1-Propanesulfonic acid, 3-((3-hydroxy-4-((5-nitro-2-pyridinyl)azo)phenyl)propylamino)-, monosodium salt 113516-70-4 2-(5-Nitro-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol Nitro-paps