C4H6O4 118.09
Butanedioic acid [110-15-6].

Identification— Place a drop of a saturated solution of the sample in a micro test tube,and add a drop of ammonium chloride solution (0.5in 100)and several mg of zinc powder.Cover the mouth of the tube with a disk of filter paper moistened with a solution in hexane containingp-dimethylaminobenzaldehyde (5in 100)and trichloroacetic acid (20in 100).Heat with a small flame for about 1minute:a pink to red-violet stain appears on the paper.

Melting range á741ñ: between 185.0and 190.0.

Residue on ignition á281ñ: not more than 0.025%.

Heavy metals,Method Iá231ñ: 0.002%.

Assay— Dissolve about 250mg,accurately weighed,in 25mLof carbon dioxide-free water.Add 2drops of phenolphthalein TSand titrate with 0.1Nsodium hydroxide VSto the production of a permanent pink color.Each mLof 0.1Nsodium hydroxide is equivalent to 5.905mg of C4H6O4.NF23

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 3093

Phone Number:1-301-816-8379