Determination of fluoride by an ion chromatography system using the preconcentration on nanometer-size zirconia

A simple rapid microcolumn preconcentration technique is described for the determination of fluoride ions in geological samples through the ion chromatography system. The technique is based on the adsorption of fluoride ions on H2SO4-activated nanometer-size zirconia (NSZ) packed in a microcolumn. Activation parameters (concentration and contact time) were studied, and an activation time of about 50 min and a concentration of 6 M were then selected. The analytical procedure was optimized in terms of the flow rate of the sample solution, eluent concentration, and the eluent flow rate for the adsorption capacities of H2SO4-activated NSZ. At a flow rate of 1.0 mL/min, the detection limits (3 sigma) of the technique for fluoride ions was 0.3 ng/mL, and the RSD was 0.04%. The dynamic adsorption capacity of NSZ was found to be 8.4 mg/g.