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Sigma-Aldrich

Citric acid

ACS reagent, ≥99.5%

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Synonym(s):
2-Hydroxy-1,2,3-propanetricarboxylic acid, 2-Hydroxypropan-1,2,3-tricarboxylic acid
Linear Formula:
HOC(COOH)(CH2COOH)2
CAS Number:
Molecular Weight:
192.12
Beilstein:
782061
EC Number:
MDL number:
eCl@ss:
39021801
PubChem Substance ID:

grade

ACS reagent

Quality Level

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 (C2O42-): passes test (limit about 0.003%)
phosphate (PO43-): ≤0.001%
sulfate (SO42-): ≤0.002%

cation traces

Fe: ≤3 ppm
Pb: ≤2 ppm

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)

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General description

Citric acid is an organic acid commonly used as a chelating agent, a buffering agent, for pH adjustment and derivatization.

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.

Legal Information

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

Pictograms

Exclamation mark

Signal Word

Warning

Hazard Statements

Hazard Classifications

Eye Irrit. 2 - STOT SE 3

Target Organs

Respiratory system

Storage Class Code

11 - Combustible Solids

WGK

WGK 1

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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