DEVELOPMENT OF MINIATURIZED ANALYTICAL SYSTEMS FOR DETERMINATION OF ORGANIC COMPOUNDS AND HEAVY METALS

Abstract

This dissertation focused on the development of novel miniaturized analytical systems for the determination of several analytes of interest, which can be divided into 2 sections. The first section is the development of alternative methods for the measurement of organic compounds using paper-based/polymer-based analytical device coupled with electrochemical detection. Various target organic compounds including dopamine, glucose, and 4-aminophenol were determined by the proposed systems. The second section is the development of paper-based colorimetric/electrochemical device for the simultaneous quantification of heavy metals (e.g. chromium, nickel, copper, iron, lead, and cadmium). Miniaturized systems were initially designed to allow the appropriate geometry for each assay. Experimental parameters in the detection mode were optimized and selected in order to determine the best analytical conditions. Strategies to improve the selectivity and sensitivity in analysis were discussed. An analytical performance of the system comprising of linearity, limit of detection, limit of quantification, reproducibility, accuracy, intra-day, and inter-day precision, was investigated. Selectivity for the detection of analytes of interest was demonstrated for common interferences. The results showed that the accuracy and precision of these proposed systems were reported in an acceptable range lower than 5%. A low detection limit was achieved (e.g. 14.8 pmol and 5.8 nmol for detection dopamine and glucose, respectively). In addition, the developed systems were successfully applied to the determination of target analytes in samples (e.g. relevant biological, pharmaceutical, and environmental samples) with satisfactory results, correlating to those obtained from the conventional analytical techniques.