Picomolar detection of mercuric ions by means of gold-silver core-shell nanorods

We report an ultrasensitive and selective probe for detection of mercuric ions using gold-silver core-shell nanorods as the substrate of surface-enhanced Raman scattering. The detection limit of this probe for mercuric ions can be as low as 1 pM. The efficiency of this probe in complex samples was evaluated by allowing detection of spiked mercuric ions in river water and fish samples.