Chemical etching of emitter tips
AssigneeTrajan Scientific Australia Pty Ltd
InventorsKyle John James Bachus, Herbert Tze Cheung Foo, Heike Ebendorff-Heidepriem, Yvonne Marie Stokes, Josef Adam Giddings
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Abstract
A method of forming a capillary tube for electrospray ionization (ESI) having at least one tip with a desired tip profile. The method includes providing a pre-finished capillary tube of substantially homogenous material. The capillary tube has a first end and an internal bore. The first end of the pre-finished capillary tube is wet-etched in an etchant for an etch duration. A protective fluid flows through the internal bore of the capillary tube at a flow rate during the etch duration and the flow rate and the etch duration are determined to obtain the desired tip profile below a liquid level of the etchant.
Claims20
A method of forming a capillary tube for electrospray ionization (ESI) having at least one tip with a desired tip profile, the method comprising:
- providing a pre-finished capillary tube of substantially homogenous material, the capillary tube having a first end and an internal bore;
- and
- wet-etching the first end of the pre-finished capillary tube in an etchant for an etch duration and flowing a protective fluid through the internal bore of the capillary tube at a flow rate during the etch duration,
- wherein the flow rate and the etch duration are determined with a mathematical model that assumes a concentration gradient of etchant outwards from the outlet of the capillary with dilution over time to obtain the desired tip profile below a liquid level of the etchant.
A method of forming a capillary tube for ESI, the capillary tube having at least one tip, the method comprising:
- providing a pre-finished capillary tube having a first end, a longitudinal axis and an internal bore with an opening at the first end;
- and
- wet-etching the first end of the capillary tube in a liquid etchant for an etch duration and flowing a protective fluid through the internal bore of the capillary tube into the etchant, at a flow rate during the etch duration to obtain a desired emitter tip profile at the at least one emitter tip, the desired emitter tip profile approximating a cone which is defined by a peripheral wall having varying angles of inclination relative to the longitudinal axis which generally progress from higher to lower angles towards the opening of the internal bore;
- wherein the flow rate and the etch duration are determined with a mathematical model that assumes a concentration gradient of etchant outwards from the outlet of the capillary with dilution over time to obtain the desired tip profile.
Dependencies are inferred from the claim text.