Wireless portable electrochemical sensor based on graphdiyne carbon dots and black phosphorene nanocomposite modified...

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.