Definition and Usage Areas of Monosodium phosphate

Monosodium phosphate (MSP), also known as monobasic sodium phosphate and sodium dihydrogen phosphate, is an inorganic sodium compound with dihydrogen phosphate (H2PO4-) anion. One of many sodium phosphates, it is a common industrial chemical. Salt exists in anhydrous form as well as mono- and dihydrates.

The salt is obtained by partial neutralization of phosphoric acid. The pKa value of monosodium phosphate is 6.8-7.2 (depending on the physico-chemical properties in the pKa determination).

Heating this salt above 169 °C gives the corresponding sodium acid pyrophosphate:

2 NaH2PO4 → Na2H2P2O7 + H2O

It should be used in areas with appropriate ventilation. Prolonged and repeated contact with the skin should be avoided, should not be inhaled or swallowed. It should be stored in dry and cool environments. It should be kept away from incompatible substances.

Usage areas

• Animal feed, toothpaste and evaporated milk are added. It is used as a thickening agent and emulsifier.
• Monosodium phosphate is used to detect the presence of magnesium ions in salts.
• It is used as a buffer and emulsifier in foods. It is used as an acid component in dry powdered soft drinks, effervescent powders and lactacids, and as a gelling accelerator in instant puddings to preserve the egg yolk color before cooling.
• It is used in applications such as metal finishing, pH control in acid type metal cleaners, water treatment, detergents, textile, oil drilling mud, penetrating mud treatment, dispersing agent, hardness stabilization, cheese processing (emulsifying properties allow oil to disperse and melt easily).