Detection of [Hg.sup.2+] using microcantilever sensors

Trace amounts of [Hg.sup.2+] are detected by using a microcantilever coated with gold. The microcantilever undergoes bending due to accumulation of [Hg.sup.2+] on the gold surface. It is found that a concentration of [10.sup.-11] M [Hg.sup.2+] can be detected using this technology. Other cations, such as [K.sup.+], [Na.sup.+], [Pb.sup.2+], [Zn.sup.2+], [Ni.sup.2+], [Cd.sup.2+], [Cu.sup.2+], and [Ca.sup.2+] have little or no effect on the deflection of the cantilever. The selectivity of the [Hg.sup.2+] sensor could be improved by coating the gold surface of microcantilever with a self-assembled monolayer of a long-chain thiol compound.