Métodos De Injeção Da Amostra Em Microssistemas Eletroforéticos

Abstract

SAMPLE INJECTION METHODS IN ELECTROPHORETIC MICROSYSTEMS. Electrophoresis is by far the most popular separation method implemented in microscale, most probably due to its instrumental simplicity, low cost and portability. Due to the increasing use of miniaturized electrophoretic systems, the study of fundamental aspects can improve the development of methodologies for several applications. One of the major challenges related to electrophoresis chips refers to the sample injection mode, in this way, this study presents a review on sample injection methods for microchip electrophoresis covering electrokinetic and hydrodynamic approaches, describing theoretic and instrumental aspects. Since the sample volume affects the analytical performance, the precise and reproducible control of the sample amount to be introduced into the separation channel is highly desirable to ensure reliable chemical analysis. Electrokinetic modes based on floating, pinched and gated protocols are presented and discussed providing an overview about the electrokinetic control of the sample through three methodologies. In the same way, hydrodynamic techniques including the use of microfabricated valves and pumps, syringe pumps, electronic micropipettes, rubber suction bulb and acupuncture needle are approached, thus expanding the view of hydrodynamic injectors based on classical and alternative methods.