Experimental and theoretical investigations of the dielectric barrier electrospray in respect to μ-chip development

Abstract

The electrospray ionization source is an interface between the separation techniques and mass spectrometry. With the help of electrospray the analyte ions of the liquid phase are transferred to the gas phase, which is necessary for the mass spectrometry detection method. The spraying of the analyte occurs in the high electric field applied between the emitter tip and mass spectrometer inlet. In the conventional electrospray the high electric field is produced by the application of the high potential to the analyte with a direct contact electrode. In an alternative method the high potential is applied to the analyte through a thin dielectric barrier. The displacement current in the dielectric material is utilized to transfer the charge to the analyte. The goal of current research is the further development by DB-ESI source, the detailed analysis of advantages of the ionization technique and possible issues comparing to the conventional electrospray ionization systems. The electrospray formation process is investigated with the experimental work and physical modeling. The effects discovered in the DB-ESI capillary system allow the optimization of the electrospray system parameters for the effective control and improvement of the mass spectrometer absolute signal intensity. The DB-ESI source integration in a µ-Chip is demonstrated. In contrast to the common nozzle-type emitter shapes, the electrospray out of the flat-surface outlet is discussed. The proposed µ-Chip structure opens vast opportunities for further development, including the manufacturing of the µ-Chips with multiple channels and emitters.