Miniaturized device for ion analysis, and methods of use thereof

• US 6,489,774 B1
• Filed: 07/08/1999
• Issued: 12/03/2002
• Est. Priority Date: 07/08/1999
• Status: Expired due to Term

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: van de Goor, Tom A, Kaltenbach, Patrick
• Primary Examiner(s): Sherry, Michael
• Assistant Examiner(s): HOLLINGTON, JERMELE M
• Application Number:
  US09/349,862
• Time in Patent Office: 1,244 Days
• Field of Search: 324/439, 324/441, 324/443
• US Class Current: 324/439
• CPC Class Codes: G01N 27/4473 by electric means
• CPC Class Codes: G01N 27/44791 Microapparatus sample containers with integrated microfluidic structures B01L3/5027

Abstract

A miniaturized ion analysis system with a contactless conductivity detection means is described for use in liquid phase sample analysis and detection. The device is formed by microfabrication of microstructures in novel support substrates. The detection means can be fabricated directly in the support body at the point of detection or other locations on the device or, alternatively, may be formed as part of a modular structure that is insertable into the device at the point of detection. In addition, a method is provided for analyzing ionic species present in a sample using the miniaturized ion analysis device. The invention herein is used for the analysis of ionic solutes in the liquid phase.

Claims

1. A method for analyzing ionic species present in a sample, comprised of:

(a) providing a miniaturized ion analysis system for sample preparation and analysis comprising;

a microfabricated support body having first and second substantially planar opposing surfaces wherein the support body has a microchannel microfabricated in the first planar surface,

a cover plate arranged over the first planar surface, wherein the cover plate in combination with the microchannel forms a sample flow compartment,

an inlet port and an outlet port communicating with the sample flow compartment, wherein the inlet and outlet ports enable passage of fluid from an external source through the sample flow compartment, and

a contactless conductivity detection (“

CCD”

) means in electrical communication with the sample flow compartment such that the detection means is capable of detecting the presence in the sample flow compartment of a fluid containing a detectable ionic species;

(b) flushing the sample flow compartment with a leading electrolyte;

(c) introducing a sample into the sample flow compartment such that the sample is in fluidic and ionic communication with the leading electrolyte;

(d) introducing a terminating electrolyte into the sample flow compartment such that the sample is in fluidic and ionic communication with the terminating electrolyte;

(e) stacking the ionic species present in the sample by applying a current across the leading and terminating electrolytes to provide stacked ionic species;

(f) preseparating the stacked ionic species; and

(g) detecting the presence in the sample flow compartment of the pre-separated stacked ionic species.

2. The method of step 1, further comprising flushing the sample through the sample flow compartment to determine the conductivity of the sample before step (e).

3. The method of step 1, further comprising situating a CCD means over the inlet port, and, concurrently with step (e) applying a counterbore sufficient to counteract an electroosmotic flow.

4. A method for analyzing ionic species present in a sample, comprising:

(a) providing a miniaturized ion analysis system for sample preparation and analysis comprising,

a microfabricated support body having first and second component halves each having substantially planar opposing interior and exterior surfaces,

a first microchannel microfabricated in the interior surface of the first support body half and a second microchannel microfabricated in the interior surface of the second support body half, wherein each of the microchannels is so arranged as to provide the mirror image of the other,

an elongate bore formed by aligning the interior surfaces of the support body halves in facing abutment with each other whereby the microhchannels define a sample flow compartment,

an inlet port and an outlet port communicating with the sample flow compartment, wherein the inlet and outlet ports enable passage of fluid from an external source through the sample flow compartment, and

a contactless conductivity detection (“

CCD”

) means in electrical communication with the sample flow compartment such that the detection means is capable of detecting the presence in the sample flow compartment of a fluid containing a detectable ionic species;

(b) flushing the sample flow compartment with a leading electrolyte;

(c) introducing a sample into the sample flow compartment such that the sample is in fluidic and ionic communication with the leading electrolyte;

(d) introducing a terminating electrolyte into the sample flow compartment such that the sample is in fluidic and ionic communication with the terminating electrolyte;

(e) stacking the ionic species present in the sample by applying a current across the leading and terminating electrolytes to provide stacked ionic species;

(f) preseparating the stacked ionic species; and

(g) detecting the presence in the sample flow compartment of the stacked ionic species.

6. The method of claim 4, further comprising situating a CCD means over the inlet port, and, concurrently with step (e) applying a counterbore sufficient to counteract an electroosmotic flow.

5. The method of step 4, further comprising flushing the sample through the sample flow compartment to determine the conductivity of the sample before step (e).