Electrochemical sensors for detecting bioactive constituents and contaminants in traditional Chinese medicines: research progress and critical perspectives.

Traditional Chinese medicines (TCMs) require analytical methods that can handle chemically complex matrices while addressing both efficacy-oriented constituent analysis and safety-oriented contaminant monitoring. Electrochemical sensors have attracted growing interest in this area because they offer low-cost instrumentation, short analysis time, and compatibility with portable formats, but their practical value depends on more than nominal sensitivity. This critical review evaluates recent progress in electrochemical sensing of bioactive constituents and contaminants in TCM-related matrices, with an emphasis on analytical performance, matrix adaptability, and real-sample validation. Representative constituent studies include simultaneous determination of baicalin and baicalein over 0.01-400 µM, with explicitly paired detection limits of 0.056 nM for baicalein and 0.49 nM for baicalin, and recoveries of 93.65-101.52%, as well as portable chlorogenic acid sensing with a 6.2 nM detection limit in herbal materials. Representative contaminant studies include glyphosate monitoring in TCM samples with an 8.8 × 10-10 M detection limit and 94.47-112.23% recoveries, Hg2+ sensing in Sanqi with an electrochemiluminescence detection limit of 0.27 pM, and ochratoxin A detection in medicinal-edible malt with a detection limit of 0.08 ng mL-1. Across the literature, molecularly imprinted polymers, nanocomposite interfaces, paper-based devices, and dual-mode transduction strategies have all shown analytical promise. However, matrix validation, comparator-method benchmarking, pretreatment transparency, and reproducibility reporting remain far less consistent than detection-limit reporting. The field is therefore most likely to advance not through ever-lower LODs alone, but through more standardized, application-oriented electrochemical methods for authentic TCM matrices.