A simple approach to compensate the suction caused by the electrospray ionization source in capillary electrophoresis-mass spectrometry systems

Author(s)

do Lago, Claudimir Lucio ; Rajh Vidal, Denis Tadeu ; Mendonca Francisco, Kelliton Jose ; dos Santos, Vagner Bezerra

• Document type: Journal article
• Source: ELECTROPHORESIS; v. 35, n. 16, p. 5-pg., 2014-08-01.

Abstract

ESI sources continuously consume the liquid at the tip of the capillary, which causes the dragging of the BGE. The laminar nature of this flow causes the broadening of the peaks and loss of separation efficiency. The usual solution for this problem is to compensate this phenomenon by reducing the pressure at the inlet vial by either leveling of this vial or pumping off the air that is over it. However, one must know the pressure to be applied in order to prevent under-or over-compensation. The procedure herein introduced allows the easy calculation of this pressure by obtaining two electropherograms at two different values of separation voltage. The migration times of the peaks allow the calculation of the apparent mobilities even in the presence of the laminar flow. Therefore, one can calculate the contributions from both electrophoresis and hydrodynamic flow, and finally the pressure associated with the undesirable flow. This pressure is then applied as a negative pressure at the inlet vial in the following experiments. Increase of up to 192% in the number of plates was obtained in a simple experiment. In addition, the bubble forming caused by the ESI suction during injection was prevented by turning off the nebulizer gas during the changes of inlet vials. (AU)

• FAPESP's process: 13/14993-1 - Characterization and quantification of monoalkyl carbonates in aqueous medium employing microfluidic devices coupled to a mass spectrometer
• Grantee: Vagner Bezerra dos Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/06642-1 - Formation and properties of adducts of organic hydroxy-compounds with carbonate in aqueous medium and biological conditions
• Grantee: Claudimir Lucio Do Lago
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/02156-2 - The use of capillary electrophoresis with contactless conductivity detection for obtaining analytical and physicochemical parameters of peroxycarbonate, peroxyacids, and monoethyl pyrocarbonate.
• Grantee: Denis Tadeu Rajh Vidal
• Support Opportunities: Scholarships in Brazil - Post-Doctoral