EPA Method 8121 Surrogate Standard Back Catalog number: 81204 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 0977.27-10-IO d2 C27 alpha alpha alpha (20R)-Cholestane, 10µg/mL in Isooctane, 1ml Price on request 54533 Ammonium (NH4+) Price on request 673787 Diflufenican, 100 µg/ml, Ethyl acetate, 1ml Price on request