The phosphate widely used in detergents is an inorganic compound STPP, that is sodium tripolyphosphate Na5P3O10.

STPP is made by combining sodium (as in table salt) with phosphate (in phosphoric acid) extracted from naturally occurring phosphate rock, or from recycled phosphate sources (bone, phosphate recovered from sewage or animal wastes …).

STPP is an authorised food ingredient under US Federal (FDA) legislation (sec. 182.1810) and under EU legislation (Directive 95/2), registered as E451(i).

STPP is identified as follows: CAS-No 7758-29-4, EINECS No. 231-838-7It is also referred to as: pentasodium triphosphate or triphosphoric acid pentasodium salt.

STPP contains (dry weight)

  • 68,8% phosphate P2O4
  • 57.9% P2O5
  • 25.3% phosphorus (P)
© 2017 Global Phosphate Forum