On-line preconcentration and determination of trace metals using a flow injection system coupled to ion chromatography

A flow injection (FI) method with on-line preconcentration using a mini-column loaded with 8-hydroxyquinoline immobilized on controlled pore glass (CPG-8HQ) is described for the determination of trace metals by ion chromatography (IC) with pyridine-2-6-dicarboxylic acid (PDCA) as the eluent. Copper, cadmium, lead, zinc, nickel and iron were determined at ppb level after post-column derivatization with 4-(2-pyridylazo)-resorcinol (PAR). The detection limits (3σ) for the FI/IC system were 8.27, 0.89, 0.09, 0.06, 0.09 and 0.07 g l−1 for Pb2+, Cd2+, Cu2+ Ni2+, Zn2+ and Fe3+, respectively, using 5 ml sample volume. The method was applied to the analysis of Malaysian natural waters.