Liquid expansion thermometer and microcalorimeter

• US 20060133951A1
• Filed: 12/08/2005
• Published: 06/22/2006
• Est. Priority Date: 12/20/2004
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Hunter, Ian Warwick, David, Robert
• Granted Patent: US 7,642,096 B2
• Time in Patent Office: Days
• US Class Current: 422/51
• CPC Class Codes: G01K 1/065 of liquid column thermometers
• CPC Class Codes: G01K 17/00 Measuring quantity of heat measuring temperature by calorimetry G01K3/00 - G01K11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion G01N
• CPC Class Codes: G01K 17/006 Microcalorimeters, e.g. using silicon microstructures
• CPC Class Codes: G01K 5/02 the material being a liquid contained in a hollow body having parts which are deformable or displaceable under the pressure developed by the material G01K5/32
• CPC Class Codes: G01N 25/482 concerning the temperature responsive elements measuring temperature or quantity of heat, thermally-sensitive elements G01K; thermoelectric devices H10N10/00, H10N15/00

Abstract

A calorimeter is provided for measuring a quantity of heat. The calorimeter has a liquid constrained so as to allow expansion of the liquid solely in one dimension along a single axis such that liquid expansion may be measured on the basis of light impinging along the single axis of liquid expansion by means of a non-contact displacement transducer. Interferometric optical means for remote measurement of multiple microcalorimeters permits parallel monitoring of multiple chemical reactions and the performance of parallel biochemical assays.

Claims

1. A calorimeter for measuring a quantity of heat, the calorimeter comprising a liquid constrained so as to allow expansion of the liquid solely in one dimension along a single axis, measurement of liquid expansion being based upon light impinging along the single axis of liquid expansion.

2. A calorimeter in accordance with claim 1, further comprising a non-contact displacement transducer.

3. A calorimeter in accordance with claim 2, wherein the non-contact displacement transducer includes an optical surface displacement sensor.

4. A calorimeter in accordance with claim 3, wherein the optical surface displacement sensor includes an interferometric sensing arrangement.

5. A calorimeter in accordance with claim 3, wherein the liquid expansion is measured confocally.

6. A calorimeter in accordance with claim 3, wherein the liquid expansion is measured interferometrically in a Michelson configuration.

7. A calorimeter in accordance with claim 1, further comprising a test capillary for constraining expansion of the liquid to one dimension.

8. A calorimeter in accordance with claim 7, further comprising a control capillary, wherein the differential liquid expansion between liquid in the test capillary and liquid in the control capillary is measured interferometrically in a Mach-Zehnder configuration.

9. A calorimeter in accordance with claim 7, further comprising a control capillary, wherein the differential liquid expansion between liquid in the test capillary and liquid in the control capillary is measured interferometrically in a Michelson configuration.

10. A liquid expansion thermometer comprising:

a. a first liquid constrained so as to allow expansion of the liquid in only a single expansion dimension; and

b. an interferometer for measuring displacement of a surface of the liquid in the expansion dimension.

11. A liquid expansion thermometer in accordance with claim 10, wherein the first liquid is aqueous.

12. A liquid expansion thermometer in accordance with claim 10, further comprising a second liquid, immiscible in the first liquid, wherein the first and second liquid share an interface.

13. A system for monitoring a plurality of chemical reactions disposed in an array configuration of liquid samples, comprising a plurality of liquid expansion calorimeters, one liquid expansion calorimeter associated with each chemical reaction of the array.

14. A system for monitoring a plurality of chemical reactions, the system comprising:

a. an array of discrete reaction loci; and

b. at least one interferometer for remotely measuring a thermodynamic variable of each sample.

15. A method for monitoring heat evolved in a chemical reaction, the method comprising:

a. providing a liquid expansion calorimeter;

b. conducting heat from the chemical reaction to the liquid expansion calorimeter; and

c. monitoring a change in heat content of the liquid expansion calorimeter.

16. A method in accordance with claim 15, wherein the chemical reaction is initiated by combining two reactants on the liquid expansion calorimeter.

17. A method in accordance with claim 15, wherein a combination of the two reactants comprises an expansion liquid of the liquid expansion calorimeter.

18. A method for monitoring an array of parallel biochemical assays, the method comprising measuring a thermodynamic variable selected from the group of heat, temperature, volume, and pressure, wherein the thermodynamic variable is measured optically.

19. A method in accordance with claim 18, wherein the thermodynamic variable is measured interferometrically.

20. A method in accordance with claim 18, wherein the parallel biochemical assays are conducted within an array of microwells.