氨气敏电极法测定大气中氨

Determination of Atmospheric Ammonia by Sensitive Electrode Method

以H_2SO_4(0.05mol/L)和NH_3(1.00mg/L)的混合溶液作吸收液,采用气敏电极测定大气中氨,发挥了离子选择电极所具有的快速、灵敏及测定范围宽等优点,保证了大气中低浓度氨测定的准确性和可靠性。实验表明,该方法检测限为0.014～0.018mg/m^3,精密度约为14.3％(相对标准偏差),回收率在97％～102％之间。经6个实验室验证的结果,无论是精密度的变异系数或回收率的置信系数,均是可以接受的。该法己被国家环保局认可,作为标准方法颁布。

Using mixed solution (0.05mol/L H2SO4 +1.00mg/L NH3) as absorbent and adopting sensitive electrode method to determine atmospheric ammonia, which exerts its advantages of speed, sensitivity and wide determining range to assure the accuracy and reliability of determining low concentrated ammonia in atmosphere. The experimental result showed that the detecting limit of this method was 0.014 ~ 0.018mg/m3, the accuracy was 14.3% (relative standard deviation) and the recovery rate within 97% ~ 102%. Based on experimental verification from six diferent laboratories both variance coefficient of accuracy and reliable coefficient of recovery rate were acceptable.This method has been approbated and issued as the standard method by the state EPA.