纳氏试剂光度法测定废水中氨氮的问题讨论

应用纳氏试剂比色法测定废水中的氨氮时，水样显色后稳定时间短，影响测定结果的准确性，针对这一问题进行了实验研究。实验中对主要影响因素Ｉ－和ＯＨ－的浓度变化进行了条件实验，结果表明选用所配的Ⅲ型纳氏试剂（ＫＩ含量为７．５ｇ），可获得稳定的有色胶体，也可采用Ⅰ型纳氏试剂（ＫＩ含量为７．０ｇ）、在中和硼酸后再多加２ｍＬＮａＯＨ（１ｍｏｌ／Ｌ），也可获得稳定的有色胶体。

Discuss of problem about Nash reagent photometry to determine ammonia and nitrogen in sewage

Experiment and research had been conducted,aiming at the problem of influencing measure result accuracy while determining ammonia and nitrogen in sewage by Nash reagent colorimetry for the reason of short stable time after water smple's chromogenic reaction.The main influencing elements,i.e. the concentration changes of I - and OH -,had been tested under conditions.The result showed that the chosen type Ⅲ of Nash reagent with KI content of 7.5g had produced stable colored rubber matrix.In addition,type I of Nash reagent with KI content of 7.0 g had also produced stable colored rubber matrix by means of adding extra 2 mL NaOH (1mol/L) after neutralizing boric acid.