DEVELOPMENT OF ELECTROCHEMICAL METHODS FOR THE DETECTION OF VITAMIN B2, VITAMIN B6, VITAMIN C, ALBUMIN, AND L-HYDROXYPROLINE

Abstract

This dissertation aims to develop simple and effective electrochemical methods for the detection of important analytes. The study was divided into two parts. The first part focused on the development of a simple electrochemical approach for the simultaneous detection of vitamin B2, vitamin B6, and vitamin C using a modifier-free screen-printed carbon electrode. This work emphasized the investigation of the effect of supporting electrolytes on the electrochemical behavior of each vitamin. The second part of this dissertation presented two subprojects that reported on the development of electrochemical methods for detecting biomarkers. The first subproject described the development of a simple and rapid approach for detecting urinary albumin on a paper-based analytical device using an electrochemical-chemical redox cycling process. This strategy highlighted the use of a unique combination of ferricyanide and methylene blue for signal amplification, without any electrode surface modification. The second subproject involved the development of a new sensing device for detecting L-hydroxyproline (Hyp) using a screen-printed graphene electrode (SPGE) coated with bismuth film (BiF) and poly(L-hydroxyproline) (Poly(Hyp)). This sensor (Poly(Hyp)/BiF/SPGE) can be fabricated by two simple modification processes: (1) the electrodeposition of BiF; and (2) the electropolymerization of Poly(Hyp). Therefore, all electrochemical methods presented in this dissertation were primarily based on simplicity and effectiveness with good analytical performance that can be applied to detect target analytes in various practical applications, such as food quality control and clinical diagnosis.-