Residue determination of glyphosate in environmental water samples with high-performance liquid chromatography and UV detection after derivatization with 4-chloro-3,5-dinitrobenzotrifluoride.

A pre-column derivatization high-performance liquid chromatographic method for glyphosate analysis has been developed. Derivatization of glyphosate was performed with 4-chloro-3,5-dinitrobenzotrifluoride (CNBF). In pH 9.5 H(3)BO(3)-Na(2)B(4)O(7) media, the reaction of glyphosate with CNBF completed at 60 degrees C for 30min. The labeled glyphosate was separated on a Kromasil C18 column (250mmx4.6mm, 5microm) at room temperature and UV detection was applied at 360nm. The separation of labeled glyphosate was achieved within 15min by gradient elution mode. Compared to other pre-column derivatization, this derivatization was performed more mildly, the derivative was more stable, and the detection limits of a few reagents were higher than CNBF, except 9-fluorenylmethyl chloroformate (FMOC-Cl) using fluorescence and mass spectrometry, however, this reagent avoid to be removed after derivatization like FMOC-Cl. The detection limit of glyphosate was 0.009mgL(-1) (S/N=3) without preconcentration and reach MRL, which is set at the level of 0.1mgL(-1) in China. The method linearity correlation coefficient was 0.9999, in concentrations ranging from 0.3 to 48.5mgL(-1). The proposed method has been applied to the quantitative determination of glyphosate in environmental water with recoveries of 91.80-100.20% and R.S.D. of 2.27-6.80, depending on the sample investigated.