EPA Method 601 Internal Standard Back Catalog number: 19094 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 10900.17-K-DS Promethazine hydrochloride,1000 µg base/mL,DMSO,1mL Price on request 59979 Ammonia as (NH4+) Price on request 57224 Chromium (Cr) Price on request