Abstract: 4500-NH₃ A. Introduction

1. Selection of Method

The two major factors that influence selection of the method to determine ammonia are concentration and presence of interferences. In general, direct manual determination of low concentrations of ammonia is confined to drinking waters, clean surface or groundwater, and good-quality nitrified wastewater effluent. In other instances, and where interferences are present or greater precision is necessary, a preliminary distillation step (4500- NH₃ B) is required.

A titrimetric method (4500-NH₃ C), an ammonia-selective electrode method (4500-NH₃ D), an ammonia-selective electrode method using known addition (4500-NH₃ E), a phenate method (4500-NH₃ F), and two automated versions of the phenate method (4500-NH₃ G and H) are presented. Methods 4500-NH₃ D, E, F, G, and H may be used either with or without sample distillation. The data presented in Tables 4500-NH₃:1 and Table 4500-NH_3:3 should be helpful in selecting the appropriate method of analysis.