EPA Method 515.1 Internal Standard Back Catalog number: 30023 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 679334 N-Ethyl-p-toluenesulfonamide, 250mg Price on request X9198 Thionazin Price on request 681819 2-Methyl-1,2-benzisothiazolin-3-one, 25mg Price on request