营养盐自动分析仪测量海水氨氮盐度效应分析及解决方案探讨

Analysis on the Effect of Measuring Ammonia Nitrogen in Seawater with Automatic Nutritive Salt Analyzer and Discussion on Solutions

以营养盐自动分析仪为研究对象,研究海水氨氮测量过程中海水盐度效应的特点,并在此基础上研究降低盐度效应的方法。采用营养盐自动分析仪测量不同盐度标准溶液,标准曲线线性度都能达到0.999 0以上,说明海水盐度对分析仪标准曲线线性度基本没有影响;随海水盐度增加,标准曲线斜率呈增加趋势。通过对比15条不同盐度标准曲线测量准确性,确定在海水盐度已知情况下选取与被测海水盐度最为相近的人工海水定标能够最大程度降低盐度效应;在海水盐度未知或海水盐度变化较大情况下,以盐度15的人工海水定标,能够最大程度降低盐度效应对氨氮测量结果的影响。

With the automatic analyzer for nutrient salts as the research object, this paper studies the characteristics of seawater salinity effect in the process of measuring ammonia nitrogen in seawater, as well as the approach to reduce salinity effect. When measuring standard solutions with different salinities, the linearities of standard curves from nutritive salt analyzer are over 0.9990, indicating that seawater salinity has broadly no effect on the linearity. With rising seawater salinity, the slope of the standard curve shows an increasing trend. Through analyzing the measuring accuracy of 15 standard curves with different salinities, it is ascertained that when the seawater salinity is known, the salinity effect can be reduced to the maximum extent by selecting the artificial seawater with a salinity similar to the tested seawater for calibration. When the seawater salinity is unknown or changes in a large scope, it is suggested to calibrate the standard curve at the salinity of 15, so as to minimize the influence of salinity effect on ammonia nitrogen measuring results.