color of DPPH reagent - (Oct/18/2007 )

this is my first time using DPPH reagent for free radical scaverging activity. after i dissolve in methanol, the color become brownish..is it correct? because all the literature state that the color of DPPH is violet/ purple in color. after react with antioxidant, it will become colorless/ yellow in color//

maybe it is too concentrated. how does it look when you dilute it?

hi..finally i check already. actually is the lab assitant give the wrong chemical, should be 1,1-diphenyl-2-picrylhydrazyl, but the lab provided 1,1-diphenyl-2-picrylhydrazine..

thank for giving help :-)