纳氏试剂光度法测定不同盐度海水样品中的氨氮时，样品中复杂的盐类成分会导致混浊或沉淀出现。针对此问题，本研究依据不同盐度海水样品，通过调节掩蔽剂酒石酸钾钠溶液的用量消除海水中钙、镁离子的干扰。结果表明，在试验条件下，1%的酒石酸钾钠溶液可用于盐度小于17.3‰的样品中氨氮测定；2%的酒石酸钾钠溶液可用于盐度在4.5~34.1‰的样品中氨氮测定；方法的线性范围为0.1~8.0mg.L^-1，检出限为0.03mg.L^-1；样品加标回收率在96.0~105%之间，平行样的标准偏差小于3.94%。该方法小体积操作简单、环保，试剂用量少，线性范围广，且灵敏度、精确度、准确度均好。

The complex salt components in seawater or other salty water will lead to turbidity or precipitation in the measurement of ammonia nitrogen by using Nessler's reagent colorimetric method. In this study, the interference of calcium and magnesium ions in seawater was eliminated by adjusting the dosage of potassium sodium tartrate as masking agent according to seawater samples with different salinity. The results indicate that 1% potassium sodium tartrate solution can be used for the determination of ammonia nitrogen in samples with salinity below 17.3‰ while 2% can be used for the samples with salinity between 4.5‰ to 34.1‰ under experimental conditions. The detection range of the approach was 0.1~8.0mg.L^-1,detection limit was 0.03mg.L^-1. The spiked recoveries of samples ranged from 96% to 105%, and the standard deviation of parallel samples was under 3.94%. The approach has the advantages of simple operation, wide linear range, good performance in sensitivity and accuracy.