Chapter 8: Dispersible Electrodes: An Approach to Developing Sensing Devices that can Quickly Detect Ultralow Concentrations of Analyte

This chapter presents the ‘dispersible electrodes’ concept, a novel electrochemical detection system to detect ultra-trace levels of analyte in large samples in a reasonable time frame. In this concept instead of the analyte finding the sensor by diffusion or convection, the sensor finds the analyte. Basically, the electrochemical sensor is subdivided into tiny pieces by using conducting gold coated magnetic nanoparticles (Au@MNPs) as active element in the selective capture and direct electroanalytical quantification of the species of interest. The Au@MNPs are dispersed in solution; once the capturing process has completed, a magnetic field is applied and brings the nanoparticles to the sensing interface to carry out the electrochemical measurements. The chapter covers from the synthetic approach of the Au@MNPs to the surface functionalization of the particles, electrochemical characterization, applications, and performance of the dispersible electrodes.