Acidulant formulations
Citric acid is used to adjust acidity in food, beverage, and pharmaceutical formulation contexts. [3]
01
THE ESSENTIALS
Citric Acid in 30 Seconds
This molecule has three acidic –COOH groups around a small carbon framework. It can lose those three acidic protons in separate steps.
Citric acid has three carboxyl groups and one hydroxyl group. Its acid–base and metal-complexing chemistry underlies uses ranging from formulation acidification to laboratory reagents. [1] [3]
Safety at a glance — The listed anhydrous Sigma product 818707 (US listing) is classified for serious eye irritation and possible respiratory irritation (H319/H335). This classification is product-specific; it is not an eye-damage classification or a universal classification for all citric-acid products. [4]
A condensed structural formula keeps the functional groups visible. [1]
Metal complexation
Citrate chemistry is used in sequestration and formulation work. [3]
Chemical intermediates
Citric acid is a precursor to citrate esters, including plasticizer applications. [3]
Commercial availability
The supplier section separates package size, assay, grade, and market context for three named products. [4] [5] [6]
02
GO A LITTLE DEEPER
Understanding Citric Acid
THE SIMPLE EXPLANATION
The functional groups
This molecule has three acidic –COOH groups around a small carbon framework. It can lose those three acidic protons in separate steps. [1]
A LITTLE DEEPER
What the structure changes
The hydroxyl group is an additional –OH, distinct from the hydroxyls inside the carboxyl groups. Commercial citric acid can be anhydrous or a monohydrate; the monohydrate includes water in the crystal and has a different formula weight. [1] [4] [5] [6]
Technical detail Identity, dissociation & specification
The page identity is anhydrous citric acid. Citric acid monohydrate is CAS 5949-29-1, C₆H₈O₇·H₂O, 210.14 g/mol. Citrate salts are separate products. A mass-based recipe must account for the chosen chemical form. [1] [2] [4] [5] [6]
Acid–base reference values describe equilibria under specified conditions. They are not a substitute for a validated formulation or an assay on the purchased lot.
03
MAKE THE CONNECTION
How Citric Acid Compares
Similar names and functional groups do not mean interchangeable chemicals.
SIDE-BY-SIDE COMPARISON
Citric Acid vs Malic Acid
Hydroxytricarboxylic acid
versusHydroxydicarboxylic acid
Fixed comparison for this prototype. Acid selectors are disabled; additional comparisons are coming later.
| Property | Citric Acid | Malic Acid |
|---|---|---|
| Molecular formula | C₆H₈O₇ [1] | C₄H₆O₅ [7] |
| Molecular weight | 192.12 g/mol [1] | 134.09 g/mol [7] |
| Carbon atoms | 6 [1] | 4 [7] |
| Carboxyl groups | 3 [1] | 2 [7] |
| Structure | HOOC–CH₂–C(OH)(COOH)–CH₂–COOH [1] | HOOC–CH₂–CH(OH)–COOH [7] |
| Chemical family | Hydroxytricarboxylic acid [1] | Hydroxydicarboxylic acid [7] |
| Identity focus | Solid · anhydrous identity [1] | Solid · DL identity [7] |
| pKa context | 3.128 / 4.761 / 6.396 (25 °C, water, zero ionic strength) [2] | 3.51 / 5.03 (20 °C; OECD 112) [11] |
Chemical identities are compared here; supplier grades, concentrations, and stereochemical specifications are separate purchasing attributes. pKa values retain their stated conditions; no quantitative solubility ranking is implied.
When Might You Choose One Instead of the Other?
For a citrate-based buffer or a procedure specifying citrate complexation, use the prescribed citrate form. For a malate-based process, use the specified malic stereoisomer and grade. In formulation work, validate the actual performance rather than substitute by equal mass. [1] [3] [7]
Specified starting material
Citric Acid
Match HOOC–CH₂–C(OH)(COOH)–CH₂–COOH and the method’s required chemical form.
Malic Acid
Match HOOC–CH₂–CH(OH)–COOH; verify the identity before substituting a related acid.
Before choosing: match the reaction or formulation, then verify the exact form, grade, assay basis, and impurities. These contexts do not establish suitability for an industrial or regulated application.
