CHEMICAL IMPEDANCE DETECTORS FOR FLUID ANALYZERS

• US 20090184724A1
• Filed: 03/05/2009
• Published: 07/23/2009
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Bonne, Ulrich, Higashi, Robert, Nusseibeh, Fouad
• Granted Patent: US 7,965,089 B2
• Time in Patent Office: Days
• US Class Current: 324/663
• CPC Class Codes: G01F 1/6845 Micromachined devices
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/20 Rowland circle spectrometers
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 2021/058 Flat flow cell
• CPC Class Codes: G01N 2021/651 Cuvettes therefore
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G01N 27/02 by investigating impedance

Abstract

A chemical impedance detector having several electrodes situated on or across a dielectric layer of a substrate. The electrodes may be across or covered with a thin film polymer. Each electrode may have a set of finger-like electrodes. Each set of finger-like electrodes may be intermeshed, but not in contact, with another set of finger-like electrodes. The thin-film polymer may have a low dielectric constant and a high porous surface area. The chemical impedance detector may be incorporated in a micro fluid analyzer system.

Claims

1. An impedance detector comprising:

a substrate;

a dielectric layer situated on the substrate;

a first electrode situated on the dielectric layer;

a second electrode situated on the dielectric layer; and

a polymer layer situated on a portion of the first electrode, a portion of the second electrode, and an area of the dielectric layer between the first electrode and the second electrode; and

wherein;

the first and second electrodes are interdigitated electrodes; and

the polymer layer has a low dielectric constant due to a material property, and random pores and/or a MEMS-fabricated array of openings.

2. The detector of claim 1, wherein:

the first electrode comprises a first plurality of finger-like electrodes;

the second electrode comprises a second plurality of finger-like electrodes; and

wherein the first plurality of finger-like electrodes is intermeshed, but not in contact, with the second plurality of finger-like electrodes.

3. The detector of claim 2, wherein the electrodes comprise a porous structure.

4. The detector of claim 3, wherein the electrodes are low-height and low-width electrodes.

5. The detector of claim 1, wherein:

the substrate is silicon;

the dielectric layer is SiO₂;

the electrodes comprise conductive material; and

the polymer layer is a material having a low dielectric constant, porosity, and/or a high partition coefficient for a target analyte.

6. An impedance detector system, comprising:

a first interdigitated chemical impedance detector comprising;

a substrate;

a dielectric layer situated on the substrate;

a first electrode situated on the dielectric layer;

a second electrode situated on the dielectric layer; and

a polymer layer situated on the first electrode, the second electrode, and an area on the dielectric layer between the first and second electrodes; and

a second interdigitated chemical impedance detector comprising;

a substrate;

a dielectric layer situated on the substrate;

a first electrode situated on the dielectric layer;

a second electrode situated on the dielectric layer; and

a polymer layer situated on the first electrode, the second electrode, and an area on the dielectric layer between the first and second electrodes.

7. The system of claim 6, wherein the first and second chemical impedance detectors are connected in a differential mode.

8. The system of claim 7, wherein:

the first chemical impedance detector is exposable to an analyte; and

the second impedance detector is exposable to a reference sample, which may contain a different concentration of the analyte.

9. The system of claim 7, wherein the differential mode is an AC-coupled mode.

10. The system of claim 6, wherein:

the first electrode of the first chemical impedance detector comprises a first plurality of finger-like electrodes;

the second electrode of the first chemical impedance detector comprises a second plurality of finger-like electrodes;

the first electrode of the second impedance detector comprises a third plurality of finger-like electrodes;

the second electrode of the second chemical impedance detector comprises a fourth plurality of finger-like electrodes;

the first plurality of finger-like electrodes is intermeshed, but not in contact, with the second plurality of finger-like electrodes; and

the third plurality of finger-like electrodes is intermeshed, but not in contact, with the fourth plurality of finger-like electrodes.

11. The detector of claim 10, wherein:

the polymer layer has a low dielectric constant;

the polymer layer is a porous thin film layer;

the electrodes are low-height and low-width electrodes; and

the electrodes are porous.

12. The system of claim 6, further comprising:

an array of chemical impedance detectors; and

wherein;

the first and second chemical impedance detectors are in the array of chemical impedance detectors; and

each chemical impedance detector comprises;

a substrate;

a dielectric layer situated on the substrate;

a first electrode situated on the dielectric layer;

a second electrode situated on the dielectric layer; and

a polymer situated on the first electrode, the second electrode, and an area on the dielectric layer between the first and second electrodes.

13. The system of claim 12, wherein:

the first electrode situated on the dielectric layer comprises a first plurality of narrow and lengthy electrodes;

the second electrode of the chemical impedance detector comprises a second plurality of narrow and lengthy electrodes; and

the first plurality of narrow and lengthy electrodes is intermeshed, but not in contact, with the second plurality of narrow and lengthy electrodes.