Nanomaterial decorated electrodes in flow-through electrochemical sensing of environmental pollutants: A critical review

The current state-of-the-art of nanomaterial-based electrochemical sensors in flow injection (NBES-FI) platforms for in-line determination of environmental pollutants (since 2013 to mid-2023) is herein critically reviewed. The synergistic effects of FI platforms and nanomaterial-based modifiers, such as metal nanoparticles and carbon-based nanomaterials, for minimizing electrode fouling, alleviating overpotential, and boosting the overall figures of merit are discussed in detail. The role of experimental parameters including (i) the electrode nature, shape, design and configuration, (ii) the synthetic routes of (nano)materials, and (iii) the electrochemical detection technique on the analytical performance of NBES-FI is thoroughly evaluated. Current challenges and needs for real-world exploitation of NBES-FI in environmental settings are outlined along with perspectives for the integration of NBES-FI with microextraction approaches and the exploitation of 3D printing technology for fabrication of customized fluidic platforms.