Disodium hydrogen phosphate dodecahydrate

Disodium hydrogen phosphate dodecahydrate (CAS 10039-32-4), commonly abbreviated as DSP, is the fully hydrated crystalline form of dibasic sodium phosphate.

Where is Disodium hydrogen phosphate dodecahydrate used?

• Pharmaceutical manufacturing: prepares buffer solutions and stabilizes injectable formulations where precise pH control affects shelf life and efficacy
• Food processing: sequestrant in processed cheese, dairy products and cured meats, controlling texture and preventing fat separation
• Water treatment: adjusts alkalinity and inhibits scale formation in distribution systems and boiler feed water
• Detergent and cleaning formulations: phosphate-based sequestration of calcium and magnesium ions maintains performance in hard water
• It functions as a pH buffer, sequestrant and stabilizing agent.

Formulation notes

• Dibasic sodium phosphate is also available as the anhydrous, monohydrate, dihydrate and heptahydrate forms, in addition to the dodecahydrate.

Typical specification

• For the dodecahydrate form, the P2O5 content is 19%.
• Available in Extra Pure grade.
• Practically insoluble in alcohol.

Regulatory status

• Has the food additive INS number 339(ii).
• Covered by a European Pharmacopoeia monograph.
• Under ADR 2025, not subject to dangerous goods transport regulations.

Storage, packaging and handling

• No special storage requirements apply.

Frequently asked questions about Disodium hydrogen phosphate dodecahydrate

What loss on drying is required for the USP/NF grade of disodium hydrogen phosphate dodecahydrate?

The USP/NF grade requires a loss on drying between 55.0% and 64.0%.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.