A guide to sodium gluconate, what it is, why it outperforms other chelants in alkaline systems, and how it's supplied, from a US-based distributor.
Sodium gluconate (CAS 527-07-1) is the sodium salt of gluconic acid and a chelating agent that binds calcium, iron and aluminium ions, exceptionally well in strongly alkaline conditions where EDTA falters. It is used in food and beverage as additive E576, and in alkaline cleaners, concrete admixtures, metal surface treatment and water treatment. Stratus Chemical supplies food grade and technical/industrial grades in 25 kg bags and supersacks.
| Property | Value |
|---|---|
| Chemical name | Sodium gluconate |
| CAS number | 527-07-1 |
| Molecular formula | C6H11NaO7 |
| Molecular weight | 218.14 g/mol |
| EC / EINECS | 208-407-7 |
| Food additive number | E576 / INS 576 |
| Synonyms | Sodium D-gluconate, gluconic acid sodium salt, monosodium gluconate |
| Appearance | White to light-yellow crystalline powder or granules |
| Grades supplied | Food grade and technical / industrial |
| Packaging | 25 kg bags and supersacks |
Sodium gluconate is the sodium salt of gluconic acid, produced by fermentation of glucose. Its value comes from a specific structural feature: multiple hydroxyl groups positioned to wrap around a metal ion. That gives it strong sequestration of calcium, iron, copper and aluminium.
What sets it apart from most other chelants is where it works best. Sodium gluconate's chelating strength increases in alkaline conditions, and it stays stable in hot, concentrated caustic, an environment in which EDTA and NTA lose effectiveness. Anywhere a process runs strongly alkaline and hot, gluconate is usually the right chelant. It is also readily biodegradable and phosphate-free, which increasingly matters as EDTA faces regulatory pressure.
Sodium gluconate is approved as food additive E576, where it acts as a sequestrant and acidity regulator. It binds trace metal ions that would otherwise catalyse oxidation, discolour a product or destabilise it over shelf life, and it is also used as a mineral carrier. Food grade material is supplied against the appropriate specification with documentation.
In caustic cleaning systems, sodium gluconate sequesters the hardness ions that would otherwise precipitate as scale on equipment and leave spotting or film on cleaned surfaces. It is standard in returnable-bottle wash lines, CIP systems, dairy and brewery cleaning, and heavy-duty industrial degreasers, precisely because it survives the hot caustic those systems run.
Sodium gluconate acts as a set retarder and water reducer. It delays cement hydration, extending working time in hot-weather placement, long hauls and large continuous pours, while allowing a lower water-cement ratio for the same workability, which means higher ultimate strength. The dose is small and the response curve is steep, so overdosing causes excessive retardation. Establish the dose by mix trial.
Used in alkaline derusting and pickling baths, where it complexes iron and keeps it in solution rather than letting it redeposit. Also used in aluminium etching and as a bath additive in electroplating and electropolishing lines.
A sequestrant and scale inhibitor in cooling water and boiler systems, often paired with phosphonates. Its biodegradability makes it attractive where discharge limits are tight.
A scouring and mercerizing aid, holding hardness and metal ions in the caustic bath so they don't interfere with dye uptake or fibre quality.
Chelant selection is mostly a question of pH and environmental profile.
| Factor | Sodium gluconate | EDTA | Citric acid | Phosphonates |
|---|---|---|---|---|
| Best pH range | Alkaline to strongly alkaline | Broad; weakest at high pH | Acidic to neutral | Broad |
| Stability in hot caustic | Excellent | Reduced | Poor | Variable |
| Strength at neutral pH | Moderate | Strong | Moderate | Strong |
| Readily biodegradable | Yes | No | Yes | No |
| Phosphate-free | Yes | Yes | Yes | No |
How to choose. If your system is hot and strongly alkaline, caustic cleaning, bottle wash, alkaline derusting, sodium gluconate typically outperforms EDTA despite EDTA's higher intrinsic binding constants, because EDTA's advantage erodes at high pH. If you need broad-spectrum chelation at neutral pH, EDTA or a phosphonate is usually stronger. If you're reformulating for biodegradability or to drop phosphate, gluconate is the first substitution to test. Many formulations blend gluconate with a phosphonate to cover both regimes.
Stratus supplies sodium gluconate alongside citric acid, HEDP and ATMP, and caustic soda, so a reformulation trial can be sourced from one place.
These appear interchangeably in specifications and they are not interchangeable in use:
If a specification calls for "gluconate" without qualification, ask which one. It is a common source of order errors.
Supplied in food grade and in technical/industrial grades, in 25 kg bags and supersacks. Sodium gluconate is a stable, low-hazard solid; store it dry and sealed to prevent caking. Refer to the SDS for handling and transport classification. COA and SDS are provided with every shipment.
Sodium gluconate is used as a chelating agent in alkaline cleaners and bottle-washing systems, as a set retarder and water reducer in concrete admixtures, in alkaline derusting and metal surface treatment, as a sequestrant in water treatment, and as a scouring aid in textiles.
The CAS number for sodium gluconate is 527-07-1. Its molecular formula is C6H11NaO7 and its molecular weight is 218.14 g/mol. As a food additive it carries the designation E576. Stratus Chemical supplies it in 25 kg bags and supersacks.
Sodium gluconate strongly binds metal ions such as calcium, iron and aluminium, and unusually its chelating strength increases in alkaline conditions. It stays stable in hot concentrated caustic, where many other chelants lose effectiveness, which makes it effective at controlling hard-water minerals and scale in alkaline systems.
It depends on pH. Sodium gluconate outperforms EDTA in hot, strongly alkaline systems such as caustic cleaning and alkaline derusting, where EDTA's effectiveness drops. EDTA is generally stronger across neutral pH ranges. Sodium gluconate is also readily biodegradable while EDTA is not, which is why many formulators evaluate it as an EDTA replacement.
Sodium gluconate is dosed at a small fraction of a percent by weight of cement as a set retarder and water reducer, with the exact dose established by mix trial. The retarding response is steep, so overdosing causes excessive set delay. Ambient temperature, cement chemistry and required working time all affect the dose.
Yes. Sodium gluconate is readily biodegradable and phosphate-free, which is a principal reason formulators select it over EDTA and phosphonate chelants where discharge limits or environmental profile are a concern.
Gluconic acid is the free acid, usually supplied as a solution, and is acidic in use. Sodium gluconate is its sodium salt, near-neutral, supplied as a dry powder, and is the standard choice for alkaline systems. Sodium gluconate is also cheaper to ship because you are not freighting water.
Sodium gluconate is approved as food additive E576, used as a sequestrant and acidity regulator. Stratus Chemical supplies both food grade and technical/industrial grade sodium gluconate, with the corresponding documentation for each.
Stratus Chemical supplies food grade and technical/industrial grade sodium gluconate in 25 kg bags and supersacks, with COA and SDS provided. Share your grade, volume and delivery point and we will respond within one business day.
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