适用于五氧化二磷含量为0.005%（m/m）至0.05%（m/m）的产品。根据ISO 5444测定质量损失的残留物用于制备试样。在稀盐酸和硝酸溶液中溶解。黄色钒钼酸盐的形成和在约420 nm波长下的分光光度测量。根据测量的吸光度计算含量。

Applicable to products having contents, expressed as phosphorus pentoxide, of 0.005 % (m/m) to 0.05 % (m/m). The residue from the determination of the loss of mass according to ISO 5444 is used to prepare the test sample. Dissolution in dilute hydrochloric acid and nitric acid solutions. Formation of the yellow molybdovanadate and spectrophotometric measurement at a wavelength of about 420 nm. Calculation of the content from the measured absorbance.