Ion-pairing mechanism in the solid-phase extraction and reversed-phase high-performance liquid chromatographic determination of acidic herbicides in water

An alternative approach to the preconcentration of acidic herbicides from water and their HPLC determination utilizing an ion-pairing mechanism was developed. Triethylamine was applied as an ion-pairing reagent for increasing the retention of dicamba, bentazone, benazolin, 2,4-D and MCPA on C-18-bonded silica at neutral pH. Optimum conditions were found for solid-phase extraction in order to increase the recovery of analytes. Appropriate adjustments of the ion-pairing reagent and organic modifier in the mobile phase were made to optimize the HPLC retention and separation. An accurate and sufficiently sensitive analytical procedure was developed for the determination of the acidic herbicides in drinking and groundwater samples.