, tap water and mineral water, and the analyrical results were satisfactory.