纳氏试剂分光光度法测定氨氮前处理方法的改进研究

Improvement of Pretreatment Method for Determination of Ammonia Nitrogen by Nessler Reagent Spectrophotometry

纳氏试剂法测定水中氨氮时常采用预蒸馏的前处理方法,国标规定使用硼酸溶液作为蒸馏吸收液,但在蒸馏结束之后需要进行pH值的调整,增加工作难度。文章使用0.005 mol/L的硫酸溶液作为蒸馏吸收液进行了初步的方法确认研究,测定了3组实际样品加标回收和3组标准样品,结果表明实际样品的加标回收率在95%~105%之间,标准样品的测定值均在保证值内,6组样品的相对标准偏差均在5%以内,准确度和精密度均满足质量控制要求,可以替代硼酸溶液使用。

The ammonia nitrogen method is often used by the pre-distillation method of nano-distillation.The national standard stipulates that the use of boric acid solution as the distillation absorption solution,but the pH value needs to be adjusted after the distillation is finished,which increases the diff iculty of work.In this paper,0.005 mol/L of sulfuric acid solution as distilled absorption solution,3 actual samples with standard recovery and 3 standard samples showed that the standard recovery rate is between 95% and 105%,standard samples are guaranteed,the relative standard deviation of 6 samples is within 5%,both accuracy and precision Meet the quality control requirements,and can replace the boric acid solution for use.