04
FROM STRUCTURE TO APPLICATION
What Is Citric Acid Used For?
Acidulant formulations
Citric acid is used to adjust acidity in food, beverage, and pharmaceutical formulation contexts. The listed laboratory products do not establish suitability for those regulated uses. [3]
Metal complexation
Citrate chemistry is used in sequestration and formulation work. Metal binding depends on pH, metal identity, and the citrate form. [3]
Chemical intermediates
Citric acid is a precursor to citrate esters, including plasticizer applications. Ester properties must not be attributed to the free acid. [3]
06
SOURCE WITH CONTEXT
Citric Acid Suppliers
Compare specific products and package options. Listings are not ranked recommendations.
3 suppliers · 3 products · 6 package listingsLatest supplier check: October 3, 2026
Package sizes stay grouped under the supplier product. Assay methods, product forms, and regional markets remain visible. Specify anhydrous or monohydrate, assay basis, and the required application specification.
Scroll horizontally if needed. Supplier and package identity stay visible.
| Supplier | Product / Grade | Purity / Assay | Package Size | Public Price | Normalized Price | Documentation | Last Checked | Action |
|---|---|---|---|---|---|---|---|---|
| Sigma-AldrichCitric Acid | For synthesis · anhydrous8187071000 | ≥99% (alkalimetric) | 1 kg | $90.90USD · US public price | Not comparedGrades, assay bases, or forms differ | Document notes: Sigma-Aldrich
| View Product: Sigma-Aldrich, 8187071000 (opens new tab) | |
| For synthesis · anhydrous8187075000 | ≥99% (alkalimetric) | 5 kg | $342.00USD · US public price | Not comparedGrades, assay bases, or forms differ | View Product: Sigma-Aldrich, 8187075000 (opens new tab) | |||
| TCICitric Acid | Check supplierC1949Anhydrous · CAS 77-92-9 | >98.0% (neutralization titration) | 500 g | $34.00USD · US public price | Not comparedGrades, assay bases, or forms differ | Document notes: TCI
| View Product: TCI, C1949 (opens new tab) | |
| FUJIFILM WakoCitric Acid | Guaranteed Reagent · monohydrate031-03492CAS 5949-29-1 · C₆H₈O₇·H₂O · 210.14 g/mol | ≥99.5% (mass/mass, titration) | 25 g | ¥1,500JPY · Japan suggested price (tax excluded) | Not comparedDifferent currency / market | COA lookup on product page (opens new tab)SDS PDF · Japan/JIS English (opens new tab)COOCheck supplier Document notes: FUJIFILM Wako
| View Product: FUJIFILM Wako, 031-03492 (opens new tab) | |
| Guaranteed Reagent · monohydrate035-03495CAS 5949-29-1 · C₆H₈O₇·H₂O · 210.14 g/mol | ≥99.5% (mass/mass, titration) | 500 g | ¥2,500JPY · Japan suggested price (tax excluded) | Not comparedDifferent currency / market | View Product: FUJIFILM Wako, 035-03495 (opens new tab) | |||
| Guaranteed Reagent · monohydrate031-03497CAS 5949-29-1 · C₆H₈O₇·H₂O · 210.14 g/mol | ≥99.5% (mass/mass, titration) | 20 kg | Price on request | Not comparedDifferent currency / market | View Product: FUJIFILM Wako, 031-03497 (opens new tab) |
Sigma-Aldrich
Citric Acid
For synthesis · anhydrous
1 kg
8187071000- Public price
- $90.90USD · US public price
- Normalized price
- Not comparedGrades, assay bases, or forms differ
5 kg
8187075000- Public price
- $342.00USD · US public price
- Normalized price
- Not comparedGrades, assay bases, or forms differ
Documentation
Document notes: Sigma-Aldrich
- A product-specific certificate retrieval option was visible; no lot certificate was reviewed. Open the product page and use its certificate section.
- A current regional SDS was not verified in this pass.
- Origin-document availability was not verified. Country of origin is unverified and is not inferred.
Last checked:
TCI
Citric Acid
Check supplier
Anhydrous · CAS 77-92-9
500 g
C1949- Public price
- $34.00USD · US public price
- Normalized price
- Not comparedGrades, assay bases, or forms differ
Documentation
Document notes: TCI
- A product-specific certificate retrieval option was visible; no lot certificate was reviewed. Open the product page and use its certificate section.
