On-line preconcentration with different solid adsorbents for lead determination

An on-line column preconcentration method based on the combined use of ammonium O,O-diethyldithiophosphate and activated carbon or polyurethane foam as adsorbents has been developed for the determination of Pb in water samples. The complexed Pb was eluted with ethanol and determined by flame atomic absorption spectrometry. The optimum preconcentration conditions are given for each adsorbent. The enrichment factors were 63 and 294, and the detection limits (3sigma) 3 microg L(-1) and 0.8 microg L(-1), respectively, for the carbon and foam systems. When the optimized procedures were applied to the determination of Pb in water samples the recovery efficiency was > 96%.