Gold nanorod-based mercury sensor using functionalized glass substrates

We report on the development of a gold nanorod-based mercury sensor, immobilizing these anisotropic metal nanoparticles on glass substrates. This novel approach is expected to find applications in the measurement of mercury traces in stream-flow. We present first a “modified” wet chemistry procedure to functionalize glass surfaces with gold nanorods, which confer control on the density of particles on the glass substrate. Then, we demonstrate that this mercury sensor, using immobilized gold nanorods on glass substrates, retains the outstanding selectivity of our previously reported mercury sensor using suspended gold nanorods, presents an extraordinary sensitivity and, does not require any sample separation and/or sample pre-concentration. The analytical figures of merit demonstrate precise and accurate analysis at the parts-per-billion level, figures with great potential for monitoring low levels of mercury in flowing water. The entire procedure in solution takes less than 60 s.