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Construction and application of 2D and 3D electrochemical paper-based analytical devices

Author(s):
Murilo Santhiago
Total Authors: 1
Document type: Doctoral Thesis
Institution: Universidade Estadual de Campinas. Instituto de Química
Defense date:
Examining board members:
Wendell Karlos Tomazelli Coltro; Lúcio Angnes; Juliano Alves Bonacin; José Alberto Fracassi da Silva
Advisor: Lauro Tatsuo Kubota
Abstract

This thesis describes the construction and application of 2D and 3D electrochemical paper-based analytical devices (ePADs). The devices were constructed using the wax printing method and different types of papers. Gold electrodes were employed along with the concept of chromatographic separation in microfluidic devices. By using the paper-based microfluidic channel it was possible to perform the separation of ascorbic acid and dopamine in 14 minutes. The need for simpler and low cost manufacturing processes motivated us to study carbon electrodes in ePADs. Thus, pencil graphite electrodes were selected for the development of a biosensor for glucose. The biosensor exhibited excellent electrochemical response and analysis time of 4 minutes. The same graphite electrode was coupled to an information system for the determination of p-nitrophenol. Thus, it was possible to detect 1.0 mmol L of p-nitrophenol in water samples and analyze/interpret the results using a smartphone. Finally, the need for electrochemical systems with lower limits of detection made us to search for carbon paste microelectrodes. The microelectrodes were fabricated on transparency sheets and coupled on paper using a sandwich-type configuration. The devices were characterized electrochemically in the presence of cysteine and had a rate constant of 10 L mol s. A detection limit of 4.8 mmol L for cysteine was obtained using an array of microelectrodes. By last, carbon paste microelectrodes were used to construct a biosensor in order to determine methyl parathion. The ePAD was constructed to accommodate the substrate (acetylthiocholine ) and enzyme ( acetylcholinesterase ) in the same device. (AU)

FAPESP's process: 10/00226-0 - Construction and application of analytical microdevices based on chromatographic paper with amperometric detection
Grantee:Murilo Santhiago
Support type: Scholarships in Brazil - Doctorate