METHOD DEVELOPMENT, OPTIMIZATION AND APPLICATIONS OF CAPILLARY ELECTROPHORESIS

Abstract

This work focuses on the method development, optimization and applications of high performance capillary electrophoresis (CE). Buffer modifiers or additives were used either singly or in combination for the optimization of separation for a wide range of compounds such as antibiotics, food additives, drug substances and environmental pollutants. Satisfactory separations were achieved with CE methods based on the use of modifiers such as tetraalkylammonium salts, cyclodextrins, urea and bile salts. Without the use of these modifiers, optimum separation would not have been achieved with the use of conventional methods such as CZE, MEKC or other established techniques. A new method using a totally organic mobile phase for the separation of some selected anti-cancer drugs was also developed. To minimize the number of trials of experimentation before a separation was optimized, a systematic optimization scheme was developed for CE. In this scheme, two parameters were varied (pH and modifier concentrations) according to a certain number of preplanned experiments. The resolution plots generated were overlapped and the best separation between peaks was chosen. The validity of the scheme was verified by applying the chosen optimized conditions and optimum separation was obtained for the groups of compounds used. A combined packed and open tubular column was developed for the separation of fast eluting small molecules. A method based on the use of a tri-block copolymer as the coating material for coating the inner wall or the capillary to prevent protein adsorption was also developed The ease of the coating procedure and the high efficiency of the column were demonstrated. Lastly, the usefulness or CE was demonstrated by applying the methods developed above in the analysis or real-life samples such as environmental pollutants, natural products, antibiotics, pharmaceuticals and drug substances.