Abstract
In this study a new hopeful enrichment/separation technique to substitute for batch and column techniques is described. Lead and cadmium were selected as analyte elements. The housing of a syringe mountable membrane filter was filled with Purolite C-100 E cationic resin and mounted to the tip of a plastic syringe. If the sample solution was drawn into the syringe in about 30 s passing through the resin and discharged again for the same length of time, the analyte elements were quantitatively retained at pH ≥ 2. The elements sorbed by the resin were then quantitatively eluted by drawing and discharging 2.5 M HCl as eluent, again at the same flow rates as those used in retention. The recoveries of Pb and Cd were 98.2 and 99%, respectively, with relative standard deviations of around ± 2%. Detection limits (3δ) were 15 µgL−1 for Pb and 10 µgL−1 for Cd. The elements could be concentrated by drawing and discharging several portions of sample successively but eluting only once. Pb and Cd in spiked waste water were recovered quantitatively (>95) with low RSD values of around ±2%. The method proposed is cheaper, simpler, faster and more practical than the column technique. The recoveries and reproducibilities of the method are at the same level as those of the column technique.