Development of electrochemical sensors for hydrogen peroxide determination
- Autores: Marta Borràs Brull
- Directores de la Tesis: Jordi Riu Rusell (dir. tes.), Pascal Blondeau (codir. tes.)
- Lectura: En la Universitat Rovira i Virgili ( España ) en 2020
- Idioma: inglés
- Tribunal Calificador de la Tesis: Francesc Xavier Rius Ferrus (presid.), María Isabel Pividori (secret.), Olivier Henry (voc.)
- Programa de doctorado: Programa de Doctorado en Nanociencia, Materiales e Ingeniería Química por la Universidad Rovira i Virgili
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Hydrogen peroxide (H2O2) is a simple molecule with important roles in many different fields. For instance, in the food industry H2O2 has been used as sterilizing compound in packaging and food manufacturing due to its antimicrobial and fungicidal properties and biological degradability. It is also used to rate the quality and safety of cosmetic and pharmaceutical formulations. Hydrogen peroxide is also used in paper products and textiles bleaching, providing a high degree of brightness and preserving the mechanical properties of the fibers. In metallurgical processes, H2O2 is used for ore leaching in order to save eluents and acids application and to simplify the management of chemical and waste. Since it is an oxidizing agent, its use in the chemical synthesis of flame retardants, catechol or herbicide production, among others, has also been reported for industrial purposes. We can also find hydrogen peroxide acting as oxidizing agent on waste water treatment, soil remediation or in air pollution control.
It is considered an important analyte in clinical diagnostics due to its implication in several routes of aerobic metabolism, in which its level can be used as a biomarker of some metabolic disorders related to the oxidative stress (e.g. asthma, osteoporosis or cardiovascular disorders, among others). It is also involved in some cellular signal transduction, mediating some physiological responses such as cell proliferation, differentiation and migration. Within the clinical field, it is also important due to its nature as a side product generated from biochemical reactions catalyzed by enzymes, such as glucose oxidase, cholesterol oxidase, glutamate oxidase, lysine oxidase, etc.
It is of great significance then, to design and develop a reliable and cost-effective method for H2O2 determination, which can generate a great impact in all the above-mentioned fields. Although several methods have already been proposed, electrochemical approaches present simple and compact tools able to provide great performance (high sensitivities and selectivity and low limits of detection).
A large number of electrochemical sensors have been described for the determination of hydrogen peroxide, either by direct detection or by using enzyme reactions which generate H2O2 as a byproduct. This thesis aims to contribute to the development of electrochemical analytical tools for H2O2 determination. The methodology used along the thesis varies depending on the strategy used to accomplish the goal. Thus, we can divide the thesis in two main blocks:
The first part of the thesis addresses the direct electrochemical determination of hydrogen peroxide by the integration of conducting polymers into the proposed electrodes. A general view of current works and methodologies in hydrogen peroxide detection using conducting polymers is described. The possibility of using alternative electrochemical techniques as the most reported ones is explored. Thus, the experimental part of this first block of the thesis aims at the development and characterization of conductometric and potentiometric sensors for the determination of hydrogen peroxide. Nevertheless, although having reached hydrogen peroxide detection in both tested strategies, the exact mechanism of the conducting polymer-hydrogen peroxide interaction is still beyond our reach, since in practical terms, reliable and reproducible sensors were not achieved.
The second part of the thesis aims at the indirect electrochemical determination of hydrogen peroxide, focused mainly on glucose detection through enzymatic reactions. First, the construction and characterization of assembled macro- and micro-electrodes for glucose determination using amperometric sensors is presented. In this case, although the entire project was not completed, the glucose detection through micro-electrodes was achieved.
In addition, and using a different approach, the characterization and validation of a potentiometric platinum paper-based sensor for glucose determination in saliva is also described. It is successfully presented as an alternative and noninvasive methodology for glucose quantification.
