Capillary gas chromatographic determination of terbutryn and its degradation products in sorghum grain and confirmation of the compounds by mass spectrometry.

An analytical method with a limit of detection 0.05 mg kg-1 is described for the determination of the herbicide terbutryn and its three degradation products, GS-26575, GS-11355 and GS-26831 in sorghum grains using fused silica capillary gas chromatography. Electron impact and methane chemical ionization mass spectra are reported to confirm the characterization of the compounds. No residues of these chemicals were found in sorghum harvested 14 weeks following terbutryn treatment at 0-4.5 kg ha-1.