Detección electroquímica de peróxido de hidrógeno usando peroxidasa de pasto Guinea (Panicum maximum) inmovilizada sobre electrodos serigrafiados de puntos cuánticos

摘要

Electrochemical biosensors are analytical tools of fast and reliable response that have acquired interest in the last years due to the possibility of integrating biomolecules and electrodes made of nanometric materials. In this study, an electrochemical biosensor to detect hydrogen peroxide (H2O2) based on Guinea Grass peroxidase (GGP) immobilized on screen-printed quantum dots electrodes (SPQDE) was developed. GGP was partially purified from Guinea grass leaves having a specific activity of 602 U mg-1.Then, GGP was immobilized by physical adsorption on the surface on SPQDE and the electrochemical behavior was carried out through cyclic voltammetry and chronoamperometry techniques. GGP revealed a well-defined pair of redox signals at 17mV/-141mV corresponding to the redox process of the heme group (Fe2+/Fe3+) of peroxidases. The bioelectrocatalytic reduction of H2O2 has a redox potential of -645 mV vs Ag. This process was controlled by the diffusion of the species on the electrode surface using a scan rate range of 50-500 mV s. Chronoamperometry studies allow us the construction of calibration curves of reduction current vs H2O2 concentration for the determination of analytical parameters such as sensitivity, linear range and minimum detection level. The development of this amperometric biosensor becomes a preliminary step for the construction of a portable and rapid response device for the analysis of H2O2 in samples of environmental and biomedical interest.