- A current regional SDS was not verified in this pass.
- Origin-document availability was not verified. Country of origin is unverified and is not inferred.
Last checked:
FUJIFILM Wako
Citric Acid
Guaranteed Reagent · monohydrate
CAS 5949-29-1 · C₆H₈O₇·H₂O · 210.14 g/mol
25 g
031-03492- Public price
- ¥1,500JPY · Japan suggested price (tax excluded)
- Normalized price
- Not comparedDifferent currency / market
500 g
035-03495- Public price
- ¥2,500JPY · Japan suggested price (tax excluded)
- Normalized price
- Not comparedDifferent currency / market
20 kg
031-03497- Public price
- Price on request
- Normalized price
- Not comparedDifferent currency / market
Documentation
COA lookup on product page (opens new tab)SDS PDF · Japan/JIS English (opens new tab)COOCheck supplier
Document notes: FUJIFILM Wako
- A product-specific certificate retrieval option was visible; no lot certificate was reviewed. Open the product page and use its certificate section.
- The linked Japan/JIS English SDS covers the displayed product codes. Confirm the current local version.
- Origin-document availability was not verified. Country of origin is unverified and is not inferred.
Last checked:
Documentation evidence
COA = Certificate of Analysis · SDS = Safety Data Sheet · COO = Certificate of Origin.
Lookup means a retrieval option was visible, not that a lot certificate was reviewed. Check supplier means availability or the applicable document was not verified.
Prices may vary by quantity, account, contract, geography, and availability. These products have different grades, assay bases, or forms; no normalized comparison is shown. Foreign-market prices are reference listings only. No currency conversion, mass-to-volume conversion, or ranking is applied. Confirm equivalent specifications and a current quote before comparison. [4] [5] [6]
Verification limits & placement policy
Use the condition-defined NIST pKa values for this reference. Quantitative supplier solubility entries remain insufficiently characterized for solution design; confirm the measurement basis and conditions for the selected form.
Only the displayed identity, specification, packages, public prices and stated documentation evidence were reviewed. Current stock, lead times, shipping eligibility, contract pricing, lot certificates, and regulatory suitability are unverified.
There are no paid placements. Future paid listings will show “Sponsored” in both views; payment will not determine chemistry interpretation or imply a ranking.
07
PLAN A LARGER ORDER
Need Citric Acid in Bulk?
Turn your requirements into a clear supplier brief.
Bulk RFQ feature — coming soon. Prototype form: submissions are not currently sent to suppliers. Use sample details to prepare an on-screen brief.
Prepare a bulk request Prototype form
08
A BUYER’S CHECKLIST
Before You Buy Citric Acid
Selections remain only while this page is open.
09
FOR YOUR REFERENCE
Citric Acid Technical Reference
Identity, product reference properties, and handling context.
Identification Names, formula & identifiers
- Principal CAS
- 77-92-9
- Identity focus
- Solid · anhydrous identity
- Formula
- C₆H₈O₇
- Molecular weight
- 192.12 g/mol
- IUPAC name
- 2-hydroxypropane-1,2,3-tricarboxylic acid
- Connectivity SMILES
- C(C(=O)O)C(CC(=O)O)(C(=O)O)O
- PubChem CID
- 311
Connectivity SMILES describes connectivity; it is not an independent stereochemical assignment. CAS and product-form distinctions are supported by the supplier listings. [1] [4] [5] [6]
Physical Properties Product references & conditions
Citric acid is very soluble in water, but supplier quantitative values use differing or incompletely specified measurement bases and conditions. No recommended saturation concentration is derived from them. [4] [5]
Hydrate, concentration, stereoisomer, and temperature can change the relevant specification. Product reference data are not a reviewed lot certificate.
Acid/Base Properties Verified values & missing data
Reference pKa: 3.128 / 4.761 / 6.396 (25 °C, water, zero ionic strength). [2]
Use the condition-defined NIST pKa values for this reference. Quantitative supplier solubility entries remain insufficiently characterized for solution design; confirm the measurement basis and conditions for the selected form.
Temperature, ionic strength, and the use of activities versus concentrations matter in quantitative work. These reference values are not buffer recipes.
