Citric acid monohydrate is an organic acid. 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.

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, or to prepare Tris-citrate buffer employed for the electrophoresis of bacterial enzymes.

• 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
• Grade: ACS reagent
• InChI Key: YASYEJJMZJALEJ-UHFFFAOYSA-N
• 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