苯酚-次氯酸钠示波极谱法测定水中微量氨

Oscillopolarographic determination of trace amount of NH_3 in water based on the reaction of phenol with hypochlorite

在亚硝基铁氰化钾存在下 ,氨在氢氧化钠介质中与苯酚、次氯酸钠反应 ,其产物靛酚在滴汞电极上产生一灵敏的吸附波 ,NH3-N在 0 .0 0 3～ 0 .2 2 mg/L范围内 ,导数峰电流与其呈良好的线性关系。用于环境水中 NH3-N的测定 ,其相对标准偏差小于 3 % ,回收率在 97%～ 1 0 5 %之间 ,方法具有较好的选择性。

It has been found that the reaction product of NH 3 with phenol and sodiam hypochlorite could produce a sensitive polarographic wave at -0.42V in the presence of NaOH and K 2Fe (CN) 5NO. Linear relationship between derivative wave height and concentration of NH 3 N could be obtained in the range of 0.003～0.22μg/L. The method has been used for determination of NH 3 N in environmental water. The results show that the relative standard deviation is less than 3%, the recovery is 97%～105%, the method is high selective.