EPA Method 507 - Internal Standard Back Catalog number: 19031 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 9397.20-K-ME Citalopram hydrobromide, 1000µg/mL, Solvent-methanol, Unit 1mL, # of units-1, Cas.no. 59729-32-7 Price on request 677316 Prochloraz Metabolite BTS44596, 10mg Price on request 2700.8-K-ME Isocaffeine (1,3,9-Trimethylxanthine), 1000µg/mL, Solvent-methanol, Unit 1mL, # of units-1, Cas.no. 519-32-4 Price on request