Double-amplified photoelectrochemical response of hematin on carbon nanohorns superstructure support for ultrasensitive detection of roxarsone

A new proposal for designing sensitive photoeletrochemical sensor with a ternary hybrid film developed by absorbing hematin on carbon nanohorns superstructures and poly-l-lysine complex support to achieve quantificational detection of 4-hydrox-3-nitrobenzenenearsonic acid (HNBAA) was offered. Here, hematin with easy acquirement, good biocompatibility and strong visible light harvesting capability, was introduced as photosensitizer for photoelectrochemical determination. Additionally, the complex support composed by fascicled superstructures of carbon nanohorns which possessed many superiors, such as excellent electronic conductivity, large specific area and adsorption etc., and poly-l-lysine which could form hydrogen bond with hematin performed excellent immobilization action of hematin. Due to the synergistic effect and surface enhancement effect, complex support provided a charge-transfer matrix to catch and transport excited electron from hematin rapidly, which was benefit to baffle photogenerated electron-hole recombination and improve photoelectrochemical signal in visible light region effectively. HNBAA, as a photogenerated hole scavenger, enhanced the photoelectrochemical response again. Furthermore, the excellent sensitivity and broad linear detection range to HNBAA of this sensor with good stability and high selectivity, satisfied reproducibility and acceptable accuracy was propitious to practical application of sample analysis, and the good biocompatibility of modified materials and low applied potential on this sensor laid a foundation for its promising application.