Fiber optic based evanescent wave sensor for the detection of elemental mercury utilizing gold nanorods

We developed a fiber optic based sensor using gold nanorods as the sensing medium for the detection of atmospheric elemental mercury. Mercury readily adsorbs on the nanoparticles causing a measurable shift in the longitudinal localized surface plasmon resonance. Depositing the nanorods on the surface of a bare, bent fiber optic cable provides a means to excite the resonance and determine the absorbance through the evanescent wave at the surface. The response of the system is linear with concentration, and we have been able to directly measure concentrations down to 1.0 μg/m3.