The amount of ammonia in the distillates may be measured either by (1)
comparison of the Nesslerized distillates with Nesslerized solutions
containing known quantities of nitrogen as ammonium chloride, or by (2)
comparison of the Nesslerized distillates with permanent standard
solutions in which the colors of Nesslerized standard ammonia solutions
are duplicated by solutions of platinum and cobalt chlorides.