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 30031 EPA Method 525 - Internal Standard Price on request 2680.6-K-IO 2,3-Dimethylthiophene, 1000µg/mL, Solvent-isooctane, Unit 1mL, # of units-1, Cas.no. 632-16-6 Price on request 2676.8-100MG Tetrabromophthalic anhydride Price on request