EPA Method 500 Series Internal Std #4 Back Catalog number: 32003 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 93010 Stearic acid butyl ester Price on request 72254 Sorbic acid Price on request 66149 2,2',3,4',5',6-Hexachlorobiphenyl (149) Price on request