EPA Method 551.1 Internal Standard Back Catalog number: 32103 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 681604 Dihydroxy quinoxaline, 100mg Price on request 0944.19-K-IO 3-Methyloctadecane, 1000µg/mL, Solvent-isooctane, Unit 1mL, # of units-1, Cas.no. 6561-44-0 Price on request 93755 Isocratic Test Standard Price on request