EPA Method 8121 Internal Standard Back Catalog number: 81203 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 676691 Heptachlor, 100 µg/ml, Ethyl acetate, 1ml Price on request 71256 3,5-Dichlorophenol Price on request 32495 Dichloroacetonitrile Price on request