... /Amino Acid, Appearance:White crystals or pale yellow crystalline powder L-Tryptophan/Feed Grade/Amino Acid,CAS NO: 73-22-3 ... ,Certificate of Analysis:ItemStandard(Q/AFF08-2008/ AJI92 )Test ResultAppearanceWhite crystals or pale yellow crystalline ... .5%0.14%Residue on ignition ≤0.5%0.10% L-Tryptophan, Feed Additive, Amino Acid