13C3-Caffeine, 100 µg/ml, Methanol, 1ml Back Catalog number: 681491 Manufacturer: HPC STANDARDS GmbH Availability: In the manufacturer's stock Price on request - + Recommended 31102 EPA Method 551.1 Surrogate Standard Price on request 70954 Azinphos methyl, 1000µg/ml in MeOH, 1ml Price on request 678465 Paraoxon-methyl, 100mg Price on request