Multiple electrospray device, systems and methods

• US 6,723,985 B2
• Filed: 01/23/2003
• Issued: 04/20/2004
• Est. Priority Date: 12/30/1999
• Status: Expired due to Term

• Current Assignee: Advion, Inc. (Beijing Bohui Innovation Biotechnology Group Co., Ltd.)
• Original Assignee: Advion BioSciences Incorporated
• Inventors: Schultz, Gary A., Corso, Thomas N., Prosser, Simon J.
• Primary Examiner(s): Wells, Nikita
• Application Number:
  US10/350,542
• Publication Number:
  US 20030143493A1
• Time in Patent Office: 453 Days
• Field of Search: 250/288, 250/281, 250/282, 250/423.R, 430/320, 430/314, 210/198.2, 210/748
• US Class Current: 250/288
• CPC Class Codes: H01J 49/0018 Microminiaturised spectrometers, e.g. chip-integrated devices, Micro-Electro-Mechanical Systems [MEMS]
• CPC Class Codes: H01J 49/04 Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components
• CPC Class Codes: H01J 49/167 Capillaries and nozzles specially adapted therefor; electrostatic spraying per se B05B5/00

Abstract

A microchip-based electrospray device, system, and method of fabrication thereof are disclosed. The electrospray device includes a substrate defining a channel between an entrance orifice on an injection surface and an exit orifice on an ejection surface, a nozzle defined by a portion recessed from the ejection surface surrounding the exit orifice, and an electric field generating source for application of an electric potential to the substrate to optimize and generate an electrospray. A method and system are disclosed to generate multiple electrospray plumes from a single fluid stream that provides an ion intensity as measured by a mass spectrometer that is approximately proportional to the number of electrospray plumes formed for analytes contained within the fluid. A plurality of electrospray nozzle devices can be used in the form of an array of miniaturized nozzles for the purpose of generating multiple electrospray plumes from multiple nozzles for the same fluid stream. This invention dramatically increases the sensitivity of microchip electrospray devices compared to prior disclosed systems and methods.

Claims

1. A method of producing an electrospray device comprising:

providing a substrate having opposed first and second surfaces, the first side coated with a photoresist over an etch-resistant material;

exposing the photoresist on the first surface to an image to form a pattern in the form of at least one ring on the first surface;

removing the exposed photoresist on the first surface which is outside and inside the at least one ring leaving the unexposed photoresist;

removing the etch-resistant material from the first surface of the substrate where the exposed photoresist was removed to form holes in the etch-resistant material;

optionally, removing all photoresist remaining on the first surface;

coating the first surface with a second coating of photoresist;

exposing the second coating of photoresist within the at least one ring to an image;

removing the exposed second coating of photoresist from within the at least one ring to form at least one hole;

removing material from the substrate coincident with the at least one bole in the second layer of photoresist on the first surface to form at least one passage extending through the second layer of photoresist on the first surface and into substrate;

optionally removing all photoresist from the first surface;

applying an etch-resistant layer to all exposed surfaces on the first surface side of the substrate;

removing the etch-resistant layer from the first surface that is around the at least one ring;

removing material from the substrate exposed by the removed etch-resistant layer around the at least one ring to define at least one nozzle on the first surface;

providing a photoresist over an etch-resistant material on the second surface;

exposing the photoresist on the second surface to an image to form a pattern circumscribing extensions of the at least one hole formed in the etch-resistant material of the first surface;

removing the exposed photoresist on the second surface;

removing the etch-resistant material on the second surface coincident with where the photoresist was removed;

removing material from the substrate coincident with where the etch-resistant material on the second surface was removed to form a reservoir extending into the substrate to the extent needed to join the reservoir and the at least one passage; and

applying an etch-resistant material to all surfaces of the substrate to form the electrospray device.

2. The method according to claim 1, wherein the substrate is made from silicon and the etch-resistant material is silicon dioxide.

3. The method according to claim 1 further comprising:

applying a silicon nitride layer over all surfaces after said applying an etch-resistant material to all exposed surfaces of the substrate.

4. The method according to claim 3 further comprising:

applying a conductive material to a desired area of the substrate.

5. A method of producing an electrospray device comprising:

providing a substrate having opposed first and second surfaces, the first side coated with a photoresist over an etch-resistant material;

exposing the photoresist on the first surface to an image to form a pattern in the form of at least one ring on the first surface;

removing the exposed photoresist on the first surface which is outside and inside the at least one nag leaving the unexposed photoresist;

removing the etch-resistant material from the first surface of the substrate where the exposed photoresist was removed to form holes in the etch-resistant material;

optionally, removing all photoresist remaining on the first surface;

providing a photoresist over an etch-resistant material on the second surface;

exposing the photoresist on the second surface to an image to form a pattern circumscribing extensions of the at least one ring formed in the etch-resistant material of the first surface;

removing the exposed photoresist on the second surface;

removing the etch-resistant material on the second surface coincident with where the photoresist was removed;

removing material from the substrate coincident with where the etch-resistant material on the second surface was removed to form a reservoir extending into the substrate; and

optionally removing the remaining photoresist on the second surface;

coating the second surface with an etch-resistant material;

coating the first surface with a second coating of photoresist;

exposing the second coating of photoresist within the at least one ring to an image;

removing the exposed second coating of photoresist from within the at least one ring to form at least one hole;

removing material from the substrate coincident with the at least on hole in the second layer of photoresist on the first surface to form at least one passage extending through the second layer of photoresist on the first surface and into substrate to the extent needed to reach the etch-resistant material coating the reservoir;

removing at least the photoresist around the at least one ring from the first surface;

removing material from the substrate exposed by the removed etch-resistant layer around the at least one ring to define at least one nozzle on the first surface;

removing from the substrate at least the etch-resistant material coating the reservoir; and

applying an etch resistant material to coat all exposed surfaces of the substrate to form the electrospray device.

6. The method according to claim 5, wherein the substrate is made from silicon and the etch-resistant material is silicon dioxide.

7. The method according to claim 5 further comprising:

applying a silicon nitride layer over all surfaces after said applying an etch-resistant material to all exposed surfaces of the substrate.

8. The method according to claim 7 further comprising:

applying a conductive material to a desired area of the substrate.