FORENSIC CHEMICAL STUDY ON 2,4-DICHLOROPHENOXY ACETATE (PHENOXY HERBICIDE) BY GAS-CHROMATOGRAPHY

Accidental and suicidal poisonings with sodium 2,4-dichlorophenoxy acetate (2,4-D-Na) have occurred occasionally in the fields of forensic toxicology. The gas chromatographic method for the determination of 2,4-D-Na involving the preparation of the n-propyl ester was studied. 2,4-D-Na was directly converted with n-propanol-boron-trifluoride to the n-propyl ester which was measured by gas chromatography, although the esterifications so far have been carried out after being led to its free acid. Sep-pak C18 cartridge was applied to the simple and rapid extraction of 2,4-D-Na from the urine in the following matter, a urine sample was adjusted to pH 7.0, poured into a Sep-pak C18 cartridge, 2 ml of H2O-methanol (75:25, v/v) was put into the cartridge to selectively eliminate urinary components and finally 2 ml of H2O-methanol (20:80, v/v) was poured into the cartridge to elute 2,4-D-Na, at a constant rate of flow, 5 ml/min. 2,4-D-Na was satisfactorily recovered and no interference was observed for gas chromatography after esterification. This method is more efficient, simple, and less time-consuming than previous described methods.