Abstract
For the selective determination of agrichemicals containing copper, “Oxine-copper”, in aqueous samples, a flow method based on the combination of on-line liquid-liquid extraction with a reversed micellar mediated chemiluminescence (CL) detection was established. The analyte, which contained bis(8-quinolinolato)copper(II) as a major component, was extracted into chloroform from an aqueous sample bufferd at pH 6.0, followed by membrane phase separation in the flow system. In a flow cell of a detector, the extract was mixed with a reversed micellar solution of cetyltrimethylammonium chloride in chloroform-cyclohexane (6 : 5 v/v)-water containing luminol. At the reversed micellar interface, the extracted copper(II) complex dissociated rapidly to produce copper(II) ion. The released copper(II) ion catalyzed the CL oxidation reaction of luminol. Using a reverse-flow injection system, a detection limit of 5.5 μg dm−3 and a linear calibration graph with a dynamic range of up to 1.1 mg dm−3 were obtained for oxine-copper under the optimized experimental conditions. The effect of interference that would be caused by co-existing chemical species was also described.
