Detection of copper with potentiostatically controlled microcantilever sensors

Atomic force microscopy microcantilevers coated with gold were used as the working electrode to monitor the deposition and stripping processes of copper for different concentrations of Cu ²⁺ in a 0. 1 M NaNO ₃ supporting electrolyte (pH = 4.0). These processes, combined with electrochemical polarization techniques, caused microcantilever bending by changing the surface stress of the microcantilever electrode. Under these conditions, measurements of microcantilever surface stress shows high sensitivity for the detection of trace amounts (down to 10 ^-11 M) of Cu ²⁺. Anodic stripping of the copper shows a peak in the first derivative of surface stress with respect to potential. The potential of the peak allows the copper to be identified. This potential-controlled method offers the promise of achieving chemical selectivity for microcantilever sensor applications in liquid environments for a variety of analytes while still maintaining high sensitivity.