[Simultaneous determination of triazine herbicide residues in maize by gas chromatography]

A gas chromatographic method was developed for the determination of simeton, simazine, atrazine, propazine, terbumeton, terbuthylazine, cyprazine, simetryn, prometryn, terbutryn, methoprotryne, hexazinone residues in maize. The triazine herbicide residues were extracted with acetonitrile by blender and then cleaned up on a strong cation-exchange (SCX) solid-phase extraction cartridge. The SCX cartridge was conditioned with acetone, methylene chloride, washed with methylene chloride, acetone and eluted with methanol-water (9: 1, v/v) solution saturated potassium chloride. As a result, most interfering impurities were removed in the SPE cleanup procedure. The gas chromatographic analysis was performed on a capillary column (DB-5, 30 m x 0.25 mm i. d. x 0.25 microm) and determined by nitrogen phosphorus detector (NPD). Twelve triazine herbicides were effectively separated on this column. Diazinon was used as the internal standard for the determination. Linear correlation coefficients of the 12 herbicides were higher than 0.998 in the range of 0.01 to 2.0 mg/L. The limits of quantitation of the method were 0.01 mg/kg for these compounds. Average recoveries of these herbicides from spiked samples ranged from 84.0% to 106.8% at fortification levels of 0.01 - 0.5 mg/kg and the relative standard deviations (RSDs) were between 0.9% and 4.7%. The method is suitable for the simultaneous determination of a wide range of triazine herbicides in maize in commodities inspection.