Ultrasensitive detection of arsenic in water using laser-scribed graphene-based electrodes

Arsenic contamination in water poses a serious health risk due to its high toxicity, even at ppb levels. In this work, we report a cost-effective graphene-based sensor with ultralow detection capabilities for arsenic. This is achieved by enhancing the catalytic efficiency of graphene electrodes through sunlight-assisted photothermal oxidation of a metal salt into metal oxide nanoparticles. The sensor demonstrated high sensitivity (34.81 ± 1.74 μA cm^-2 ppb^-1) and an ultralow detection limit (LOD 0.0636 ppb). Field tests on water samples from arsenic-contaminated zones in West Bengal, India, showed results consistent with the state-of-the-art ICP-OES analysis, highlighting the sensor's potential for practical, on-site arsenic monitoring.