Ascorbic acid (vitamin C)

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ITEM	STANDARD
Appearance	White or almost white crystal or crystalline powder
Identification	Positive
Melting point	191 ℃ ~ 192℃
pH (5%, w/v)	2.2 ~ 2.5
pH (2%,w/v)	2.4 ~ 2.8
Specific optical rotation	+20.5° ~ +21.5°
Clarity of solution	Clear
Heavy metals	≤0.0003%
Assay (as C 6H 8O6, %)	99.0 ~ 100.5
Copper	≤3 mg/kg
Iron	≤2 mg/kg
Mercury	≤1 mg/kg
Arsenic	≤2 mg/kg
Lead	≤2 mg/kg
Oxalic acid	≤0.2%
Loss on drying	≤0.1%
Sulphated ash	≤ 0.1%
Residual solvents (as methanol)	≤ 500 mg/kg
Total plate count (cfu/g)	≤ 1000
Yeasts & molds (cfu/g)	≤ 100
Escherichia. Coli/g	Absence
Salmonella/ 25g	Absence
Staphylococcus aureus/ 25g	Absence