对氨基苯磺酸重氮化偶联反应的光谱特性及其分析应用

Study on the Spectral Characteristic of the Diazotization-Coupling with Sulfanilic Acid and Its Analytical Application

在稀盐酸介质中,NO-2与对氨基苯磺酸重氮化后与二盐酸 1 萘基乙二胺偶联生成紫红色偶氮染料,在碱性介质中染料的最大吸收波长位于500nm,表观摩尔吸光系数为2 6×104L·mol-1·cm-1.据此建立了在碱性介质中测定痕量亚硝酸根的吸光光度法.NO-2的浓度在0～2 8mg/L范围内符合比耳定律,对于NO-2的检出限为2 6μg/L.方法用于环境水样、蔬菜、香肠和合成水样中NO-2的测定,回收率为94 0%～105 0%.

Nitrite was diazotized with sulfanilic acid and followed by coupling with N-(1-naphthyl) ethylenedia mine dihydrochloride to produce a red azo-compound in dilute hydrochloric acid medium. The azo-compound has a maximum absorption at 500 nm in alkaline medium and the apparent molar absorptivity is 2.6×10~4 L·mol^(-1)·cm^(-1). Based on the spectral characteristic of the azo-compound in various medium, a new method for the determination of trace amounts of nitrite was developed in alkaline medium. The Beer's law is obeyed for nitrite in the range of 0 to 2.8 mg/L and the detection limit is 2.6 μg/L. The method has good selectivity and has been applied to the determination of nitrite in environmental water, vegetable samples, sausage and synthetic samples with satisfactory results and the recovery for nitrite is 94.0%-105.0%.