Propyl paraben USP/NF Propylparaben is widely used as an antimicrobial preservative in cosmetics, food products, and pharmaceutical formulations. USPâ??NF is a combination of two compendia, the United States Pharmacopeia (USP) and the National Formulary (NF). Sales Specification Appearance: White Crystalline Powder Assay: 98.0% â?? 102.0% IR Identification: Positive Melting Point: 96oC â?? 99oC Color of Solution: Clear Residue on Ignition: 0.1% Max Organic Impurities: 0.5% Max Total Impurities: 1.0% Max Residual Solvents: n-Propanol 3000 PPM Max Packing 55.12 LB bag/ 20 bags per pallet