As the phosphate radical can react with ammonite vanadate molybdate to form phosphorus molybdenum heteropoly acid in the medium of nitric acid(1+9), the phosphorus can be determined by color reaction.

• 在硝酸(+)液中,磷酸根与钒钼酸铵形成稳定的磷钼钒络合物,经显色后可测定磷。