Photoelectrochemical Sensor Employing the Two-Dimensional Donor–Acceptor PPDA–NiPc COF for Sensitive Analysis of Curcumin

Curcumin is extensively utilized across various domains including the food, pharmaceuticals, and chemical industries. However, excessive curcumin intake may induce tissue necrosis, thereby posing a substantial threat to human health, making rapid and precise detection of curcumin levels paramount. Here, tetranitro nickel phthalocyanine (NiPc) was synthesized via a solid-phase method. Subsequently, it underwent an azo condensation reaction with p-phenylenediamine (PPDA) under the assistance with potassium hydroxide. This process was used to fabricate a nickel phthalocyanine-based covalent organic framework material (PPDA-NiPc COF). Herein, NiPc serves as the acceptor unit (A) with high electron-accepting capability, while PPDA functions as the donor unit (D) to provide electrons. The D-A architecture established through imine bond formation, which significantly enhances photogenerated charge carrier separation and transfer. The photoelectrochemical sensor constructed based on two-dimensional COF exhibits remarkable sensitivity for curcumin detection. It demonstrates a favorable linear response within the concentration range of 0.05 to 50 μM, with a detection limit as low as 1.46 nM. Moreover, this detector possesses superior stability and reproducibility and enables accurate quantification curcumin in real samples. This study not only expands COF material applications in photoelectrochemical sensing but also provides a novel strategy for detecting curcumin.