Dual-Mode Electrochemical and SERS Detection of Cadmium Ions in Water Using Laser-Induced Graphene Electrodes

High Resolution Image Download MS PowerPoint Slide Laser-induced graphene (LIG) provides a simple and low-cost approach for fabricating high-performance electrodes, offering an effective solution to the ongoing challenges of detecting heavy metal ions. We present a dual-mode sensing approach for cadmium ions (Cd 2+ ) based on LIG electrodes patterned on a commercial polyimide (PI) film. This platform integrates electrochemical and surface-enhanced Raman spectroscopy (SERS) sensing modes, enabling the complementary detection of Cd 2+ signals. For electrochemical measurements, square-wave anodic stripping voltammetry (SWASV) was employed, achieving a detection range of 0.045–1 μM and a limit of detection (LOD) of 40 nM. The effects of pH, deposition time, stirring speed, and applied potential on the electrochemical response were systematically investigated to optimize the performance of SWASV. For SERS sensing, LIG electrodes were modified with plasmonic silver nanoparticles (AgNPs), onto which trithiocyanuric acid (TTCA) probes were anchored. This functionalization enabled selective interaction of probes with Cd 2+, inducing changes in the SERS spectral features. This mode exhibited a broad detection range of 0.01–10 μM and a low LOD of 1.2 nM. The electrodes also showed excellent selectivity for Cd 2+ over common interfering ions such as Hg 2+, Cu 2+, Fe 2+, Mn 2+, and Zn 2+ . This work highlights the potential of LIG-based bimodal sensors for accurately monitoring heavy metals in environmental applications.