Sodium Acid Pyrophosphate (SAPP): CAS No.: 5578-16-9 Molecular Formula: Na2H2P2O7 Item Value Unit Index Content (as counted by Na2H2P2O7) 95 % Min Water Insoluble 1.0 % Max PH (1% aqueous solution) ±4.0 Arsenic(As), 3 ppm Max Heavy Metals (as Pb), 20 ppm Max Fluoride(F), 50 ppm Max