Flow Injection Analysis of Nitrite Nitrogen in Seawater Introducing Standard Addition Method

A flow injection analysis of nitrite nitrogen (N-NO2-) in the samples which contain relatively high degrees of salt is described. The N-NO2- was optically detected by use of Griess method. Five pseudo-seawater samples containing 40 μg L-1 N-NO2- with 0, 1, 2, 3, or 4% sodium chloride (NaCl) were tested using two quantitative analysis approaches. In an absolute calibration method, approximately 30% of positive errors were found in the presence of NaCl. On the other hand, the errors fell within the range of −2.6 to +7.3% by introducing a standard addition method. The latter method has successfully been applied to the determination of nitrite nitrogen in real seawater and estuary water.