Phosphorus, total

Inorganic phosphates are compounds of phosphorus and oxygen that occur in many forms and are usually combined with other elements. Phosphoric acid, the common acid of phosphorus, is the main commercial source of inorganic phosphate compounds. Phosphoric acid is made by treating calcium phosphate rock, such as apatite, with sulfuric acid.Phosphoric acid is usually stored and sold as a solution. It is a brown/green viscous liquid with a slight acid odour. It is tribasic, having three replaceable hydrogen atoms. Phosphates are products formed by the replacement of some or all of the hydrogen of phosphoric acid by metals, such as sodium, potassium, calcium and aluminium.