Determination of Phenoxy Acid Herbicides in Drinking Waters by HPLC and Solid Phase Extraction

Abstract

An HPLC procedure for determining phenoxy acid herbicides in waters is described. A LichroSpher RP select B octadecyl-silane analytical column and spectrophotometric detection at 230 nm were used. Adequate retention was achieved with a mobile phase containing MeOH/phosphate buffer 10⁻² M pH 2.5/PnOH (50/42/8, v/v). The herbicides were isolated from water samples by using a single solid phase extraction procedure with C₁₈ solid-phase columns. An enrichment factor of 500 is achieved. The coefficients of variation of the method were generally lower than 2.7% at 0.4 μg L⁻¹ herbicide concentration levels. Recoveries ranged between 93 and 118%. The results obtained indicate that the proposed method is well suitable for monitoring phenoxy acid herbicides in compliance with the European Community standard for drinking water.