Construction of a dual-mode sensing platform for ANS-inserted CoCu-LDH composites and its high-performance detection of dopamine.

Dopamine (DA), a crucial neurotransmitter, demands precise monitoring due to its implications in neurological disorders. Current single-mode detection strategies often suffer from reliability issues. To address this, we engineered a novel hierarchical nanoarchitecture by co-intercalating the fluorescent molecule 1-naphthylamine-8-sulfonate (ANS) and the surfactant sodium 1-octanesulfonate (OS) into cobalt‑copper layered double hydroxide (CoCu-LDH), followed by exfoliation into colloidal nanosheets (OS0.2ANS0.8-LDH). This design ingeniously integrates dual detection modalities within a single material. The LDH host provides a confined environment that enhances and stabilizes the fluorescence of ANS, while the Co3+/Co2+ and Cu2+ redox couples create an efficient electrocatalytic center. For fluorescence detection, DA quenches the ANS emission via a synergistic mechanism involving dynamic quenching and an inner filter effect, achieving a high sensitivity with a limit of detection as low as 0.069 μM. For electrochemical detection, the composite-modified electrode exhibits excellent electrocatalytic activity toward DA oxidation with a wide linear range and achieves a low detection limit of 0.093 μM. The sensor demonstrates exceptional selectivity against common interferents and reliable performance in real tap water samples, where the recovery rates for DA were determined to be between 96.8% and 99.6%. This work presents not only a high-performance bifunctional sensing platform but also a generalizable material design strategy for constructing self-validating diagnostic devices.