水杨酸分光光度法测定水中氨氮

Determination of ammonia nitrogen in water by salicylic acid spectrophotometry

在HJ 536-2009基础上建立水杨酸分光光度法测定水中氨氮并对其优化。显色剂由水杨酸钠替代水杨酸和氢氧化钠,氢氧化钠调整游离碱浓度方式由液体改为固体,质量工作曲线法改为浓度直读法。结果表明,方法优化后的氨氮质量浓度在0~1.000 mg/L范围内与吸光度线性良好,相关系数r为0.99996,优化前后地下水测定值无显著性差异。取地下水、污水及0.500 mg/L和0.875 mg/L的标准样品测定结果,相对标准偏差为0.80%~2.91%(n=10),相对误差为0.34%~1.0%,加标回收率为95.2%~100.4%。优化后方法便于样品溶解,显色完全,测定快速准确,无毒且安全环保,能有效降低人工劳动强度并简化分析步骤。

A salicylic acid spectrophotometric method was established to determine and optimize environmentally friendly ammonia nitrogen based on HJ 536-2009.The developer used sodium salicylate instead of salicylic acid and sodium hydroxide.The method of adjusting the free alkali concentration of sodium hydroxide was changed from liquid to solid,and the mass working curve method was changed to direct concentration reading method.The results showed that the optimized ammonia nitrogen concentration had good linearity with the absorbance in the range of 0-1.000 mg/L,and the correlation coefficient was 0.99996.There was no significant difference between the groundwater measurement results before and after optimization.Groundwater,sewage,standard samples with the concentration of 0.500 mg/L and 0.875 mg/L for precision were determined and the relative standard deviation(n=10)was 0.80%-2.91%,the relative error was 0.34%-1.0%,and the recovery rate was 95.2%-100.4%.The optimized method is easy to dissolve the sample,complete color development,rapid and accurate determination,non-toxic,safe and environmentally friendly,which effectively reduce the labor intensity and simplify the analysis steps.