催化动力学光度法测定痕量对苯二胺

在硫酸介质中,在25℃条件下,痕量对苯二胺能催化碘酸钾氧化2-（3,5-二溴-2-吡啶偶氮）-5-二乙氨基酚（3,5-diBr-PADAP）的褪色反应,褪色程度与对苯二胺含量在一定范围内成正比,据此建立了催化动力学光度法测定痕量对苯二胺的新方法。测定波长463 nm,对苯二胺含量在1.5～15 mg/L范围内与吸光度差值ΔA呈线性关系,方法检出限为0.017 mg/L。方法用于环境水体中对苯二胺含量的测定,最大相对标准偏为4.8%,加标回收率为96.4%～105.3%之间。

Determination of Trace p-phenylene Diamine by Catalytic Spectrophotometry

In sulfuric acid and 25 ℃ water bath,based on the catalytic effect of trace p-phenylene diamine on the oxidation discoloring reaction of 2-（3,5-diBr-2-pyridy lazo）-5-diethylaminophenol（3,5-diBr-PADAP）by KIO3,a new simple and sensitive catalytic spectrophotometry was developed for determination of trace p-phenylene diamine.The difference in the absorbance has a quantitative relationship with the concentration of p-phenylene diamine.The wavelength for the determination was 463 nm.A good linear relationship was obtained in the concentration range of 1.5～15 mg/L for p-phenylene diamine with the detection limit of 0.017 mg/L.The method has been applied in determination of p-phenylene diamine in environmental water;the maximum relative standard deviation was 4.8%,and the recovery rate was in the range of 96.4% ～105.3%.