Extraction of four herbicides from passive organic vapor monitors

Four herbicides (2,4‐D, MCPA, trifluralin, and triallate) were applied to and extracted from 3M #3500 Organic Vapor Monitors that use an activated charcoal pad as an adsorbent. Carbon disulfide (2 mL) with the addition of diazomethane in ethyl ether (1 mL) as the extracting liquid gave the best recovery results for all four pesticides. Average recovery efficiencies were 94% for trifluralin, 99% for triallate, 92% for 2,4‐D and 99% for MCPA. Extraction of the herbicides from the OVMs, using ethyl acetate, dichloromethane, methanol and acetone was also tested. All but acetone worked as well as CS2 to extract trifluralin and triallate, but none of the other solvents, even when combined with diazomethane, were as efficient as CS2 at desorbing 2,4‐D and MCPA.