Reference number
ISO 2999:1974
ISO 2999:1974
© ISO 2025
ISO 2999:1974
Sodium pyrophosphate for industrial use — Estimation of pyrophosphate content — Potentiometric method
Edition 1
1974-12
1974-12
Retirada
Resumen
Applicable to products containing at least 90 % (m/m) of tetrasodium pyrophosphate and in the absence of more condensed forms of phosphates. The reaction based on conversion of tetrasodium pyrophosphate to disodium dihydrogenpyrophosphate by addition of hydrochloric acid. Introduction of zinc sulfate in solution for precipitation of zinc pyrophosphate and formation of sulphuric acid. Potentiometric titration of the sulphuric acid formed with standard volumetric sodium hydroxide solution. Has also been approved by the IUPAC.