Summary. Sodium gluconate (CAS 527-07-1) is a neutral salt used as a chelating agent in strongly alkaline cleaning and as a set retarder in concrete. It is not gluconic acid, not an acidifier, and not interchangeable with EDTA or citrate without a trial. This guide is general chemistry for purchasers; it makes no claim that one chemical is better than another, and it is not a specification of our product. We supply technical-grade sodium gluconate in 25 kg bags from Chennai.
Why this comparison comes up
Buyers rarely start by asking for sodium gluconate. They start with a problem: hard-water scale in a bottle washer, iron staining in a caustic CIP line, a concrete mix that sets too fast in summer. Several chemicals can be pointed at those problems, and enquiries often name the wrong one because the names look alike. Gluconic acid, glucono delta-lactone and sodium gluconate share a backbone but behave differently, and EDTA is a different chemistry altogether.
The statements below are textbook, general-knowledge chemistry. They are not SPC specifications and carry no performance guarantee. Your metals, pH, temperature and discharge rules decide the answer, so every change should be proved in a small trial first.
Start with identity: three gluconate-family names
Sodium gluconate is CAS 527-07-1, formula C6H11NaO7, also written sodium D-gluconate or gluconic acid sodium salt. Gluconic acid is a different listing, CAS 526-95-4. Glucono delta-lactone (GDL) is a related compound that turns into gluconic acid when it dissolves in water.
- Sodium gluconate is the neutral salt. Its solution sits close to neutral (general knowledge); the TDS pH limit is 6.2 to 7.8. It is used for its chelating and retarding action, not to lower pH.
- Gluconic acid is the acid. It lowers pH and is used where acidity is wanted, for example some descaling roles.
- GDL acidifies slowly as it hydrolyses. That slow acid release is why it is used where gradual pH fall is needed.
If your formula needs a chelant in a caustic bath, adding an acid-type member of the family works against you. If you need acidity, the salt will not provide it. Always confirm the CAS number on a quote.
Sodium gluconate against EDTA
EDTA is a synthetic aminopolycarboxylate chelant. It binds many metal ions strongly and is widely used in detergents, water treatment and industrial cleaning. Sodium gluconate is a sugar-acid salt. In general terms:
- Alkaline conditions. Gluconate is known for staying effective in strongly alkaline solution, which is why it features in bottle-wash and CIP caustic. Check how your EDTA grade performs at your actual caustic strength.
- Metal range. EDTA binds a broad range of metals strongly. Gluconate is often chosen for specific ions such as calcium and iron in alkaline media. If your problem metal is outside that, a trial may show a gap.
- Environmental profile. Our Safety Data Sheet reports sodium gluconate as readily biodegradable (OECD 301). EDTA is generally regarded as less readily biodegradable than gluconate; check your own discharge limits.
Neither is better in every process. Some formulations combine chelants; a trial decides. We supply both lines; see our EDTA product page.
Sodium gluconate against citrate
Citrate (citric acid and its salts) is an effective, familiar chelant at neutral to mildly acidic or alkaline pH. As pH rises well into the caustic range, as a general rule citrate loses effectiveness against some metals, while gluconate holds up. For formulations that run at mild pH, such as some neutral cleaners, citrate may be enough and may be easier to source. The cut-off depends on the metal and the temperature, so it is a trial question, not a rule.
Sodium gluconate against lignosulphonate in concrete
These two are often confused because both appear in concrete admixtures. In general terms, lignosulphonate is a polymer used as a plasticiser (water-reducing) base, and it can also give some retardation. Sodium gluconate is used as a set retarder and is reported to contribute some water reduction at low doses. Blenders often pair them where more controlled retardation is needed. They are different chemistries with different dose logic. See our sodium ligno sulphonate page.
Quick comparison
| Chemical | What it is and typical role | Watch for |
|---|---|---|
| Sodium gluconate | Neutral salt, CAS 527-07-1; chelant in alkaline media, concrete retarder | Hygroscopic; caking |
| Gluconic acid | Acid, CAS 526-95-4; acid-side descaling roles | Lowers pH; wrong for caustic baths |
| Glucono delta-lactone | Acid precursor for slow pH reduction | Not used as the chelant in caustic baths |
| EDTA | Synthetic aminopolycarboxylate; broad-range chelation | Biodegradability, discharge limits |
| Citrate | Citric acid and salts; mild-pH chelation | Weaker at high pH |
| Lignosulphonate | Polymer plasticiser (water-reducing) base; also gives some retardation, so it is often paired with gluconate for more controllable retardation | Dose and retardation interact with gluconate |
| Source: general knowledge (textbook chemistry); not SPC specification data. Sodium gluconate pH limit and CAS from the SPC Technical Data Sheet SPC-TDS-PWD-072 and SPC product identity record. |
How to choose, step by step
- Write down the problem metal and the pH. Calcium scale in caustic, iron in an alkaline bath and a retarder for a hot-weather mix are three different problems.
- Check what you can discharge. If effluent limits or a customer standard restrict less biodegradable chelants, include that early.
- Check the grade. Our sodium gluconate is technical grade, a white crystalline powder with assay 98.0 to 102.0 %. It is not food or pharma grade, and no liquid form is listed on our TDS.
- Run a bench trial. Change one variable at a time, with your own water, caustic strength and temperature.
- Compare lots. Use the batch Certificate of Analysis supplied with every delivery against the TDS limits (pH 6.2 to 7.8, loss on drying 0.3 % max).
Handling notes for the powder
Sodium gluconate is hygroscopic and cakes if exposed to humidity, so keep bags closed, off the floor, in a cool, dry place; shelf life is 24 months from manufacture in sealed bags. Fine powder can form a combustible dust cloud, and spilled powder is slippery when wet. It is incompatible with strong oxidisers, strong acids, and aluminium in wet alkaline conditions. Read the Safety Data Sheet on the product page, and see how to read an SDS.
Common mistakes to avoid
- Ordering by name alone. Confirm CAS 527-07-1 for the sodium salt.
- Assuming a food-grade claim carries over. E576 is a food-additive designation and does not apply to technical grade.
- Comparing assay headlines. Compare the stated limits and the document they come from, such as a TDS limit of 98.0 to 102.0 % and a lot COA.
- Skipping the trial. A chelant that works in a neutral cleaner may fail in strong caustic, and the reverse can also be true.
What we supply
Supreme Petro Chemicals is an importer and bulk distributor in Chennai, with a head office at Periyamet and a warehouse at Redhills. We supply technical-grade sodium gluconate (CAS 527-07-1) in 25 kg bags to manufacturers across South India. TDS and SDS download from the sodium gluconate page, and a batch Certificate of Analysis is supplied with every delivery. We do not claim our grade outperforms alternatives; your trial decides. For a quote, use the enquiry form with your quantity, location and application. We quote within 4 working hours.