EPA Method 551.1 Internal Standard Back Catalog number: 32103 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended 679451 Ametryn, 100 µg/ml, Methanol, 1ml Price on request 10376.21-100MG DL-Methadone-d9 hydrochloride Price on request 679699 Arprinocid, 10mg Price on request