Method and apparatus for characterizing materials by using a mechanical resonator

• US 20040074303A1
• Filed: 10/15/2003
• Published: 04/22/2004
• Est. Priority Date: 10/08/1997
• Status: Active Grant

• Current Assignee: Meas France
• Original Assignee: Symyx Technologies Incorporated (Dassault Systemes SA)
• Inventors: Bennett, James, Matsiev, Leonid, McFarland, Eric
• Granted Patent: US 7,073,370 B2
• Time in Patent Office: Days
• US Class Current: 73/579
• 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.

Claims

1. :

A sensor for characterizing a fluid composition, the sensor comprising a plurality of mechanical resonators in combination, the plurality of resonators being adapted for measuring physical or chemical properties of the fluid composition.

2. :

The sensor of claim 1 wherein the plurality of resonators have different structure, different resonance frequencies and combinations thereof.

3. :

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

4. :

The sensor of claim 3 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, membrane oscillators, bimorphs, unimorphs, surface acoustic wave devices, and combinations thereof.

5. :

The sensor of claim 4, wherein the resonators within the array are simultaneously operated in different modes of oscillation selected from self-oscillating, excited by the sweep generator, operated in free decay mode, and combinations thereof.

6. :

The sensor of claim 5 further comprising a measurement circuit coupled with the resonators, said measurement circuit having a signal generator for generating a variable frequency input signal to cause the resonators to oscillate, a receiver coupled to the measurement circuit to output a frequency response of the resonators, a receiver coupled to the measurement circuit to output free decay response of the resonator, a self-oscillating unit in a feedback loop with the said resonators to cause the resonators to oscillate, a gain control unit for keeping the amplitude of oscillation at a constant level, a pulse generator that provides shock excitation to the said resonator and combinations thereof.

7. :

The sensor of claim 2 wherein the plurality of resonators comprise a tuning fork resonator and a thickness shear mode resonator.

8. :

The sensor of claim 2 wherein the plurality of resonators comprise a low frequency tuning fork resonator and a high frequency tuning fork frequency resonator.

9. :

The sensor of claim 3 wherein the plurality of resonators have the same structure.

10. :

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

11. :

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.

12. :

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.

13. :

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.

14. :

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

15. :

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.

16. :

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

17. :

The sensor of claim 4 wherein the signal generator is adapted for generating an input signal at a frequency of less than 1 MHz.

18. :

The sensor of claim 6 wherein the plurality of resonators are attached together by a common base.

19. :

The sensor of claim 6 wherein the plurality of resonators are attached to multiple frequency generating circuits adapted to measure properties of the fluid compositions over multiple frequency sweeps.