Coordination and π-π Stacking-Driven Conjugated Polymer Sensor Array for Polyphenol Fingerprinting and Tea...

The characterization of complex natural mixtures remains an analytical challenge due to the lack of specific biomarkers and the structural similarity of constituents. Herein, we report a multidimensional fluorescent sensor array based on anionic poly(p-phenylene ethynylene) (PPE) derivatives and their corresponding metal complexes for the high-fidelity authentication of tea cultivars. Unlike conventional cross-reactive arrays, our platform utilizes a rationally designed dual-mechanism response framework that synergistically integrates universal π-π stacking and selective competitive coordination between metal ions and polyphenolic motifs. Spectroscopic investigations, characterized by distinct bathochromic shifts and emission broadening, confirm that polyphenol-induced polymer aggregation serves as the ubiquitous underlying process, while metal-ion displacement provides a secondary, selective modulation layer. This synergistic interplay creates an information-rich response landscape, enabling the hierarchical discrimination of 20 commercial tea varieties across four fermentation categories with 100% classification accuracy. Furthermore, the array successfully resolves subtle subvarietal differences, including geographical origin and aging duration. By bridging the gap between nonspecific pattern recognition and mechanistic coordination chemistry, this work provides a robust and cost-effective strategy for the sophisticated analysis of complex natural matrices based on high-resolution polyphenol fingerprinting.