A general problem encountered during the use of solid electrodes is the lowering of the electroanalytical response, caused by partial blocking of the surface by adsorbable reaction products. The use of polymeric materials to modify and protect the electrodes can minimize such alteration, allowing the detection of different species also in complex matrixes. Among different polymers, Nafion® is one of the most used [1-3], although scarcely studied and not appropriately designed for electrode modification. Sulphonated Poly (Aryl Ether Sulphones), commonly called S-PES, are engineered thermoplastic materials [4] that, due to their aromatic skeleton and charged sulphonic groups, present interesting properties: thermal and mechanical strength, resistance to oxidation and acid catalyzed hydrolysis, high glass transition temperature, good solubility in polar aprotic and halogenated solvents, radiation stability, low flammability and toughness, together with low costs. In this work, sulphonated Poly (Aryl Ether Sulphones) (S-PES), prepared by copolymerization with sulphonated monomers, have been studied as new materials for the production of modified electrodes for electroanalytical applications. A comparison with the use of Nafion® has been also made. After a complete characterization by Cyclic Voltammetry and Electrochemical Impedance Spectroscopy (EIS), the electroanalytical performances of the modified electrodes (sensitivity, LOD, LOQ, stability in air and solvent, ...) have been evaluated in function of different morphological and preparative parameters: the quantity and the form of the polymer (acidic, salt, with different macromolecular architecture, ...), different IECs, the method of drying, the casting solvent. The results demonstrate that 1 % linear PES in the acidic form, dried at 25 °C in a oven, after deposition from a N-Methylpyrrolidone solution presents the best performances in terms of higher voltammetric peak currents, more stability and less resistive behaviour, superior to Nafion®, maintaining the partial electrochemical and chemical reversibility and the diffusive control. [1] V. Pifferi, V. Marona, M. Longhi, L. Falciola, Electrochimica Acta, 109, (2013), 447-453. [2] L.M. Moretto, F. Montagner, R. Ganzerla, P. Ugo, Anal Bioanal Chem, 405, (2013), 3603-3610. [3] C.M.A. Brett, V.A. Alves, D.A. Fungaro, Electroanalysis, 13(3), (2001), 212-218. [4] R.T.S. Muthu Lakshmi, J. Meier-Haack, K. Schlenstedt, H. Komber, V. Choudhary and I.K. Varma, Reactive and Functional Polymers, 66 (6), (2006), 634–644.

Sulphonated Poly (Aryl Ether Sulphone) as electrode modifier in electroanalytical applications / V. Pifferi, L. Falciola, S. Checchia, H. Farina, M. Ortenzi. ((Intervento presentato al 65. convegno Annual Meeting of the International Society of Electrochemistry (ISE) tenutosi a Lausanne nel 2014.

Sulphonated Poly (Aryl Ether Sulphone) as electrode modifier in electroanalytical applications

V. Pifferi;L. Falciola;S. Checchia;H. Farina;M. Ortenzi
2014

Abstract

A general problem encountered during the use of solid electrodes is the lowering of the electroanalytical response, caused by partial blocking of the surface by adsorbable reaction products. The use of polymeric materials to modify and protect the electrodes can minimize such alteration, allowing the detection of different species also in complex matrixes. Among different polymers, Nafion® is one of the most used [1-3], although scarcely studied and not appropriately designed for electrode modification. Sulphonated Poly (Aryl Ether Sulphones), commonly called S-PES, are engineered thermoplastic materials [4] that, due to their aromatic skeleton and charged sulphonic groups, present interesting properties: thermal and mechanical strength, resistance to oxidation and acid catalyzed hydrolysis, high glass transition temperature, good solubility in polar aprotic and halogenated solvents, radiation stability, low flammability and toughness, together with low costs. In this work, sulphonated Poly (Aryl Ether Sulphones) (S-PES), prepared by copolymerization with sulphonated monomers, have been studied as new materials for the production of modified electrodes for electroanalytical applications. A comparison with the use of Nafion® has been also made. After a complete characterization by Cyclic Voltammetry and Electrochemical Impedance Spectroscopy (EIS), the electroanalytical performances of the modified electrodes (sensitivity, LOD, LOQ, stability in air and solvent, ...) have been evaluated in function of different morphological and preparative parameters: the quantity and the form of the polymer (acidic, salt, with different macromolecular architecture, ...), different IECs, the method of drying, the casting solvent. The results demonstrate that 1 % linear PES in the acidic form, dried at 25 °C in a oven, after deposition from a N-Methylpyrrolidone solution presents the best performances in terms of higher voltammetric peak currents, more stability and less resistive behaviour, superior to Nafion®, maintaining the partial electrochemical and chemical reversibility and the diffusive control. [1] V. Pifferi, V. Marona, M. Longhi, L. Falciola, Electrochimica Acta, 109, (2013), 447-453. [2] L.M. Moretto, F. Montagner, R. Ganzerla, P. Ugo, Anal Bioanal Chem, 405, (2013), 3603-3610. [3] C.M.A. Brett, V.A. Alves, D.A. Fungaro, Electroanalysis, 13(3), (2001), 212-218. [4] R.T.S. Muthu Lakshmi, J. Meier-Haack, K. Schlenstedt, H. Komber, V. Choudhary and I.K. Varma, Reactive and Functional Polymers, 66 (6), (2006), 634–644.
Settore CHIM/01 - Chimica Analitica
Settore CHIM/02 - Chimica Fisica
Sulphonated Poly (Aryl Ether Sulphone) as electrode modifier in electroanalytical applications / V. Pifferi, L. Falciola, S. Checchia, H. Farina, M. Ortenzi. ((Intervento presentato al 65. convegno Annual Meeting of the International Society of Electrochemistry (ISE) tenutosi a Lausanne nel 2014.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/387281
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