An enhanced photo-electrochemical sensor constructed from pillar [5]arene functionalized Au NPs for ultrasensitive detection of caffeic acid

Pillar [5]arene, a new water-soluble carboxylatopillar [5]arene ammonium salts (WP5), has been employed as the host for complexation of guest molecules. Herein, a visible light driven WP5 functionalized gold nanoparticles (Au@WP5) was fabricated for ultrasensitive photelectrochemical (PEC) detection of caffeic acid (CA). The ultraviolet–visible spectrum characteristics, PEC response results of samples in caffeic acid solution confirm the localized surface plasmon resonance effect of Au NPs and the host-guest interaction between WP5 and CA are responsible for the enhanced PEC sensing performance. Under optimal conditions, the sensitive PEC sensor constructed with Au@WP5 exhibited the concentration linear range from 0.025 μM to 370 μM and a detection limit of 0.01 μM (S/N = 3). Importantly, the good anti-interference ability, stability and reproducibility of the proposed PEC sensor providing the promising detection application of pillar [5]arene functionalized photoactive materials in food and drinks.