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C1909 Sigma-Aldrich

Citric acid monohydrate

ACS reagent, ≥99.0%

  • CAS Number 5949-29-1

  • Linear Formula HOC(COOH)(CH2COOH)2 · H2O

  • Molecular Weight 210.14

  •  Beilstein Registry Number 4018641

  •  EC Number 201-069-1

  •  MDL number MFCD00149972

  •  PubChem Substance ID 24892446



Related Categories Acids, Acids & Bases, Building Blocks, C6, Carbonyl Compounds,
grade   ACS reagent
assay   ≥99.0%
impurities   Substances carbonizable by hot sulfuric acid, passes test
  ≤0.005% Insoluble matter
ign. residue   ≤0.02%
pKa    (1) 3.13, (2) 4.76, (3) 6.4
solubility   H2O: soluble 54 % (w/w) at 10 °C (Citric acid in water)
  H2O: 59.2 % (w/w) at 20 °C (Citric acid in water)
  H2O: 84.0 % (w/w) at 100 °C (Citric acid in water)
anion traces   chloride (Cl-): ≤0.001%
  oxalate (C2O42-): passes test (limit about 0.05%)
  phosphate (PO43-): ≤0.001%
  sulfate (SO42-): ≤0.002%
cation traces   Fe: ≤3 ppm
  Pb: ≤2 ppm



1, 2.5 kg in poly bottle

12 kg in poly drum

25, 500 g in poly bottle


Citric acid monohydrate was used in the preparation of citric acid solution employed in the acetone method of 68Ga pre-purification and radiolabeling technique.
It may be used:
• As release-modifying agent to improve the release of diltiazem hydrochloride from melt extruded Eudragit RS PO tablets.
• To prepare citrate buffer for use in the preparation of platelets for intravital microscopy.
• To prepare Tris-citrate buffer employed for the electrophoresis of bacterial enzymes.

General description

Citric acid monohydrate is an organic acid. Its molar enthalpy of solution in water has been reported to be ΔsolHm (298.15K, m = 0.0203molkg-1) = (29061±123)Jmol-1. It can be produced by crystallization from mother liquor of citric acid solution at 20-25°C during citric acid synthesis. An investigation of its crystal growth kinetics indicates that growth is linearly dependent on size.

Safety & Documentation

Safety Information

GHS07  GHS07
Signal word 
Hazard statements 
Precautionary statements 
Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
343.4 °F
Flash Point(C) 
173 °C

LC-MS Grade Solvents and Reagents

Meet Synthia - Retrosynthesis Sofware
Protocols & Articles


A general protocol for the generation of Nanobodies for structural biology

Els Pardon a, b , Toon Laeremans a, b , Sarah Triest a, b , Søren G F Rasmussen c , Alexandre Wohlkönig a, b , Armin Ruf d , Serge Muyldermans b, e , Wim G J Hol f , Brian K Kobilka g , Jan Steyaert ...
Keywords: AGE, Adsorption, Amplification, Antibiotics, Biochemistry, Biotinylations, Buffers, Cancer, Centrifugation, Chromatography, Cloning, Coagulation, Crystallization, DNA purification, Deaminations, Degradations, Detergents, Digestions, Diseases, Drug discovery, Electrophoresis, Enzyme-linked immunosorbent assay, Flow cytometry, Gel electrophoresis, Gene expression, Genetic, Genomics, Hematology, High performance liquid chromatography, Immobilization, Immunology, Infectious Diseases, Neuroscience, Nucleic acid annealing, Nucleic acid hybridization, Peptide synthesis, Phase transitions, Polymerase chain reaction, Purification, Sample preparations, Separation, Sequencing, Size-exclusion chromatography, Sterilizations, Transfection, Western blot, transformation

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