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.