Monosodium citrate

Monosodium citrate (CAS 18996-35-5), also known as Sodium dihydrogen citrate and designated E331i, is the monobasic sodium salt of citric acid used across food, pharmaceutical, and industrial applications. It functions primarily as a pH buffer, acidulant, and chelating agent, offering precise control over acidity in formulations where stronger acidification or tighter buffering capacity is required than trisodium citrate provides.

In food and beverage manufacturing, it acidulates and buffers carbonated drinks, fruit preparations, and dairy-based products where controlled tartness and stability are priorities for the final product. Pharmaceutical formulators use it to establish and maintain pH in oral solutions, effervescent tablets, and topical preparations. In personal care, it adjusts pH in creams, gels, and cleansing products.

It also works by sequestering metal ions that would otherwise destabilize the formulation. Water treatment applications rely on its chelating properties to complex calcium and magnesium ions effectively. This process prevents scale formation in process systems and industrial equipment. Monosodium citrate is supplied as a white crystalline powder or granule depending on the specific application requirements.

Standard grades include food-grade meeting FCC specifications and pharmaceutical-grade conforming to USP and Ph. Eur. monographs. Technical grade is available for industrial and water treatment use. These industrial grades are suitable where food or pharma compliance is not required. The material provides consistent performance across a wide range of chemical and manufacturing environments.