Cyclam-Functionalized Silica-Modified Electrodes for Selective Determination of Cu(II)

Cyclam derivatives have been grafted via 1, 2 or 4 silylated arms to the surface of mesoporous silica and the resulting materials have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Cu(II). Sensitive and selective detection of the target analyte was achieved owing to the attractive binding properties of this macrocyclic ligand towards Cu(II) species. Various parameters likely to affect the preconcentration and detection steps have been studied, including pH of the accumulation medium, composition of the detection solution, structure and composition of the adsorbent, accumulation time, or presence of potentially interfering species. In particular, the effect of the number of silylated groups linking the macrocycle to the silica network on the sensor performance was discussed. After optimization, Cu(II) can be determined in a linear concentration range extending from 2 nM to 100 mu M. The method was validated by reliable Cu(II) determination in tap water.