Safety at a Glance Product-specific hazards
The listed anhydrous Sigma product 818707 (US listing) is classified for serious eye irritation and possible respiratory irritation (H319/H335). This classification is product-specific; it is not an eye-damage classification or a universal classification for all citric-acid products. [4]
Hazard classifications can vary by concentration, formulation, supplier and jurisdiction. Review the SDS for the exact product before handling. This summary does not replace the SDS.
Supplier safety information and SDS retrieval (opens new tab) · FUJIFILM Wako SDS PDF · Japan/JIS English (opens new tab)
A product-page safety classification is not verification of every regional SDS. Confirm product code, chemical form and current local document.
Review supplier documentation10
COMMON QUESTIONS
Citric Acid FAQ
What distinguishes Citric Acid?
This molecule has three acidic –COOH groups around a small carbon framework. It can lose those three acidic protons in separate steps. [1]
How does it differ from Malic Acid?
Citric acid has three carboxyl groups; malic acid has two and a different carbon skeleton. Their shared use as acidulants does not make their buffering, complexing, or sensory behavior identical. [7]
What must a buyer specify?
Specify anhydrous or monohydrate, assay basis, and the required application specification. [4]
Are the listed products directly price-comparable?
No. The table retains differing grades, assay bases, forms, and markets. No normalized ranking or currency conversion is applied. [5]
What reference data still need checking?
Use the condition-defined NIST pKa values for this reference. Quantitative supplier solubility entries remain insufficiently characterized for solution design; confirm the measurement basis and conditions for the selected form.
Can I request a bulk quote here?
The RFQ is a prototype that prepares an on-screen brief. Nothing is sent to suppliers. Confirm actual bulk terms directly with the supplier.
11
TRACE THE INFORMATION
Sources & Editorial Notes
Identity and compiled reference values are separated from supplier-specific specifications. Structural comparisons and buyer guidance are editorial interpretation. Sources were checked October 3, 2026; supplier information can change.
- PubChem · chemical identity (opens new tab)
Official PUG REST identity record: formula, molecular weight, IUPAC name, and connectivity SMILES.
- NIST · Citric acid aqueous ionization (opens new tab)
Goldberg, Kishore and Lennen (2002), table 7.22: evaluated aqueous pKa at 25 °C and zero ionic strength.
- PubChem · applications (opens new tab)
Compiled application references; uses of derivatives are distinguished from direct use of the acid.
- Sigma-Aldrich · commercial product (opens new tab)
Direct product listing checked October 3, 2026. Product-specific grade, assay, package, public price and documentation retrieval evidence. Product-page safety information applies to the identified product and regional listing, not every grade or jurisdiction.
- TCI · commercial product (opens new tab)
Direct product listing checked October 3, 2026. Product-specific grade, assay, package, public price and documentation retrieval evidence. Product-page safety information applies to the identified product and regional listing, not every grade or jurisdiction.
- FUJIFILM Wako · commercial product (opens new tab)
Direct product listing checked October 3, 2026. Product-specific grade, assay, package, public price and documentation retrieval evidence. Product-page safety information applies to the identified product and regional listing, not every grade or jurisdiction.
- Malic Acid · identity (opens new tab)
Primary comparison identity. Explanations of structural differences are editorial interpretation of verified identities.
- Tartaric Acid · identity (opens new tab)
Related chemical identity; relevance is based on structure or the stated application relationship.
- Lactic Acid · identity (opens new tab)
Related chemical identity; relevance is based on structure or the stated application relationship.
- Succinic Acid · identity (opens new tab)
Related chemical identity; relevance is based on structure or the stated application relationship.
- Malic Acid · acid–base reference (opens new tab)
The primary comparison’s pKa source; reference conditions are preserved.
- OpenStax · Citric acid cycle (opens new tab)
Succinate and fumarate in the citric acid cycle; salts/ions are distinguished from purchased free acids.
Review limits
Use the condition-defined NIST pKa values for this reference. Quantitative supplier solubility entries remain insufficiently characterized for solution design; confirm the measurement basis and conditions for the selected form.
This informational prototype is not a supplier, quotation service, or endorsement of a product’s fitness for an application. Buyers should verify the applicable specification, certification, and regulatory requirements for their intended use.