Derivative-synchronous fluorescence spectroscopy enhanced surface plasmon coupled emission for sensitive detection of tannic acid

Abstract

In this study, we developed a new derivative-synchronous fluorescence spectroscopy enhanced surface plasmon coupled emission (DS-SPCE) technique for the detection of tannic acid (TA). DS-SPCE generates greatly amplified directional fluorescence signal, approaching nearly a 20-fold enhancement. The property of a gradual fluorescence quenching of the monolayer Rhodamine B isothiocyanate (RBITC) with increasing TA concentration was used for the quantitative detection of TA. The method achieved an ultra-low limit of detection (LOD) of 15.3 pM. It exhibited high selectivity for TA detection, even in the presence of common interferences such as glucose, catechin, and ascorbic acid at concentrations exceeding 100-fold. DS-SPCE method demonstrated robust performance in analyzing TA in tea samples, yielding good average recoveries of TA. Consequently, DS-SPCE emerges as a straightforward fluorescence enhancement approach, providing valuable insights for its practical application.