To verify the influence of the loading and elution flow rates on the recovery of all investigated analyte ions at optimum values of all variables, a set of similar preconcentration experiments were carried out employing different flow rates. It was observed that the extraction is independent of the loading flow rates in the range of 1–4 mL min1 for loading sample and 1.0 mL min1 for eluent indicating very rapid sorption kinetics. A flow rate of 4 mL min1 was used.