.alpha.,.alpha.'-Diphenyl-.beta.-picrylhydrazyl .alpha.,.alpha.-Diphenyl-.beta.-picrylhydrazyl 1,1-Diphenyl-2-picrylhydrazyl 1898-66-4 2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl 2,2-Diphenyl-1-picrylhydrazyl DPPH Diphenylpicrylhydrazyl Diphenylpicrylhydrazyl free radical Hydrazyl, 2,2-diphenyl-1-(2,4,6-trinitrophenyl)- Hydrazyl, 2,2-diphenyl-1-picryl- N,N-Diphenyl-N'-picrylhydrazyl NSC12562