Glove permeation tests using novel microchemical techniques for 2,4-dichlorophenoxyacetic acid (2,4-D) derivatives

The aim was to assess the permeation of different herbicide emulsion concen trate formulations of 2,4-dichlorophenoxyacetic acid (2,4-D) as 60.8 and 83 .5% butoxyethyl ester (BEE) and 46.8% dimethyl amine salt (DMAS) through fo ur types of glove materials (fined unsupported nitrile, unlined unsupported butyl, Silver Shield laminate, and Viton). This entailed the development o f new microchemical techniques to allow sensitive capillary gas chromatogra phy/mass spectrometry (GC/MS) of the permeated herbicide. The 2,4-D DMAS wa s esterified to the methyl ester by boron trifluoride-methanol complex with 99.2 +/- 3.7% efficiency using microwave heating to minimize reaction time and to process microsamples. The GC/MS detection limit was 5 ng/ml (ppb) o f 2,4-D DMAS in the collection medium. The permeates from the ester formula tions were analyzed directly for the ester above the detection limit of 9 n g/ml (ppb) BEE. The permeation investigations utilized the American Society for Testing Materials (ASTM)-type permeation cells with liquid collection media. The results showed that these gloves could provide at least 6 h prot ection for these formulations.