DETERMINATION OF PHENOXY ACID HERBICIDES IN DRINKING WATERS BY HPLC AND SOLID-PHASE EXTRACTION

An HPLC procedure for determining phenoxy acid herbicides in waters is described. A LichroSpher RP select B octadecyl-silane analytical colu mn and spectrophotometric detection at 230 nm were used. Adequate rete ntion was achieved with a mobile phase containing MeOH/phosphate buffe r 10(-2) M pH 2.5/PnOH (50/42/8, v/v). The herbicides were isolated fr om water samples by using a single solid phase extraction procedure wi th C-18 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 mu g 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 comp liance with the European Community standard for drinking water.