Iron single-atom nanozyme-enabled dual-mode electrochemical and colorimetric sensing for ultrasensitive detection of chlorogenic acid

Synthesized Fe–KAC single-atom nanozyme on KOH-activated ZIF-8-derived porous carbon via cascade anchoring. • Developed a dual-readout CGA assay combining complementary electrochemical and colorimetric signals. • Quantified CGA in honeysuckle from five regions, with 97.20%–106.1% recoveries (n = 5) and HPLC agreement. • Enabled routine quality assessment and origin-related quality screening of honeysuckle products. As a major phenolic constituent and a key quality marker of honeysuckle ( Lonicera japonica ), chlorogenic acid (CGA) requires rapid and reliable quantification to support routine quality control of honeysuckle-derived products. Herein, we developed a portable dual-mode sensing platform with colorimetric and electrochemical readouts enabled by a single-atom iron nanozyme (Fe–KAC). Fe–KAC was synthesized via a cascade anchoring strategy on a KOH-activated MOF-derived carbon support, featuring atomically dispersed Fe sites and high surface area, which jointly impart laccase-like catalytic activity and favorable electrochemical properties. The platform enabled CGA determination over linear ranges of 0.04–100.0 μM (electrochemical) and 3.00 μM–2.0 mM (colorimetric), with limits of detection of 0.0072 μM and 0.81 μM, respectively. The electrochemical method demonstrateed good selectivity and stability, and its accuracy was validated by comparison with HPLC as well as spike-recovery tests in honeysuckle products collected from five geographical origins, yielding recoveries of 97.2% to 106.1% ( n  = 5). Overall, this work presented a Fe-KAC-based complementary dual-readout sensing strategy for CGA detection, combining rapid colorimetric screening with sensitive electrochemical quantification, and showed potential applicability for the quality assessment of honeysuckle-derived products. Download: Download high-res image (107KB) Download: Download full-size image