An ultra-sensitive photoelectrochemical biosensing platform based on the AgVO3/BiOI heterojunction for an enzyme activity inhibition reaction

An ultra-sensitive photoelectrochemical sensing platform for profenofos detection based on the inhibition of catalase activity was prepared in this work. First, the novel functional nanocomposite material AgVO3/BiOI was prepared by a hot solvent method and successive ion layer adsorption reaction. Then, chitosan was employed as a dispersion medium to disperse and immobilize the catalase. Under visible light irradiation, the prepared CAT/CS/AgVO3/BiOI/ITO nanocomposite electrode generates a stable low photocurrent in hydrogen peroxide solution. When this electrode is immersed in a phosphate buffer solution containing profenofos, the activity of the catalase is inhibited, resulting in an increase in the photocurrent. Under the optimized experimental conditions, the profenofos concentration and increase in photocurrent are linearly related in the concentration range of 1 × 10−10 to 5.0 × 10−8 mol L−1, and the limit of detection is 1.0 × 10−11 mol L−1. This biosensor shows good selectivity for detecting profenofos in fruits and vegetables, and the determination results of profenofos are satisfactory.