S P E C I F I C A T I O N S

PURPURIN

Synonyms:			1,2,4-Trihydroxy-9,10-anthracenedione
				C.I. No.: 58205

CAS No.:				81-54-9

Chemical Formula:			C14H8O5 

Formula Weight:			256.22

Appearance:				Dark-red to orange-brown to brown powder

Assay (HPLC):			Min. 94%

Impurity HPLC:			Max 3% Alizarin

Loss on drying:			Max 1%
(150˚ C 1 hour)

Melting Point:			253 °C to 256 °C 

Spectrophotometric Assay		E (237nm +/- 3nm) = 17000
Conc. 0.01g/l in methanol		E (257nm +/- 3nm) = 17000
Extinction Co-efficient		E (514nm +/- 3nm) =   7000

pH: 					3.8 to 4.5
(50mg in 100 m/l, 50/50			
THF & H2O)

Manganese (Mn) ICP:		Max. 500ppm
Sulfur (S) ICP:			Max. 1500ppm

Solubility:				Red to very dark red to purple solution
 (1mg/ml NH4OH)

Effective Date: 0712/11