Simultaneous Electrochemical Determination of Polycyclic Aromatic Hydrocarbons Based on Layered Double Hydroxide-Derived Carbon/rGO@AgNPs Composite in Herbal Medicine

Polycyclic aromatic hydrocarbons (PAHs) are high-risk, persistent organic pollutants that exhibit carcinogenic, teratogenic, and mutagenic effects. These compounds readily form and accumulate during cultivation, processing, and storage of herbal medicines. Therefore, it is significant for enhancing the quality control of herbal medicine by developing effective determination methods. In this study, a composite material was synthesized based on layered double hydroxide-derived carbon (LDC) and silver nanoparticle-doped reduced graphene oxide (rGO@AgNPs). The composite has been successfully applied in the simultaneous electrochemical sensing of benzo-[a]-pyrene (BaP) and phenanthrene (PHE). The morphological and structural properties of the material were characterized by using field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) techniques. The LDC-rGO@AgNP-based sensor demonstrated exceptional performance in 0.1 M Mg-(ClO₄)₂/acetonitrile aqueous solution, exhibiting wide linear ranges (2-256 μM for both analytes), low detection limits (0.72 μM for BaP and 0.82 μM for PHE), significant anti-interference capability against common interferents, along with good reproducibility and stability. The practical applicability of this sensor was demonstrated through the standard addition method in Coptis chinensis samples, thereby establishing an electrochemical sensing platform for robust monitoring of PAH contaminants in herbal medicines.