EPA Method 8021B Internal Standard Back Catalog number: 19394 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 0940.14-500-IO 3,4-Dimethyldiphenylsulfide, 500µg/mL, Solvent-isooctane, Unit 1mL, # of units-1, Cas.no. 2828-65-1 Price on request 674844 Piperonyl butoxide, 100mg Price on request 677805 Caproic acid, 1ml Price on request