EPA Method 500 Series Internal Std #4 Back Catalog number: 32003 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 9811.15-10MG 4-Acetylpsilocin fumarate, neat, Solvent-neat, Unit 10mg, # of units-1, Cas.no. Price on request 58123 Vanadium (V) Price on request 10030.3-K-ME 2-Chloro-1,3-propanediol, 1000µg/mL, Solvent-methanol, Unit 1mL, # of units-1, Cas.no. 497-04-1 Price on request