EPA Method 551.1 Surrogate Standard Back Catalog number: 31102 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 681811 Pyriofenone, 100 µg/ml, Acetonitrile, 1ml Price on request 673029 Atenolol, 100mg Price on request 673758 Chlorbromuron, 10.0 µg/ml, Ethyl acetate, 10ml Price on request