Application of an Astragalus biochar molecularly imprinted electrochemical sensor for highly sensitive sensing and...

In this study, a novel electrochemical sensing interface was developed for the detection of triazophos (TAP) in tea. Notably, a deep eutectic solvent (DES) was innovatively employed as the template eluting solvent for molecularly imprinted polymers (MIPs). Compared with common template eluting solvents, DES, composed of choline chloride and urea, yielded excellent elution effects. Diphenyl phosphoryl chloride (DCP) was employed as the dummy template molecule, and methacrylic acid (MAA) served as the functional monomer. Subsequently, the obtained MIPs combined with Astragalus biochar were deposited on a glassy carbon electrode (GCE) via the layer-by-layer self-assembly method to improve the performance of electrical sensors. The electrochemical behavior of the MIP/BC@GCE was assessed via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The sensor exhibited outstanding sensitivity and selectivity towards TAP, with a broad linear range from 1.0 × 10^-12 to 1.0 × 10^-8 M, a low detection limit of 3.3 × 10^-13 M, and a recovery rate ranging from 85.0% to 99.1%, demonstrating reliable reproducibility and stability. The transformation of plant waste into biochar for utilization in composite electrode-based sensing may hold a broad application prospect for trace analysis.