On-line preconcentration with different solid adsorbents for lead determination

An on-line column preconcentration method based on the combined use of ammo nium O,O-diethyldithiophosphate and activated carbon or polyurethane foam a s adsorbents has been developed for the determination of Pb in water sample s. The complexed Pb was eluted with ethanol and determined by flame atomic absorption spectrometry, The optimum preconcentration conditions an given f or each adsorbent. The enrichment factors were 63 and 294, and the detectio n limits (3 sigma) 3 mu gL(-1) and 0.8 mug L-1, respectively, for the carbo n and foam systems. When the optimized procedures were applied to the deter mination of Pb in water samples the recovery efficiency was > 96%.