Division 4.8 Reagent for phosphate determination:F1

dissolve 20 g of ammonium molybdate (CAS 12054-85-2), (NH ₄ ) ₆ Mo ₇ O ₂₄ .4H ₂ O in 400 ml water at 50 ^o C;

dissolve, in another vessel, 1 g of ammonium vanadate (CAS 7803-55-6), NH ₄ VO ₃ , in 300 ml hot water, allow to cool, then add 140 ml of concentrated nitric acid (CAS 7697-37-2). Combine the cooled solutions in a 1 000 ml volumetric flask and make up to the 1 000 ml mark.