Metal-clad optical waveguide fluorescence device for the detection of heavy metal ions

摘要

We developed Hg~(2+)-sensing chips by decorating the external surface of metal-clad optical waveguides with a monolayer of Hg~(2+)-sensitive fluorescent molecular probes. The emission properties of the original water-soluble form of the molecule were previously found to be selectively quenched in the presence of Hg~(2+) ions. The fabricated samples were tested with optical waveguide fluorescence spectroscopy by putting them in contact with a 5-μM water solution of Hg~(2+) ions and recording the emission spectra versus incubation time. The estimate of the limit of detection was 150 nM. A preliminary evaluation of the selectivity of the structure was also performed by using Cd~(2+) as possible interfering analytes.