Evaluation of silica gel and XAD‐4 as adsorbents for herbicides in air

Abstract

Abstract Silica gel and XAD‐4 resin were shown to be efficient solid adsorbents for sampling vapors of ii‐butyl and iso‐octyl esters of (2,4‐dichlorophenoxy)acetic acid (2,4‐D), ii‐butyl ester of (2,4,5‐trichlorophenoxy)acetic acid (2,4,5‐T), octanoate ester of 3,5‐dibromo‐4‐hydroxybenzonitrile (bromoxynil) , S (2,3,3‐trichloroa‐llyl)diisopropylthiocarbamate (triallate), and α,α,α‐trifluoro‐2, 6‐dinitro‐N, N‐dipropyl‐p‐toluidine (trifluralin) herbicides in ambient air. The adsorbed herbicides were readily extracted by shaking the adsorbent with methanol or by Soxhlet extraction with a 1:1 mixture of acetone and n‐hexane and subsequently analyzed with electron‐capture GLC. The overall efficiencies of the two adsorbents, for both trapping and ease of extraction, were in the 85 to 100% range.