A Polypyrrole Based Sensor for the Electrochemical Detection of OH Radicals

Abstract

Polypyrrole was used as sensitive material in the development of a new device employed for the indirect detection of OH radicals. The polypyrrole film was electrosynthesized on glassy carbon. The modified electrode was exposed to the OH radicals generated by Fenton reaction. As a result of the overoxidation the conductivity of the polymer diminished very much. The overoxidation (%) was directly proportional to the .OH amount that reached the electrode surface. ABTS.+, superoxide and alkylperoxy radicals did not interfere in the determination. The applicability of the device was demonstrated by estimating the .OH scavenging ability of ascorbic acid.

Poly(methylene blue)-modified electrode for indirect electrochemical sensing of OH radicals and radical scavengers

“…This pro-oxidative capacity of ascorbic acid is in accordance with previous results reported in literature (Berger et al 1997, Carr and Frei 1999, Valko et al 2005. However, in the few studies related to chemically modified electrodes (CMes) for OH · sensing (Gualandi et al 2014, Gualandi and Tonelli 2013, Scholz et al 2007, Hilgemann et al 2010, it is the first time that such behavior is observed concerning this pro-oxidative effect of AA when it is used as an antioxidant. Thus, in these cases, low AA levels should be maintained.…”

“…In this sense, electrochemical assays are promising tools: suitable for fast analyses, based on inexpensive instrumentation and with simple operation protocols (Prieto-Simón et al 2008). Additionally, studies propose the use of chemically modified electrodes (CMEs) as a simple electrochemical approach to sense ROS and radical scavengers, with DNA, selfassembled monolayers of thiols, polyphenol films, and conducting polymers (CPs) (Scholz et al 2007, Liu et al 2005, Mello et al 2006, Hilgemann et al 2010, Wu et al 2012, Gualandi and Tonelli 2013, Gualandi et al 2014 as electrode modifiers. The ROS may attack the CME and the extent of the modifier destruction can be evaluated directly (in this case, when an electroactive layer is monitored) or using an electrochemical probe in solution (when a non-electroactive layer is used).…”

“…The ROS may attack the CME and the extent of the modifier destruction can be evaluated directly (in this case, when an electroactive layer is monitored) or using an electrochemical probe in solution (when a non-electroactive layer is used). Besides acting as radical probes (Gualandi et al 2014), conducting polymers (CPs) can be used as a component in biosensors in order to detect ROS (Rajesh et al 2010, Mahmoudian et al 2013. In addition to that, the use of CPs in sensor technologies involves employing the conducting polymers as an electrode modification in order to improve sensitivity, to impart selectivity, to suppress interference and to provide a support matrix for sensor molecules (Inzelt 2008).…”

Eletropolimerização de azul de metileno sobre carbono vítreo e estabilidade do filme de poli(azul de metileno)

“…Por razões práticas, polímeros condutores que podem ser preparados a partir de compostos baratos, como anilina, pirrol, flavinas e seus derivados, através de um processo relativamente simples de polimerização eletroquímica, atraem grande interesse. Entretanto, polímeros redox também são aplicados em casos especiais, como em biossensores ou aparelhos eletroquímicos [2][3][4][5][6][7]. O uso de PCs na tecnologia de sensores envolve utilizá-los como uma modificação da superfície de um eletrodo para aumentar sua sensibilidade, transmitir seletividade, diminuir interferências e providenciar uma matriz de suporte para as moléculas do sensor [1].…”

Synthesis and characterization of dendritic polypyrrole silver nanocomposite and its application as a new urea biosensor

“…In recent years, the conductive polymer nanostructures have acquired notable importance in nanoscience and technology . One of the most promising among conducting polymers is polypyrrole due to its good environmental stability, high biocompatibility, very good mechanical, thermal, and electrical properties. Polypyrrole has wide applications as sensor, electrochemical capacitance, rechargeable batteries, metal separation, membrane, and so forth.…”