EPA Method 515.1 Internal Standard Back Catalog number: 30023 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 684867 D6-Sulfadimethoxine, 100 µg/ml, Acetonitrile, 1m Price on request 94179 Semi-Volatile Standard Price on request 2638.29-1UG 17 alpha(H),21ß(H)-25-Norhopane, 1µg Price on request