Indirect Determination of Phosphate-ions in Waters with the Reagent Sulfonitrazo DAF

Abstract

An indirect method for the determination of phosphate ions in natural and treated wastewater is proposed, which is based on the formation of molybdophosphate complex (MFC), separating it from excess unbound molybdate by isoamyl acetate extraction, extraction of MFC into weakly alkaline aqueous phase, destruction of MFC and photometric determination of the equivalent amount of molybdate ions with the sulfonitrazo DAF reagent. The technique allows to determine from 0.02 to 0.43 mg dm-3 of phosphate ion (in terms of phosphorus).