Appearance Green brown to brown powder
PH 1.2(pink)~2.8(yellow)
7.4(brown-yellow)~9.0(purple)
Maximal absorbing waelength,nm
λ1(Ph1.2)
λ2(Ph2.8)
λ1(Ph7.4)
λ2(Ph9.0)
526~529
431~437
431~437
576~580
Quality absorption coefficient,L/cm.g
α1(λ1,Ph1.2, dry base)
α1(λ1,Ph2.8, dry base)
α1(λ1,Ph7.4, dry base)
α1(λ1,Ph9.0, dry base)
80~94
40~46
39~45
75~86
Ethanol solution testing Pass
Residue on iginition 0.25% max
Loss on drying 1.0% max