Improved sensors based on composite materials for cadmium, lead and copper determination

Water is fundamental for all the Earth’s living forms, and a key issue for social and economic development. Some of the metals that can be found in water are: Cu, Cd and Pb and a high concentration of these metals can have consequences on human health.

Many carbon materials are well-known conductive material, widely used in the fabrication of composite electrodes. In this work, diverse allotropic forms of carbon as graphite, multiwalled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) were tested. Furthermore, these materials allow the construction of cheaper, smaller, portable, reliable, and easy to use devices, which can be easily modified by two routes, on surface or matrix. To use said composites electrodes for metal detection, Square Wave Anodic Stripping Voltammetry (SWASV) is the select technique, which consists in two steps. Fist, applying a potential to preconcentrate the analyte on the surface of the electrode and second the measurement is performed applying staircase potential and the current generated is recorded.

To increase the sensitivity of the composite sensor, it would be ideal to exploit the potential properties of mercury for metal detection by tuning electrode’s surface. Due to mercury’s hazardous properties and to reduce the amount used in polarography, the use of nanoparticles is a good option due to their properties. Mercury nanoparticles were used to modify the surface of the composite electrodes to improve electroanalytical sensor response.