PENTACHLOROPHENOL PRECONCENTRATION USING QUINOLIN-8-OL IMMOBILIZED ON CONTROLLED-PORE GLASS AND FLOW SPECTROPHOTOMETRIC DETERMINATION

A pentachlorophenol preconcentration method using a microcolumn (20 x 2.5 mm i.d.) filled with quinolin-8-ol (oxine) immobilized on controlled-pore glass (CPG) is proposed. The method is based on retention at pH 1 and elution at pH 3 with acetonitrile-water (80 + 20). Maximum retention of pentachlorophenol was 180 mug per gram of oxine-CPG. The breakthrough volume was 100 ml. The good ability for retention and elution allows the flow spectrophotometric determination of microgram amounts of pentachlorophenol. The calibration graph was linear from 4.0 to 25 mug for a sample volume of 100 ml, the repeatability using a single column for 12 mug of pentachlorophenol was 1.2% (R.S.D., n = 4), and the reproducibility between five different microcolumns for the same concentration level was 1.6%. The 3sigma detection limit was 2.5 mug and a preconcentration factor of 250-fold was obtained. Common cations and other phenols do not interfere significantly.