Modern Chemistry & Applications

Abstract

Development of Liquid Chromatography Separation and a Solid-Phase Extraction Method for Phenoxy Alkanoic Acid Herbicides in Water

Bechir Hammami, Mohamed Bahri, Sihem Ben Hassine and Mohamed Ridha Driss

A sensitive solid phase extraction enhancement reversed-phase high-performance liquid chromatography (RPHPLC) determination was adopted for the separation and the determination of phenoxy alkanoic acids herbicides in water. The analytes that have been concentrated were eluted and separated on a C¹⁸ analytical column at a flow of 1 mL min^-1 and were determinate by measuring their UV absorption at 220 nm. A solid phase extraction (SPE) method was developed for the analysis of seven phenoxy alkanoic acid herbicides. The effects of the sample volume, sorbent mass and pH on the recoveries of these herbicides were investigated. Sample volume under to 1000 mL could be handled without any loss of analytes. The recoveries were dependent of sample pH in the range >80% and were achieved with pH=3 using 5 mL of methanol as desorption solvent. These acid herbicides were determined simultaneously using this method with good linearity (R²>0.998). The developed method SPE/RP-HPLCUV permitted the determination of phenoxy alkanoic aids in distilled water down to a level of 0.17 ng L^-1 showing satisfactory recovery (>85%) for 1 L samples. The developed method was evaluated by analysis of surface water spiked at 1 μg L^-1, so this method is suitable for detecting herbicide residues of sub-parts-per-billion levels in surface water.