The effect of temperature upon the electrochemical stripping performance of a heavy metal sensor based on carbon nanoparticles is studied. The morphological changes of the sensing surface during the multidetection of Cd²⁺, Pb²⁺, Cu²⁺ and Hg²⁺ ions are studied by TEM and SEM. The effect of the temperature on the heavy metal deposition using carbon nanoparticle-based SPEs is also compared to a sensor that does not contain carbon nanoparticles. The effect of temperature seems to be more pronounced for the nanoparticle-based sensor. This phenomenon is clarified by the electrochemical response as well as the TEM and SEM images of the sensing materials used. In addition, the response performance of the nanoparticle-based sensors for increasing concentrations of heavy metals from 5–100 μg L⁻¹ for Cd²⁺, Pb²⁺ and Cu²⁺ and from 1 to 10 μg L⁻¹ for Hg²⁺, in both single and multiple detections with potential for real applications, is presented. The nanoparticle-based sensor seems to be stable for up to one month while being used in continuous monitoring of heavy metals in seawater.

We report a novel and efficient method for the laser direct writing of two-dimensional silver structures. Multiphoton absorption of a small fraction of the output of a Ti:sapphire oscillator is sufficient to photoreduce silver nitrate in a thin film of polyvinylpyrrolidone that has been spin-coated on a substrate. The polymer can then be washed away, leaving a pattern consisting of highly interconnected silver nanoparticles. We report the characterization of the silver patterns using scanning electron and atomic force microscopies, and demonstrate the application of this technique in the creation of diffraction gratings.