Method for the analysis of triadimefon and ethofumesate from dislodgeable foliar residues on turfgrass by solid-phase extraction and in-vial elution

Triadimefon, a fungicide, and ethofumesate, an herbicide, are commonly appl ied to turfgrass in the Pacific Northwest, resulting in foliar residues. A simple and rapid method was developed to determine triadimefon and ethofume sate concentrations from dislodgeable foliar residues on turfgrass. Turfgra ss samples were washed, and wash water containing surfactant (a 0.126% solu tion) was collected for residue analysis. This analytical method utilizes a 25 mm C-8 Empore disk and in-vial elution to quantitatively determine tria dimefon and ethofumesate in 170 mt aqueous samples. The analytes were elute d by placing the disk in a 2 mt autosampler vial with 980 mu L of ethyl ace tate and 20 mu L of 2-chlorolepidine, the internal standard, for analysis b y GC/MS. The method quantitation limits are 0.29 mu g/L for ethofumesate an d 0.59 mu g/L for triadimefon. The method detection limits are 0.047 mu g/L and 0.29 mu g/L for ethofumesate and triadimefon, respectively. Concentrat ions of triadimefon and ethofumesate from dislodgeable foliar residues from a field study are reported.