Citric acid

ACS reagent, ≥99.5%

Linear Formula:
CAS Number:
Molecular Weight:
Beilstein/REAXYS Number:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


ACS reagent



expl. lim.

8 %, 65 °F


Substances carbonizable by hot sulfuric acid, passes test

ign. residue



(1) 3.13, (2) 4.76, (3) 6.4


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




InChI key


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.


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.


5, 100, 500 g in poly bottle
1, 2.5 kg in poly bottle
12 kg in fiber drum

Legal Information

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


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Hazard Statements

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis
Certificate of Origin
Investigation of Size-Dependent Plasmonic and Catalytic Properties of Metallic Nanocrystals Enabled by Size Control with HCl Oxidative Etching.
Li B, et al.
Small, 8(11), 1710-1716 (2012)
Cerium fluoride nanoparticles protect cells against oxidative stress.
Shcherbakov AB, et al.
Materials Science & Engineering. C, Materials For Biological Applications, 50, 151-159 (2015)
Xiaorong Dai et al.
PloS one, 9(11), e110402-e110402 (2014-11-15)
Ammonia emission from animal production is a major environmental problem and has impacts on the animal health and working environment inside production houses. Ammonia is formed in manure by the enzymatic degradation of urinary urea and catalyzed by urease that...
Citric Acid
Lopez-Garcia, R
Kirk-Othmer Encyclopedia of Chemical Technology (2010)
Juan M Melero-Martin et al.
Methods in enzymology, 445, 303-329 (2008-11-22)
Rapid and complete vascularization of ischemic tissues and thick engineered tissues is likely to require vasculogenesis. Therefore, the search for clinically relevant sources of vasculogenic cells and the subsequent development of experimental models of vasculogenesis is of utmost importance. Here...

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