Upconversion nanoparticles incorporated with three-dimensional graphene composites for electrochemical sensing of baicalin from natural plants†

Chinese medicine has been widely studied owing to its many advantages. Baicalin (Bn), extracted from natural plants, has been shown to have significant anti-inflammatory and anticancer activity. Therefore, it is of great significance to develop a suitable method to detect the content of Bn in traditional Chinese medicine. Herein, we report an electrochemical sensor for the sensitive detection of Bn in Scutellaria root samples through a synergistic effect between upconversion nanoparticles (UCNPs) and three-dimensional macroporous graphene (3DG). The prepared UCNP-3DG composite was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (XRD). This proposed sensor exhibited a low detection limit of 3.8 × 10⁻⁸ M (S/N = 3). Importantly, the established method possesses good stability and selectivity and can successfully detect Bn in Scutellaria root samples. It provides a suitable strategy for the determination of Bn and has potential application prospects in the assay of traditional Chinese medicine.