Molecular formula:  C₄H₆O₆

Molecular Weight:  150.1

Assay:  99.5%min

Melting Point:  164-170℃

Specific rotation (20℃):  -12 to -12.5^o

Residue on ignition:  0.1% max.

Oxalates:  0.35% max.

Sulfate:  0.2% max.

Heavy metal( as Pb)： 10ppm

As:  2ppm max