Nanomaterials as sensitive electroanalytical platforms

Abstract

Organization of nanomaterials onto controlled surface architectures is essential for the successful realization of the sensing protocols. To this regard, the present thesis explored three major areas, which include the integration of nanomaterials on solid supports, the preparation of hybrid nanomaterials, and the application of nanomaterials as electroanalytical platforms for the sensitive detection of various analytes. For the integration of nanomaterials on solid supports, the performance of two types of electrochemical interfaces, the novel superhydrophilic indium-tin oxide (ITO) base electrode and hydrophobic ITO base electrode, was compared in chapter 3. A novel electrochemical platform using the self-assembly of aromatic dithiol molecules and gold nanoparticles (Au NPs) by layer by layer assembly is demonstrated in chapter 4. In chapters 5-9, a simple and single step method for modifying electrode surfaces, film deposition is also used to immobilize nanomaterials, composite or functionalized nanomaterials on solid electrodes. Specific examples include the film deposition of single-walled carbon nanotubes (SWCNTs), methylene blue (MB)-functionalized SWCNT, SWCNT-Au NP composite, and carbon nanochips (CNCs) on glassy carbon electrode (GCE). In the preparation of hybrid nanomaterials, MB-functionalized SWCNT was prepared and its electrochemical studies were conducted. A composite of SWCNTs and Au NPs was also used to modify a GCE to form SWCNT-Au NP composite. In the application of nanomaterials as electroanalytical platforms for the sensitive and selective detection of various analytes simultaneously, the experimental method involves a single step, environmentally friendly and rapid. The enrichment of analytes takes place between the nanomaterial and aqueous samples. A novel method for the easy identification of electrode reaction products, provided that the species formed are stable and adhere to the electrode, is also developed using the SWCNT modified GCE. The modification of the electrode surface with CNCs has been demonstrated to be an efficient direct electron transfer between electrodes and redox active proteins. The results obtained from the present research clearly show that nanomaterials can be used as excellent electroanalytical platforms for the trace analysis of various matrix samples including environmental samples and biological fluids and the remarkable properties of nanomaterials in electroanalytical applications appeared to be far more superior to conventional methods.