Ammonia determination based on indophenol formation with sodium salicylate

An ammonia determination based on formation of a substituted indophenol with sodium salicylate as phenolic reagent has been developed and compared with other methods. Sensitivity and reproducibility are comparable with results obtained in a method where phenol was used, while a number of the disadvantages inherent to the use of phenol are avoided. The salicylate method is specific for NH3N and interferences are generally absent in samples from natural fresh waters. The method can be easily applied for seawater analysis.