室内空气中氨气快速测定方法的研究

Rapid determination method on the ammonia in tube air

目的 探讨室内空气中微量氨的快速检测方法。方法 利用纳氏试剂与氨气显色的原理 ,测定氨气含量。对不同的实验条件进行了对比选择。结果 筛选出了最佳实验条件 :其玻璃管内径为 2 2mm ,吸附载体为 80～ 10 0目的活化硅胶酒石酸氢钾的混合物 (3∶1) ,采气速度 0 0 4L/min ,采样时间 5min ,采样量 0 2L ,显色时间 3min。实验测定表明 :检测管显色强度与氨气浓度呈线性关系 ;测定灵敏度较高 ,最低显色浓度为 0 2mg/m3 ;重现性较好 ,在最低显色浓度下 ,5次测定值的变异系数为 12 8% ,小于 15 % ,平均相对误差为 8 8% ,小于 15 % ,一次测定最大相对误差为 19 5 % ,小于 2 5 % ,测定符合GB72 3 0— 87的要求。有机胺、酸性气体H2 S、HCHO产生干扰。检测管的使用寿命为 6个月。结论 该方法对室内环境中氨的浓度可快速检测 ,操作简便 ,易于携带 ,适合一般家庭使用。

To study a rapid determination method on the ammonia in tube air.Nessler reagent and the principle of reaction under the condition of alkali to produce color were applied to determine the content of ammonia. Different experimental conditions were compared.The best experimental condition was chosen: with the internal diameter of glass tube of 2.2mm,the absorbent carrier was a mixture of active silica gel of 80～100 mesh and potassium hydrogen tartrate (3:1), the sampling speed, time and volume were 0.04L.min, 5 min, and 0.2L respectively, the indicating time was 3 min.The result showed that the color intensity of the test tube has linear interrelation with the concentration of ammonia, determination sensibility was high, the lowest concentration was 0.2 mg/m 3. Repeatability was good. At the lowest concentration, the coefficient of variation determined for 5 times was 12.8%, which was lower than 15%. The average relative standard error was 8.8%, which was lower than 15%. The maximum relative standard error was 19.5%, which was lower than 25%. The determination meets the command of GB7230-87. Organic amine, acid gas as H 2S and HCHO have disturbance. The longevity of the determination tube was 6 months.[Conclusion]This method is rapid, simple to determine the density of indoors ammonia, and it is portable to be generally used at home.