Phosphate can be rapidly and easily titrated thermometrically by adapting the classical gravimetric precipitation reaction with magnesium in the presence of ammonium. This reaction is exothermic and a Mg2+ standard solution can be used as titrant.
This Application Bulletin deals with the determination of phosphate in phosphoric acid and granular fertilizers such as MAP (monoammonium phosphate), DAP (diammonium phosphate), and TSP (triple superphosphate). Results are reported as percentage of P and P2O5.