FIELD COMPARISON OF POLYURETHANE FOAM PLUGS AND MINI-TUBES CONTAINING TENAX-TA RESIN AS TRAPPING MEDIA FOR THE AERODYNAMIC GRADIENT MEASUREMENT OF TRIFLURALIN VAPOR FLUXES

The effectiveness of a low-volume (0.31 min(-1)) mini-tube (MT) sampler packed with Tenax-TA resin was compared in a field study with that of a polyurethane foam (PUF) sampler (25 1 min(-1)) for measurement of herbicide vapour concentrations in air following fall soil-incorporation of trifluralin at 690 g ha(-1) Based on a paired comparison, no significant difference was observed in trifluralin concentrations (ng m(-3)) determined by gas chromatographic (GC) analysis of air samples collected using the MT and PUF samplers. As a consequence, fluxes determined using the aerodynamic gradient method of measurement for either sampler type were also similar. Because the entire air sample collected by the MT sampler was transferred onto the GC column, greater sensitivity was achieved using the MT sampler.