Description

Ascorbic Acid
Vitamin C; L-Ascorbic Acid OH OH

H C6H8O6 Formula wt **6.*3 INS: **0 CAS: [******7]

DESCRIPTION

Ascorbic Acid occurs as white or slightly yellow crystals or as powder. It melts at about **0c It gradually darkens on exposure to light, is reasonably stable in air when dry, but rapidly deteriorates in solution in the presence of air. One gram is soluble in about 3 mL of water and in about *0 mL of alcohol. It is insoluble in chloroform and in ether.

Function Antioxidant; meat-curing aid; nutrient.

REQUIREMENTS

Identification

A. A 1:*0 aqueous solution slowly reduces alkaline cupric tartrate TS at *5c but more readily upon heating.

B. The infrared absorption spectrum of a potassium bromide dispersion of the sample exhibits maxima at the same wavelengths as those of a similar preparation of USP Ascorbic Acid Reference Standard.

Assay Not less than *9.0% and not more than **0.5% of C6H8O6.

Lead Not more than 2 mg/kg.

Optical (Specific) Rotation Between **0.5c nd **1.5c

Residue on Ignition Not more than 0.1%.

TESTS

Assay Dissolve about **0 mg of sample, accurately weighed, in a mixture of **0 mL of water, recently boiled and cooled, and *5 mL of 2 N sulfuric acid. Titrate the solution immediately with 0.1 N iodine, adding starch TS near the endpoint. Each milliliter of 0.1 N iodine is equivalent to 8.**6 mg of C6H8O6.

Lead Determine as directed in the Flame Atomic Absorption Spectrophotometric Method under Lead Limit Test, Appendix IIIB, using a **-g sample.

Optical (Specific) Rotation Determine as directed under Optical (Specific) Rotation, Appendix IIB, using a solution containing 1 g of sample in *0 mL of carbon dioxide-free water.

Residue on Ignition Determine as directed under Residue on Ignition, Appendix IIC, igniting a *-g sample.

Packaging and Storage Store in tight, light-resistant containers.