The invention provides a method for directly measuring the content of
nitrate in
seawater and application of the method. According to the method,
ammonia-free
seawater is used as a blank solution and a diluted solution, so that the influence of
background factors such as
salinity in a
seawater sample on determination is eliminated, meanwhile, scanning treatment is performed by adopting a second derivative
ultraviolet spectrum method, the interference of other substances near an
ultraviolet absorption peak of
nitrate is eliminated, and the accuracy and selectivity of the method are effectively ensured. The method has the characteristics of good selectivity, wide
linear range, high accuracy and good stability, can quickly and effectively detect the
nitrate content in the seawater sample, and can be used for batch inspection. According to the method, no
masking agent needs to be additionally added, the nitrate content in the sample can be directly measured after
filtration, and the method has the advantages of being small in interference, easy to operate, high in speed, high in
recovery rate, good in precision and the like and is suitable for rapidly and directly measuring the nitrate content in seawater, other
saline water samples and some salt-containing industrial
wastewater.