Chitosan resin functionalized with 3,4-dihydroxy benzoic acid moiety (CCTS-DHBA resin) was used as a packing material for flow injection (FI) on-line mini-column preconcentration in combination with inductively coupled plasma-atomic emission spectrometry (ICP-AES) detection for the determination of trace elements, such as silver, bismuth, copper, gallium, indium, molybdenum, nickel, uranium, and vanadium in environmental waters. In this system, a 5-mL aliquot of sample (pH 5.5) was introduced to the minicolumn for the adsorption/preconcentration of the metal ions, and the collected analytes on the mini-column was eluted with 2 M HNO 3 , and the eluates was subsequently transported via direct injection to the nebulizer of ICP-AES for quantification. The parameters affecting on the sensitivity, such as sample pH, sample flow rate, eluent concentration, and eluent flow rate, were carefully examined. Alkali and alkaline earth metal ions commonly existing in river water and seawater did not affect on the analysis of metals in the present method. Under the optimum conditions, the proposed method allowed the determination of metal ions with the detection limits of 0.08 ng mL -1 (Ag), 0.9 ng mL -1 (Bi), 0.07 ng mL -1 (Cu), 0.9 ng mL -1 (Ga), 0.9 ng mL -1 (In), 0.08 ng mL -1 (Mo), 0.09 ng mL -1 (Ni), 0.9 ng mL -1 (U), and 0.08 ng mL -1 (V). By using 5 ml of sample solution, the enrichment factor and collection efficiency were found in the range of 8-12 fold and 96-102 %, respectively, whereas the sample throughput was 7 samples/ hour. The proposed method was validated by determining metal ions in standard reference materials of river water (SLRS-4) and nearshore seawater (CASS-4), and its applicability was further demonstrated to river water and seawater samples.
