Signal-Inversion Strategy-Mediated Dual-Wavelength Ratiometric ECL Sensing for Sensitive Detection of 5F-ADB

The introduction of an efficient signal intensity flip device to construct a dual-wavelength ratiometric electrochemiluminescence (ECL) system is of great significance for the trace detection of target analytes. In this work, a dual-wavelength ratiometric ECL sensor was rationally designed using Zr-MOF as a bidirectional modulation factor, enabling complete reversal of the dual ECL signals at two distinct wavelengths and achieving highly sensitive detection of 5F-ADB. Specifically, Zr-MOF acts as a coreaction promoter to accelerate the decomposition of K₂S₂O₈, thereby significantly enhancing the cathodic ECL signal of Tg-CNNSs/CaMoO₄ at 475 nm. In addition, the overlap between the ultraviolet absorption and ECL emission spectra, along with the shortened fluorescence lifetime, confirms that Zr-MOF induces electrochemiluminescence resonance energy transfer (ECL-RET) in Eu-MOFs, resulting in pronounced quenching of the anodic ECL signal at 650 nm. The constructed sensor exhibited outstanding analytical performance, achieving a detection limit as low as 4.06 × 10^-15 g/L through the introduction of a highly complementary dual-aptamer recognition system. Furthermore, satisfactory recovery results in e-cigarette samples demonstrate the practical applicability and reliability of this sensing strategy, providing a new direction for the development of high-performance biosensors and drug-monitoring devices.