251275

Citric acid

ACS reagent, ≥99.5%

• Synonym(s): 2-Hydroxy-1,2,3-propanetricarboxylic acid, 2-Hydroxypropan-1,2,3-tricarboxylic acid
• Linear Formula: HOC(COOH)(CH₂COOH)₂
• CAS Number: 77-92-9
• Molecular Weight: 192.12
• Beilstein/REAXYS Number: 782061
• EC Number: 201-069-1
• MDL number: MFCD00011669
• UNSPSC Code: 12352100
• eCl@ss: 39021801
• PubChem Substance ID: 24855122
• NACRES: NA.21

Properties

• grade: ACS reagent
• Quality Level: 200
• assay: ≥99.5%
• form: crystals
• expl. lim.: 8 %, 65 °F
• impurities: Substances carbonizable by hot sulfuric acid, passes test
• ign. residue: ≤0.02%
• pKa: (1) 3.13, (2) 4.76, (3) 6.4
• mp: 153-159 °C (lit.)
• anion traces: chloride (Cl^-): ≤0.001%; oxalate (C₂O₄^2-): passes test (limit about 0.003%); phosphate (PO₄^3-): ≤0.001%; sulfate (SO₄^2-): ≤0.002%
• cation traces: Fe: ≤3 ppm; Pb: ≤2 ppm
• functional group: carboxylic acid; hydroxyl
• SMILES string: OC(=O)CC(O)(CC(O)=O)C(O)=O
• InChI: 1S/C6H8O7/c7-3(8)1-6(13,5(11)12)2-4(9)10/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)
• InChI key: KRKNYBCHXYNGOX-UHFFFAOYSA-N
• Gene Information: human ... SRC(6714)

Description

General description

Citric acid is a weak organic acid that is commonly used for pH adjustment, as a chelating agent, as a buffering agent, derivatization and as starting material for the synthesis of citrate esters and other compounds.

Application

Citric acid has been used to prepare:

• Phosphate citrate buffer for use in enzyme-linked immunosorbent assay.
• Citrate-stabilized ceria aqueous sol, which was employed in the synthesis of cerium oxide nanoparticles.
• Citric acid-Na₂HPO₄-buffered stock solution for use in the determination of fecal urease activity.
• Anticoagulant citrate dextrose solution A (ACD-A), which is employed during the isolation of blood-derived endothelial progenitor cells.

Citric acid has also been used:

• In a novel process which allows controlling of the particle size during the synthesis of palladium cuboctahedrons.
• To prepare citric acid-derived carbon nanodots (CNDs) by bottom-up carbonization method.
• As a bi-component chelating agent for the synthesis of Li4Ti₅O₁₂ (lithium titanate oxide) by a novel sol–gel method.

Other Notes

Go to Redi-Dri^™ Product Listing 791725

Legal Information

Redi-Dri is a trademark of Sigma-Aldrich Co. LLC

Safety Information

• pictograms: GHS07
• signalword: Warning
• hcodes: H319,H335
• pcodes: P261 - P264 - P271 - P280 - P304 + P340 + P312 - P305 + P351 + P338
• Hazard Classifications: Eye Irrit. 2 - STOT SE 3
• target_organs: Respiratory system
• Storage Class: 11 - Combustible Solids
• wgk_germany: WGK 1
• flash_point_f: Not applicable
• flash_point_c: Not applicable
• ppe: dust mask type N95 (US), Eyeshields, Gloves