Computationally optimized molecularly imprinted electrochemical sensor based on biomass-derived biochar for...

Paclobutrazol (PBZ) is widely used in agriculture, but its residues in medicinal herbs may compromise product safety and quality. In this work, a molecularly imprinted electrochemical sensor was developed for the determination of PBZ in Radix Angelicae Sinensis. The sensor integrates Angelica stalk-derived biochar as a sustainable porous carbon substrate with a molecularly imprinted layer rationally designed through a combined computational approach. Density functional theory (DFT) calculations (Dmol3 module) were employed to screen the optimal functional monomer (o-phenylenediamine), and Forcite molecular dynamics simulations were further applied to determine the ideal template-to-monomer ratio, ensuring high-affinity recognition cavity formation. A deep eutectic solvent was introduced as a green eluent for template removal. Under optimized conditions, the MIP/ASB/GCE sensor exhibited a linear response from 50 to 450 nM, with an LOD of 11.49 nM and an LOQ of 38.30 nM. The sensor showed acceptable selectivity, reproducibility, repeatability, and storage stability.Recovery tests in spiked Radix Angelicae Sinensis samples gave recoveries of 105.80-109.30%. These results indicate that the proposed sensor is applicable for PBZ monitoring in complex herbal matrices and that the integration of biomass-derived carbon, molecular simulation-assisted imprinting, and green elution chemistry provides a useful strategy for MIP-based electrochemical sensing.