SELECTIVE DETERMINATION OF PHENOLS IN WATER BY A 2-TRAP TANDEM EXTRACTION SYSTEM FOLLOWED BY LIQUID-CHROMATOGRAPHY

The ability of a two-trap tandem system, one containing 300 mg of grap hitized carbon black (GCB) and the other filled with 50 mg of Sephadex QAE A-25 strong anion exchanger (SAX), to extract trace amounts of ph enols from environmental waters and isolate them from base-neutral spe cies was evaluated. After the water sample had passed through the GCB cartridge, the latter was connected to the SAX cartridge and base-neut ral species were removed from the GCB surface by a neutral eluent. Co- eluted very weakly acidic phenols were selectively readsorbed on the S AX surface. Still maintaining the two cartridges in series, an acidifi ed eluent was allowed to flow through the two cartridges to recover th e most acidic phenols from the GCB cartridge and the least acidic phen ols from the SAX cartridge. After partial removal of the solvent, the final extract was submitted to reversed-phase high-performance liquid chromatography with UV detection. Recoveries of seventeen phenols of e nvironmental concern added to 21 of drinking water at levels between 0 .2 and 2 mug/l were higher than 90%. The effect of the presence in wat er of fulvic acids on the efficiency of the extraction device was asse ssed. In term of recovery, the two-trap tandem system was compared wit h other two single extraction cartridges, one containing a chemically bonded siliceous material (C18) and the other SAX material. The limits of detection of the analytes considered were well below 0.1 mug/l.