Study on the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chloro-phenoxyacetic sodium (MCPA sodium) in natural agriculture-soils of Fuzhou, China using capillary electrophoresis.

A new method of analyzing trace 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2-methy-4-chloro-lphenoxyacetic sodium (MCPA sodium) in soils by capillary electrophoresis (CE) has been developed in this study. The optimum analytical conditions including chemical component and concentration of buffer solution, pH, separation voltage and sample injection time were studied in detail. Under the optimum conditions, 2,4-D and MCPA sodium in soils can be speedy separated and determined within 20 min with detection limits of 0.15 microg/g (2,4-D) and 0.25 microg/g (MCPA sodium) , a RSD (n=6)<5% and a recovery>89%. With the help of analytical method developed in this study, the degradations of 2,4-D and MCPA sodium in natural agriculture-soils of Fuzhou were studied. The experimental results indicated that the degradations of 2,4-D and MCPA sodium follow first-order kinetics with degradation constants of 0.1509 day(-1) (2,4-D) and 0.2722 day(-1) (MCPA sodium) respectively. The degradation half-life were calculated to be 4.6 days (2,4-D) and 2.6 days (MCPA sodium) at 27 degrees C, implied that 2,4-D and MCPA sodium can be speedy degraded in natural agriculture-soils of Fuzhou, China.