Gas chromatographic-mass spectrometric method for the analysis of dimethomorph fungicide in dried hops

An analytical method for the determination of dimethomorph [(E,Z)-4-[3-(4-c hlorophenyl)-3-(3,4-dimethoxyphenyl)acryloyl] morpholine] residues in dried hops was developed utilizing liquid-liquid partitioning, automated gel per meation chromatography (GPC), Florisil and aminopropyl solid phase extracti on (SPE) column cleanups, and gas chromatography (GC) with mass selective d etection (MSD). Method validation recoveries from dried hops ranged from 79 to 103% over four levels of fortification (0.1, 1.0, 5.0, and 20 ppm). Con trol and dimethomorph-treated hop samples collected from three field sites had residue levels of <0.10 and 4.06-17.32 ppm, respectively. The method wa s validated to the limit of quantitation at 0.10 ppm. The limit of detectio n for this method was 0.045 ppm.