Microfluidic Interfaces for Coupling Hydrodynamic to Electrokinetic Flow and Microchannel Electrophoresis to Electrospray Ionization-Mass Spectrometry



Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Aaron T. Timperman.


Presented in this dissertation is a microfluidic interface for coupling hydrodynamic and electrokinetic flows, this interface was first studied theoretically and then experimentally to evaluate the electrophoretic extraction of a negatively charged analyte from a perpendicular hydrodynamic flow stream. Secondly the interface was used to perform the simultaneous extraction and separation of a cationic peptide and anionic proteins with low electroosmotic flow.;In addition, two important aspects of creating a microfluidic device to couple microchannel electrophoresis with mass spectrometry using electrospray ionization were also studied. These aspects included the electrospray emitter from which the electrospray originates and the incorporation of the electrospray electrode, that helps define the electric field over the separation channel, applies the electrospray voltage, and sinks excess current. The electrospray emitters studied consisted of a series of emitters with differing geometries and inner and outer dimensions. The different emitters were evaluated using different electrospray voltages and hydrodynamic flow rates. The optimum intensities for each emitter, as well as the best ion utilization for each emitter are reported.;Finally, an interface for integration of the electrospray electrode was studied experimentally and theoretically. The study consisted of measuring the peak area of a band of injected analyte before and after migration through a novel voltage switching intersection. Measurement of the peak area facilitated the determination of the transmission of analyte through the intersection, which was subsequently compared to a mathematical model of the intersection.

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