4-氨基偶氮苯的分光光度法测定

Spectrophotometric Determination of 4-Aminoazobenzene

研究了邻甲氧基苯酚分光光度法测定4-氨基偶氮苯方法的可行性。通过对显色过程中重氮化反应的酸度、时间及氨基磺酸铵用量,偶合反应的介质pH值、温度、稳定时间等影响因素的研究,确定了测定的最佳条件为:在室温下,4-氨基偶氮苯和亚硝酸钠在pH值为2.56时,反应生成重氮盐;在pH值为10.25时,重氮盐与邻甲氧基苯酚偶联显色,重氮化反应时间为30min,显色效果最佳。在优化条件下,在1～50mg.L-1范围内,偶合产物在最大吸收波长505.5nm处吸光值的增加与4-氨基偶氮苯浓度的增加呈良好的线性关系,检出限为(3σ)3mg.L-1。该方法操作简单易行,可有效地应用于4-氨基偶氮苯的快速检测。

The possibility of determining 4-aminoazobenzene by guaiacol spectrophoto- metric method was studied. The obtained optimum conditions for reaction of 4-aminoazo- benzene and sodium nitrite were room temperature and pH= 2.56, and the optimum con- ditions for reaction between diazo salt and guaiacol were pH = 10.25 and reaction time 30min. Under above conditions, the absorbance at 505. 5nm increased proportionallywith the increase of 4-aminoazobenzene concentration in the range of 1-50 mg · L^1 ,and the detection limit（3σ）was 3 mg · L^-. This method could be effectively applied todetermine the level of 4-aminoazobenzene.