Monosodium phosphate

Monosodium phosphate (CAS 7558-80-7), commonly abbreviated as MSP and designated E339i in food applications, is an inorganic phosphate salt used across food, pharmaceutical, and industrial water treatment sectors.

Sodium phosphate monobasic is its recognized trade form, available in both anhydrous and hydrated versions that serve distinct formulation requirements. Its primary commercial function is pH buffering and sequestration of metal ions.

In water treatment, MSP controls scale formation and corrosion in boiler and cooling systems by sequestering calcium and magnesium ions. This prevents deposits that would otherwise accumulate on equipment surfaces over time.

Food manufacturers use it as a buffering and emulsifying agent in processed cheeses, cured meats, and beverage formulations. Precise pH control in these applications directly affects the final texture and shelf stability of the product.

Pharmaceutical producers rely on MSP to prepare buffer solutions for parenteral formulations, oral dosage forms, and laxative preparations. Consistent ionic strength is critical for maintaining the stability of these medical products.

It also functions as a nutrient source in fermentation media, supporting microbial growth in industrial bioprocesses. MSP is supplied as a white crystalline powder or granule in both anhydrous and monohydrate forms.

Standard grades include food-grade (FCC), USP, and technical, with food and pharmaceutical grades meeting purity specifications. These standards support regulatory compliance in finished products across global markets.