A FULLY AUTOMATED FLOW-INJECTION ATOMIC-ABSORPTION SYSTEM FOR THE DETERMINATION OF COPPER TRACES IN WATERS WITH ON LINE PRECONCENTRATION IN AN ION-EXCHANGE COLUMN

The paper describes the development of an automatic on-line column pre-concentration technique using a time based-flow injection atomic absorption spectrometry system. A manifold incorporating a micro-column containing 25 mg of Dowex 50 W-X8 was used with a time-based injector for the pre-concentration and determination of copper in natural and drinking waters. The system features depend on the alternate positions of a solenoid valve. The 3 sigma detection limits, enrichment factors, sampling frequency, relative standard deviations and linear calibration graphs mere, respectively, in the range 0 . 6-1 . 5 mu g/l, 25-60, 15-30 measurements/h, 1 . 0-3 . 1% and 1-65 mu g/ml for pre-concentration times of 1 min. The procedure was successfully applied to a range of water samples and the accuracy was assessed through recovery experiments, the analysis of certified reference water samples and by independent analysis by atomic absorption spectrometry with electrothermal atomization.