Sample component trapping, release, and separation with membrane assemblies interfaced to electrospray mass spectrometry

Abstract

The invention provides a method and apparatus for trapping, releasing and / or separating sample components in solution passing through a channel with or without packing material present by passing ion current through the channel driven by an electric field. A portion of the ion current comprises cation and / or anion species generated from second solution flows separated from the sample solution flow path by semipermeable membranes. Cation and / or Anion ion species generated in the second solution flow regions are transferred into the sample solution flow path through ion selective semipermeable membranes. Ion current moving along the sample solution flow path is controlled by varying the composition of the second solutions and / or changing the voltage between membrane sections for a given sample solution composition. The sample composition may also be varied separately or in parallel to enhance trapping, release and / or separation efficiency and range. The invention when interfaced to an Atmospheric Pressure Ion Source, that may include Electrospray Ionization, with mass spectrometric analysis enables independent control of the on-line sample separation process and the Atmospheric Pressure Ion Source or Electrospray ionization processes.

Description

RELATED PATENTS AND PATENT APPLICATIONS[0001]This application claims the priority of U.S. Provisional Patent Application Ser. No. 60 / 840,095, filed on Aug. 25, 2006, and is a continuation-in-part of U.S. patent application Ser. No. 11 / 803,984, filed on May 15, 2007, now U.S. Pat. No. 7,619,216, which is a continuation of U.S. patent application Ser. No. 11 / 132,953, filed on May 19, 2005, now U.S. Pat. No. 7,232,992. The contents of both U.S. Provisional Patent Application Ser. No. 60 / 840,095 and U.S. patent application Ser. No. 11 / 132,953 of which are incorporated herein by reference. U.S. Pat. No. 4,542,293 is also incorporated herein by reference.FIELD OF INVENTION [0002]This invention relates to the field of separation of sample components using electric fields and ion currents in solution with remote cation and / or anion species generation in solution flows off-line with non Mass Spectrometer detectors or integrated on-line with Electrospray Ionization or other Atmospheric Pressu...

AI Technical Summary

Benefits of technology

The present invention is a system that allows for controlled addition and removal of ions or neutral species in liquid chromatography, IEC, or Electrocapture packed or open solution channel analyte species separations. It uses semipermeable membranes to transfer ions or neutral species between a sample solution and another solution flow. The system can be integrated into an Electrospray ion source or other API source interfaced to a mass spectrometer. The invention allows for independent optimization of sample component separation and detector performance by controlling the ion current, cation or anion species, and sample solution composition. The system can be configured with different membrane assembly sections, packed LC columns, or open channel sections of the sample solution flow path. The invention can also be scaled up or down in size and sample solution flow rates to accommodate specific analytical applications. The system minimizes or eliminates pressure gradients across semipermeable membranes, reducing the risk of membrane failure and optimizing the effectiveness of membrane selectivity. The input sample solution flow composition can be run isocratically or as a gradient during a separation. The ion current gradients run through semipermeable membranes can be synchronized with a sample solution composition gradient to improve separation efficiency.

Problems solved by technology

None of these separation techniques are practiced with an ion current passing through the LC column.

The Electrocapture devices have no second solution flow to replenish charge in the anode and cathode reservoirs.

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