Name :METHOD 23 ALTERNATE RECOVERY STOCK SOLUTION Isotope :(13C12, 99%) Catalog Number :EDF-5189 Quantity: 1.2 ML Formula :no formula is available. Categories: Dioxin & Furan Mixtures (DFM), US EPA Method Mixtures (E) 1,2,3,7,8,9-HexaCDF (13C12,99%) .