Metal-free miniaturized flexible electrochemical sensors based on nitrogen-doped carbon black for liquid crystal monomer detection

Abstract

Flexible electrochemical sensors offer a promising route for environmental monitoring; however, their deployment for on-site analysis is often constrained by limited response speed and poor portability. This study reports a miniaturized, portable detection system based on a flexible electrochemical sensor modified with non-metallic nitrogen-doped carbon black (N-CB) for the field detection of liquid crystal monomers (LCMs), an emerging class of aquatic pollutants. The system integrated a flexible microsensor with a compact wireless module, enabling rapid signal acquisition upon sample introduction and real-time data transmission to a smartphone for immediate analysis. The sensor demonstrated high accuracy, with recoveries ranging from 97.25% to 102.83%, and achieved a low detection limit of 0.13 µM. It further exhibited excellent operational stability and reproducibility across independently fabricated devices. This field-deployable and environmentally benign platform enables in situ pollutant monitoring, advancing analytical capabilities from centralized laboratories to point-of-need settings. More broadly, this approach enhances monitoring network resilience and supports sustainable water quality surveillance.