Colorimetric discrimination of chrysanthemum polyphenols via tunable MOF-818 nanozyme sensor array

Chrysanthemum is an important botanical resource with medicinal and dietary value, whose quality and therapeutic efficacy are closely related to its polyphenolic composition. However, conventional polyphenol analysis is limited by high cost, time consumption, and operational complexity. To address these challenges, a colorimetric sensor array was constructed using two metal-organic framework nanozymes (MOF-818-1 and MOF-818-2). Although derived from identical precursors, modulated solvothermal synthesis endowed the nanozymes with distinct catecholase-like catalytic activities, enabling the oxidation of o-diphenols into colored o-quinones. Differential responses toward chlorogenic acid (CGA), quercetin (QR), and dicaffeoylquinic acid (DCQA) generated characteristic two-dimensional fingerprints. Combined with multivariate pattern recognition methods, including principal component analysis (PCA), linear discriminant analysis (LDA), partial least squares discriminant analysis (PLS-DA), and hierarchical cluster analysis (HCA), the sensor array enabled proof-of-concept discrimination and concentration estimation of target polyphenols. The method was successfully applied to real chrysanthemum extracts, providing a rapid, simple, cost-effective strategy for herbal quality control.