丙烯基硫脲和钼酸钠对紫外分光光度法和酚二磺酸光度法测定硝态氮的影响

Effects of Allylthiourea and Sodium Molybdate on Determination of Nitrate

引入抑制剂是研究自然界氮循环的常用手段,然而抑制剂的存在可能会对某些指标(如硝态氮)的测定产生不利影响。实验结果表明,紫外分光光度法测定硝态氮的结果易受干扰物质(抑制剂)的影响,其中丙烯基硫脲(ATU)对于硝态氮测定结果的影响难以校正或消除,钼酸钠在220nm波长处的光谱吸收峰对硝态氮的吸收峰产生了覆盖,导致其测定结果偏差大;酚二磺酸光度法不易受干扰物质影响,在丙烯基硫脲或钼酸钠存在时测定结果稳定可信,可作为硝态氮测定方法使用。

The introduction of inhibitors is a common method in studying nitrogen cycling,and the presence of inhibitors may have adverse effects on the determination of certain indicators,e.g.nitrate nitrogen.Results showed that ultraviolet spectrophotometry is vulnerable to extraneous interference.The influence of allylthiourea(ATU)on the determination of nitrate nitrogen is difficult to correct or eliminate,and the spectral absorption peak of sodium molybdate at 220 nm overlapped with the absorption peak of nitrate nitrogen,thus leading to a great deviation of the latter results.In contrast,nitrate-spectrophotometric method with penol disulonic acid is not easily disturbed by extraneous substances and the results are stable and reliable with the introduction of allyl thiourea or sodium molybdate,respectively.Therefore,nitratespectrophotometric method with penol disulonic acid can be used as a reliable method for nitrate nitrogen determination.