ISO 622:2016规定了测定硬煤、褐煤和焦炭总磷含量的还原磷钼酸盐光度法。规定了两种将磷带入溶液的方法，即用酸从煤或焦灰中提取，或用酸反复氧化煤或焦，以去除含碳物质。

ISO 622:2016 specifies a reduced molybdophosphate photometric method for the determination of the total phosphorus content of hard coal, lignites and coke. Two methods for taking the phosphorus into solution are specified, namely extraction from the coal or coke ash with acid or by repeated oxidation of the coal or coke, by acid, to remove carbonaceous matter.