251275 Sigma-Aldrich

Citric acid

ACS reagent, ≥99.5%



Related Categories ACS Grade Buffers, Acids, Acids & Bases, Analytical/Chromatography, Biochemicals and Reagents,
grade   ACS reagent
assay   ≥99.5%
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
Gene Information   human ... SRC(6714)



1, 2.5 kg in poly bottle

12 kg in fiber drum

5, 100, 500 g in poly bottle


Citric acid has been used:
• To prepare the 0.25M phosphate citrate buffer for use in enzyme-linked immunosorbent assay.
• In the preparation of citrate-stabilized ceria aqueous sol, which was employed in the synthesis of cerium oxide nanoparticles.
• In the preparation of phosphate citrate buffer for use in a study.
• To prepare citric acid-Na2HPO4-buffered stock solution for use in a study.
• To prepare anticoagulant citrate dextrose solution A (ACD-A).
• To synthesize palladium cuboctahedrons via oxidative etching by hydrogen chloride, which allows controlling of the particle size.

General description

Citric acid is an organic acid commonly used in food and pharmaceutical industries. It is employed in the synthesis of citric acid-derived carbon nanodots (CNDs) by bottom-up carbonization method. The phase diagram of citric acid-tartaric acid binary mixture shows eutectic behavior. The catalytic activity of citric acid for acetylation reaction of alcohols and phenols can be enhanced by immobilization on magnetic nanoparticles. Molar enthalpy of solution in water of its anhydrous and monohydrate forms have been reported. Citric acid participates as a bi-component chelating agent during the synthesis of Li4Ti5O12.

Legal Information

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Other Notes

Go to Redi-Dri Product Listing 791725

Price and Availability

Interactive Buffer Table

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Non-Sterile Millex Syringe Filters
Safety & Documentation

Safety Information

GHS07  GHS07
Signal word 
Hazard statements 
Precautionary statements 
Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 


Certificate of Analysis

Certificate of Origin

Protocols & Articles


Determination of Water Content in Citric acid anhydrous Using Karl Fischer Titration

Group(s): Carboxylic Acids, Cosmetic Products + Compounds, Pharmaceutical Products + Compounds
Keywords: Esterifications, Pharmaceutical, Titrations

MSMLS Online Plate Map

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Keywords: Mass spectrometry, Metabolites

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