EPA Method 525 Internals & Surrogates Back Catalog number: 91161 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 2539.8-100MG 4-Hydroxyisophthalic acid (4-Hydroxybenzene-1,3-dicarboxylic acid), neat, Solvent-neat, Unit 100mg, # of units-1, Cas.no. 636-46-4 Price on request 59298 Ferrous Iron Level 3 Price on request 71332 2-Methylhexane Price on request