Vitamin C powder (Ascorbic Acid) VC

Vitamin C powder (Ascorbic Acid)
 

Ascorbic Acid
Vitamin C; L-Ascorbic Acid OH OH
H C6H8O6 Formula wt 176.13 INS: 300 CAS: [50-81-7]

DESCRIPTION
Ascorbic Acid occurs as white or slightly yellow crystals or as powder. It melts at about 190 C, 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 30 mL of alcohol. It is insoluble in chloroform and in ether.
Function Antioxidant; Meat-curing aid; Nutrient.

REQUIREMENTS
Identification
A. A 1: 50 aqueous solution slowly reduces alkaline cupric tartrate TS at 25 C 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 99.0% and not more than 100.5% of C6H8O6.
Lead Not more than 2 mg/kg.
Optical (Specific) Rotation D25: Between +20.5and +21.5.
Residue on Ignition Not more than 0.1%.

TESTS
Assay Dissolve about 400 mg of sample, accurately weighed, in a mixture of 100 mL of water, recently boiled and cooled, and 25 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 8.806 mg of C6H8O6.
Lead Determine as directed in the Flame Atomic Absorption Spectrophotometric Method under Lead Limit Test, Appendix IIIB, using a 10-g sample.
Optical (Specific) Rotation Determine as directed under Optical (Specific) Rotation, Appendix IIB, using a solution containing 1 g of sample in 10 mL of carbon dioxide-free water.
Residue on Ignition Determine as directed under Residue on Ignition, Appendix IIC, igniting a 2-g sample.
Packaging and Storage Store in tight, light-resistant containers