Molecularly imprinted polymer-assisted SERS assay with electrokinetic preconcentration for detection of theophylline in tea beverage

Accurate detection of theophylline (THP) is often hindered by interference from structurally similar compounds and limitations in sensitivity. To address these challenges, this work introduces a novel voltage-assisted molecularly imprinted surface-enhanced Raman scattering (MIP-SERS) platform by integrating in-situ electrokinetic preconcentration with specific molecular recognition. The key innovation lies in applying an optimized potential during incubation to actively drive and accelerate THP binding kinetics at imprinted sites, thereby overcoming the intrinsic diffusion limitations of passive MIP sensors and improving the SERS intensity. As a result, the sensor achieves an exceptional detection limit of 0.52 nM, and a linear range of 1.0 × 10 −9 -1.0 × 10 −5  M, while demonstrating robust quantification in complex tea matrices. This platform has significant potential for precise therapeutic drug monitoring and food safety control, establishing a new paradigm for sensitive detection in complex samples.