Electrochemical Sensors Based on Functionalized Nanoporous Silica
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Nanostructured materials allow the development of miniature sensing devices that are compact, low-cost, low-energy-consuming, and easily integrated into field-deployable units. This article reviews our recent successful development of electrochemical sensors that are solid-state and mercury-free by using nanostructured materials. Specifically, thiol- or acetamide phosphonic acid-functionalized nanoporous silica materials have been incorporated in carbon paste electrodes for the detection of uranium, and the simultaneous detection of lead/mercury, and copper/lead/cadmium. Thiol-functionalized mesoporous silica thin film has been immobilized on gold electrode arrays for the detection of lead ions. The electrochemical sensors based on functionalized nanoporous silica yield reproducible measurements with excellent detection limits (at a few ppb of metal ions) and require little or no regeneration of electrode materials. Other advantages of our approaches, compared to those of current sensor technology, will also be discussed.