ANALYSIS OF PHENOXYALKYL ACID HERBICIDES AND CHLOROPHENOLS BY CAPILLARY ZONE ELECTROPHORESIS

A capillary zone electrophoresis system (CZE) with on-line UV detection was used for the determination of two phenoxyalkyl acid herbicides (2,4-D and 2,4,5-TP) and two chlorophenols (2,4-dichlorophenol and 2,4,5-trichlorophenol). Under an applied voltage of 23 kV, all compounds migrated towards the cathode within 10 min. Phosphate buffer was used and the separation of different species was achieved by combining electrophoretic and electro-osmotic effects. The coefficient of electro-osmotic flow and the electrophoretic mobilities of individual compounds were calculated. A linear relationship between peak area and sample amount was obtained in the range of 4-56 pg for 2,4-D, 2,4,5-TP and 2,4-dichlorophenol and of 10-46 pg for 2,4,5-trichlorophenol. The detection limit was lower than 6 pg. The coefficients of variation of peak area and retention time were 3.4-6.1% and 0.2%, respectively.