EPA Method 500 Series Internal Standard Back Catalog number: 31004 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 0690.29-100-IO 28-Norlupane (17ß(H)/17 alpha(H)), 100µg/mL, Solvent-isooctane, Unit 1mL, # of units-1, Cas.no. 134501-93-2 / 134623-57-7 Price on request 681625 DL-Menthol, 250mg Price on request 1844.14-1G 4-n-Heptylbenzoic acid, neat, Solvent-neat, Unit 1g, # of units-1, Cas.no. 38350-87-7 Price on request