A novel water-soluble sulfonated porphyrin fluorescence sensor for sensitive assays of H2O2 and glucose

Abstract

Water soluble porphyrins have many perfect analytical figures of merit. A water-soluble sulfonated porphyrin (H₂TEHPPS) was used to build a novel platform for sensitive assays of hydrogen peroxide and glucose based on the different effects of Fe²⁺ and Fe³⁺ on H₂TEHPPS. H₂O₂ or Fe²⁺ alone cannot induce a fluorescence change in H₂TEHPPS, but Fe³⁺ can quench the fluorescence of H₂TEHPPS significantly. Interestingly, glucose is oxidized to gluconolactone by GOD and generates an equivalent hydrogen peroxide, and the produced H₂O₂ also oxidizes Fe²⁺ to Fe³⁺ and causes the fluorescence quenching of H₂TEHPPS. According to this, a sensitive sensor for hydrogen peroxide and glucose has been demonstrated, which can determine H₂O₂ and glucose in a relative simple and sensitive way. The detection limits were 1.3 × 10⁻⁷ M and 3.2 × 10⁻⁷ M for H₂O₂ and glucose, respectively. In addition, the glucose in serum samples was determined successfully using this sensing platform. It is also noteworthy that H₂O₂ can be released in almost all oxidations catalyzed by oxidases, which suggests that this newly proposed H₂O₂ probe can be readily extended to sense other oxidases and their specific substrates.