A robust and inexpensive aqueous mercury sensor based on a gold nanoparticle film is described. The film is contained within an exposure chamber which allows for the optimization of the mercury mass transfer. The sensor detects mercury down to ng L−1 concentrations with a linear response. The response to mercury in field and lab-created samples with high levels of other inorganic species is consistent, suggesting that the sensor is selective. The sensor requires no mercury preconcentration or inert gas and is straightforward to operate.
