常用海水硝酸盐测定方法的比对研究

Comparison Study of Commonly Used Seawater Nitrate Determination Methods

目前,海洋生态环境问题越来越引起人们的重视,氮磷已成海洋生态水体的主要超标物质,其中海水硝酸盐是无机氮的最主要形式之一。为便于在海水监测工作中选择合适的监测方法,确保硝酸盐监测数据的真实、准确,文章对日常工作中测定海水硝酸盐使用过的镉柱还原法、锌镉还原法、流动分析法进行了比对。得出的结论是不推荐使用锌镉还原法,如确需使用可选择优化后的铵锌镉还原法,使用前应开展方法验证;镉柱还原法是常用的方法,其操作步骤繁琐,测定过程较长,运维成本较低,适合少量样品的测定;流动分析法是当前推荐优先使用方法,其灵敏度高,操作简单,运维成本高,适合大量常规样品测定。

At present,more and more attention has been paid to the problems of Marine ecological environment.Nitrogen and phosphorus have become the main substances exceeding the standard of Marine ecological water bodies,among which seawater nitrate is one of the most important form of inorganic nitrogen.In order to select suitable monitoring methods in seawater monitoring work and ensure the authenticity and accuracy of nitrate monitoring data,the paper compares the cadmium column reduction method,zinc cadmium reduction method and flow analysis method used in daily work to determine nitrate in seawater.The conclusion is that the zinc-cadmium reduction method is not recommended.If it is necessary to use,the optimized ammonium zinc-cadmium reduction method can be selected,and the method should be verif ied before use.Cadmium column reduction method is a commonly used method,which has complicated operation steps,long determination process and low operation and maintenance cost,and is suitable for the determination of a small number of samples.Flow analysis method is recommended as the preferred method at present,which has high sensitivity,simple operation and high operation and maintenance cost,and is suitable for the determination of a large number of routine samples.