Method and apparatus for characterizing materials by using a mechanical resonator

• US 7,073,370 B2
• Filed: 10/15/2003
• Issued: 07/11/2006
• Est. Priority Date: 10/08/1997
• Status: Expired due to Fees

• Current Assignee: Meas France
• Original Assignee: Symyx Technologies Incorporated (Dassault Systemes SA)
• Inventors: Bennett, James, Matsiev, Leonid, McFarland, Eric
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): MILLER, ROSE MARY
• Application Number:
  US10/686,444
• Publication Number:
  US 20040074303A1
• Time in Patent Office: 1,000 Days
• Field of Search: 73/240.1, 73 2403- 2406, 73/300.1, 73/300.4, 73/310.1, 73/310.2, 73/310.3, 73/310.5, 73/310.6, 73/32.A, 73/32.R, 73/530.1, 73/540.1, 73/540.2, 73/542.3, 73/544.1, 73/614.5, 73/617.5, 73/617.9, 735/79, 310/360, 310/316, 310/320, 422/68.1, 422/75, 422/98
• US Class Current: 73/24.06
• CPC Class Codes: B01J 2219/00704 integrated with the reactor apparatus
• CPC Class Codes: G01H 13/00 Measuring resonant frequency
• CPC Class Codes: G01N 11/16 by measuring damping effect upon oscillatory body
• CPC Class Codes: G01N 2009/006 vibrating tube, tuning fork
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0224 Mixtures of three or more liquids
• CPC Class Codes: G01N 2291/0255 (Bio)chemical reactions, e.g. on biosensors
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G01N 29/42 by frequency filtering or by tuning to resonant frequency
• CPC Class Codes: G01N 29/4418 with a model, e.g. best-fit, regression analysis
• CPC Class Codes: G01N 29/4427 with stored values, e.g. threshold values
• CPC Class Codes: G01N 29/4436 with a reference signal amplitude comparison G01N29/48
• CPC Class Codes: G01N 9/002 : using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence
• CPC Class Codes: G01N 9/34 : by using elements moving through the fluid, e.g. vane
• CPC Class Codes: G10K 11/02 : Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators

Abstract

A method and apparatus for measuring properties of a liquid composition includes a mechanical resonator, such as a cantilever, connected to a measurement circuit. The mechanical resonator can be covered with a coating to impart additional special detection propertied to the resonator, and multiple resonators can be attached together as a single sensor to obtain multiple frequency responses. The invention is particularly suitable for combinatorial chemistry applications, which require rapid analysis of chemical properties for screening. In one embodiment, the resonator is operated at a frequency of less than 1 MHz.

Claims

1. A sensor for characterizing a fluid, the sensor comprising a plurality of mechanical resonators having at least two different structures, the plurality of resonators comprising a low frequency tuning fork resonator and a high frequency tuning fork frequency resonator, the plurality of resonators being adapted for measuring physical or chemical properties of the fluid, at least one of the resonators having an operational frequency of less than 1 MHz, wherein the plurality of resonators are excited by a sweep generator.

2. The sensor of claim 1 wherein the plurality of resonators have different resonance frequencies.

3. The sensor of claim 2 wherein the plurality of resonators comprise different coatings, functionalities or combinations thereof.

4. The sensor of claim 3 further comprising at least one additional mechanical resonator.

5. The sensor of claim 1 further comprising a measurement circuit coupled with the resonators, the measurement circuit having a signal generator for generating a variable frequency input signal to cause the resonators to oscillate, and a receiver coupled to the measurement circuit to output a frequency response of the resonators.

6. The sensor of claim 1 wherein the plurality of resonators further comprise a thickness shear mode resonator.

7. The sensor of claim 3 wherein the plurality of resonators comprises different functionalities, each of the functionalities designed to bond with a different target molecule.

8. The sensor of claim 3 wherein the plurality of resonators comprise tuning fork resonators functionalized with a polymer layer or other selective absorbing layer to detect the presence of specific molecules in a vapor.

9. The sensor of claim 3 wherein the plurality of resonators comprise functionalized tuning fork resonators adapted to detect the presence of a specific chemical in a fluid composition.

10. The sensor of claim 3 wherein the plurality of resonators are tuning fork resonators treated with a functionality that changes the resonance frequency of the tuning fork upon exposure to a selected target chemical.

11. The sensor of claim 3 wherein the plurality of resonators are tuning fork resonators covered with receptor molecules that bond with specific target molecules.

12. The sensor of claim 3 wherein the plurality of resonators are tuning fork resonators functionalized with a material that physically changes when exposed to molecules of a selected chemical, such that the mechanical drag on the tuning fork changes upon exposure to the selected chemical.

13. The sensor of claim 3 wherein the plurality of resonators are tuning fork resonators comprising hydrophobic or hydrophilic functionality.

14. The sensor of claim 1 wherein the plurality of resonators are attached together by a common base.

15. The sensor of claim 1 wherein the resonators are adapted to operate in multiple mechanical modes.

16. The sensor of claim 15 wherein the multiple mechanical modes are selected from compression mode, axial mode, torsion mode or combinations thereof.

17. The sensor of claim 1 wherein tines of at least one of the tuning forks oscillate in opposite phases.

18. A sensor for characterizing a fluid, the sensor comprising a plurality of mechanical resonators having at least two different structures, the plurality of resonators comprising a low frequency tuning fork resonator and a high frequency tuning fork frequency resonator, the plurality of resonators being adapted for measuring physical or chemical properties of the fluid, at least one of the resonators having an operational frequency of less than 1 MHz wherein the plurality of resonators are attached to multiple frequency generating circuits adapted to measure properties of the fluid compositions over multiple frequency sweeps.

19. A sensor for characterizing a fluid, the sensor comprising:

a plurality of mechanical resonators, each of the plurality of resonators having an operational frequency of less than 1 MHz, the plurality of resonators being adapted for measuring physical or chemical properties of the fluid, and

a sweep generator for generating a variable frequency input signal to cause the resonators to oscillate,

wherein the plurality of resonators are selected from a low frequency tuning fork resonator, a high frequency tuning fork frequency resonator, a trident tuning fork resonator, a length extension resonator, a torsion resonator, a thickness shear mode resonator, bimorphs, unimorphs, and combinations thereof.

20. The sensor of claim 19 further comprising a measurement circuit coupled with the resonators, the measurement circuit comprising the sweep generator and a receiver coupled to the measurement circuit to output a frequency response of the resonators.

21. The sensor of claim 19 wherein the plurality of resonators have different structures, different resonance frequencies or combinations thereof.

22. The sensor of claim 21 wherein the plurality of resonators comprise different coatings, functionalities or combinations thereof.