Lijun Yan

A portable electrochemical sensor was developed using a screen-printed electrode modified by graphdiyne carbon dots and black phosphorene (GCDs@BP) nanocomposite, with the EmStat3 Blue potentiostat enabling real-time data acquisition and Bluetooth transmission to a smartphone for 7-hydroxycoumarin (7-HC) detection. The GCDs@BP nanocomposite was synthesized via a green self-assembly approach using aqueous-phase processing. Electrochemical determination of 7-HC using the GCDs@BP/SPE sensor demonstrated high sensitivity, a broad linear detection range (0.2–1000 µM), and a low detection limit of 51.3 nM. The synergistic enhancements in sensing performance are attributed to: (1) the formation of interfacial P–C and P–O–C bonds, as confirmed by XPS, which facilitates efficient charge transfer and enhance electrocatalytic activity, (2) the uniform dispersion of GCDs within the BP matrix, revealed by HRTEM and Q-t curves, which increases the effective surface area and provides abundant adsorption sites for 7-HC; and (3) the suppression of phosphorus atomic vibrations, evidenced by Raman peak redshift, indicating strong interfacial coupling that improves structural stability. The proposed sensor was successfully applied to the determination of 7-HC in traditional Chinese medicines, including Zu Shi Ma and Shu Gan He Wei pills, with satisfactory recovery and reproducibility. Graphical Abstract

Black phosphorene quantum dots (BPQDs) were prepared by ultrasonic-assisted liquid-phase exfoliation and centrifugation with morphologies proved by TEM results. Furthermore, an electrochemical enzyme sensor was prepared by co-modification of BPQDs with horseradish peroxidase (HRP) on the surface of a carbon ionic liquid electrode (CILE) for the first time. The direct electrochemical behavior of HRP was studied with a pair of well-shaped voltammetric peaks that appeared, indicating that the existence of BPQDs was beneficial to accelerate the electron transfer rate between HRP and the electrode surface. This was due to the excellent properties of BPQDs, such as small particle size, high interfacial reaction activity, fast conductivity, and good biocompatibility. The presence of BPQDs on the electrode surface provided a fast channel for direct electron transfer of HRP. Therefore, the constructed electrochemical HRP biosensor was firstly used to investigate the electrocatalytic behavior of trichloroacetic acid (TCA) and potassium bromate (KBrO₃), and the wide linear detection ranges of TCA and KBrO₃ were 4.0–600.0 mmol/L and 2.0–57.0 mmol/L, respectively. The modified electrode was applied to the actual samples detection with satisfactory results.

In this work, a novel portable and wireless intelligent electrochemical nanosensor was developed for the detection of 6,7-dihydroxycoumarin (6,7-DHC) using a modified screen-printed electrode (SPE). Black phosphorene (BP) nanosheets were prepared via exfoliation of black phosphorus nanoplates. The BP nanosheets were then mixed with nano-diamond (ND) to prepare ND@BP nanocomposites using the self-assembly method, achieving high environmental stability. The nanocomposite was characterized by SEM, TEM, Raman, XPS and XRD. The nanocomposite was used for the modification of SPE to improve its electrochemical performances. The nanosensor displayed a wide linear range of 0.01–450.0 μmol/L with a low detection limit of 0.003 μmol/L for 6,7-DHC analysis. The portable and wireless intelligent electrochemical nanosensor was applied to detect 6,7-DHC in real drug samples by the standard addition method with satisfactory recoveries, which extends the application of BP-based nanocomposite for electroanalysis.