规定了一种基于试样与碳酸钠和硼酸熔融并在高氯酸溶液中溶解，然后形成磷钼酸铵络合物并用乙酸异丁酯萃取络合物的方法。溶液被乙炔/一氧化二氮火焰吸收，通过测量钼空心阴极灯发出的379,8 nm线的吸光度来确定钼，从而确定磷。

Specifies a method based on the fusion of a test portion with sodium carbonate and boric acid and dissolution in perchloric acid solution, followed by formation of the ammonium molybdophosphate complex and extraction of the complex with isobutyl acetate. The solution is absorbed into an acetylene/dinitrogen monoxide flame and the molybdenum, and hence the phosphorus, is determined by measuring the absorbance of the 379,8 nm line emitted by a molybdenum hollow-cathode lamp.