Integrated monolithic microfabricated electrospray and liquid chromatography system and method

• US 6,432,311 B2
• Filed: 12/21/2000
• Issued: 08/13/2002
• Est. Priority Date: 09/17/1998
• Status: Expired due to Term

• Current Assignee: Rheonix, Inc.
• Original Assignee: Kionix Incorporated (ROHM Co., Ltd.)
• Inventors: Davis, Timothy J., Moon, James E., Galvin, Gregory J.
• Primary Examiner(s): Therkorn, Ernest G.
• Application Number:
  US09/745,779
• Publication Number:
  US 20010001456A1
• Time in Patent Office: 600 Days
• Field of Search: 250/288, 250/288.A, 210/656, 210/748, 210/198.2, 210/243, 204/600, 204/450, 422/70, 436/161
• US Class Current: 210/656
• CPC Class Codes: G01N 30/6095 Micromachined or nanomachined, e.g. micro- or nanosize
• CPC Class Codes: G01N 30/7266 by electric field, e.g. electrospray
• CPC Class Codes: H01J 49/0018 Microminiaturised spectrometers, e.g. chip-integrated devices, Micro-Electro-Mechanical Systems [MEMS]
• CPC Class Codes: H01J 49/167 Capillaries and nozzles specially adapted therefor; electrostatic spraying per se B05B5/00
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]
• CPC Class Codes: Y10T 436/255 including use of a solid sorbent, semipermeable membrane, or liquid extraction

Abstract

An electrospray device, a liquid chromatography device and an electrosprayliquid chromatography system are disclosed. The electrospray device comprises 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 electrode for application of an electric potential to the substrate to optimize and generate an electrospray; and, optionally, additional electrode(s) to further modify the electrospray. The liquid chromatography device comprises a separation substrate defining an introduction channel between an entrance orifice and a reservoir and a separation channel between the reservoir and an exit orifice, the separation channel being populated with separation posts perpendicular to the fluid flow; a cover substrate bonded to the separation substrate to enclose the reservoir and the separation channel adjacent the cover substrate; and, optionally, electrode(s) for application of a electric potential to the fluid. The exit orifice of the liquid chromatography device may be homogeneously interfaced with the entrance orifice of the electrospray device to form an integrated single system. An array of multiple systems may -be fabricated in a single monolithic chip for rapid sequential fluid processing and generation of electrospray for subsequent analysis, such as by positioning the exit orifices of the electrospray devices near the sampling orifice of a mass spectrometer.

Claims

1. A method of performing chemical separation of an analyte using a chemical separation system, comprising the steps of:

forming, at least in part by reactive ion etching, an enclosed fluid reservoir, an entrance opening, and a channel extending from said entrance opening to said fluid reservoir;

forming, at least in part by reactive ion etching, an exit and an enclosed separation channel, said separation channel having a plurality of posts and extending from said fluid reservoir to said exit;

introducing by external means a stationary phase fluid to said entrance opening and applying pressure to said fluid to force said fluid into said reservoir;

causing said stationary phase fluid to flow from said reservoir through said separation channel to said exit, thereby coating said plurality of posts with stationary phase fluid;

fixing said stationary phase fluid on said plurality of posts through at least one of thermal treatment and forced flow of a drying gas;

introducing by external means said analyte to said entrance opening and applying pressure so as to force said analyte into said reservoir; and

causing said analyte to flow from said reservoir through said separation channel to said exit by at least one of applying pressure and using an electrokinetic technique, thereby effecting said desired separation of said analyte.