Analyte collection devices and methods

• US 20090028208A1
• Filed: 07/25/2007
• Published: 01/29/2009
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: University of Louisville
• Original Assignee: University of Louisville
• Inventors: Martin, Michael
• Granted Patent: US 8,088,341 B2
• Time in Patent Office: Days
• US Class Current: 374/1
• CPC Class Codes: G01N 1/405 by adsorption or absorption
• CPC Class Codes: G01N 2035/00366 Several different temperatures used

Abstract

An aspect of the invention is directed to a method for operating an analyte collection device of the type that includes at least one plate for storing said analyte. An example method comprises the steps of heating the at least one plate to a first temperature, taking a measurement of a property of the at least one plate, and using the measurement to estimate one or more of the amount of the analyte on the plate and the amount of contaminant on the plate.

Claims

1. A method for operating an analyte collection device of the type that includes at least one plate for storing analyte comprising the steps of:

heating said at least one plate to a first temperature;

taking a measurement of a property of said at least one plate at one or more of during the step of heating said at least one plate and after said at least one plate has been heated to said first temperature; and

,

using said measurement to estimate one or more of the amount of the analyte on said at least one plate and the amount of contaminant on said at least one plate.

2. A method for operating an analyte collection device as defined by claim 1 and:

further including the step of storing the analyte on said at least one plate before performing the step of heating said at least one plate to said first temperature;

wherein said first temperature is at least about 10°

C. above ambient;

wherein said one or more of the amount of the analyte and the contaminant on said at least one plate is the analyte; and

,

further including the step of heating said at least one plate to a second temperature to release the analyte from said at least one plate, said second temperature substantially greater than said first temperature.

3. A method for operating an analyte collection device as defined by claim 2 and further including the step of testing said analyte with an analyzer following the step of releasing said analyte.

4. A method for operating an analyte collection device as defined by claim 2 wherein the method further comprises repeating multiple iterations of the steps of claim 2 and of building a knowledge base through said iterations that is useful to predict a value for said measured property that indicates sufficient analyte has been collected for testing.

5. A method for operating an analyte collection device as defined by claim 4 wherein the step of building said knowledge base includes at least storing said measured property determined through performance of each of said iterations of the steps of claim 2, and of storing an indication of whether sufficient analyte had been collected for testing during each of said iterations.

6. A method for operating an analyte collection device as defined by claim 1 wherein:

said at least one plate comprises a plurality of plates organized in a stacked configuration, a sorbent covering at least a portion of each of said plates;

wherein the step of storing the analyte on said plate further comprises causing a fluid containing the analyte to flow past said plurality stacked plates whereby said fluid contacts said sorbent and the analyte is absorbed by said sorbent.

7. A method for operating an analyte collection device as defined by claim 1 wherein said one or more of analyte and contaminant on said at least one plate comprises contaminant, and wherein said first temperature is higher than a desorbing temperature for the analyte.

8. A method for operating an analyte collection device as defined by claim 1 wherein said measurement comprises a first measurement and further including preliminary steps of heating said at least one plate to a third temperature and taking a calibration measurement of said property of said at least one plate, and wherein the step of using said property to estimate the amount of said analyte or of said contaminant comprises comparing said first measurement to said calibration measurement.

9. A method for operating an analyte collection device as defined by claim 1 wherein the steps of heating said at least one plate to said first temperature and taking a measurement of said property comprises first heating said at least one plate to said first temperature and then measuring the temperature of said plate as said plate cools from said first temperature.

10. A method for operating an analyte collection device as defined by claim 1 wherein the steps of heating said at least one plate to said first temperature and taking a measurement of said property comprises taking said measurement while said plate is being heated to said first temperature.

11. A method for operating an analyte collection device as defined by claim 1 wherein the step of measuring said property of said at least one plate comprises measuring one or more of a thermal property and an electrical property of said at least one plate.

12. A method for operating an analyte collection device as defined by claim 1 wherein the step of measuring said property of said at least one plate comprises determining the thermal time constant T₁ for said at least one plate using the relationship:

$y=A\times <br><br>\exp <br><br>\left(\frac{-T}{T_1}\right)+y_0$

where;

y=temperature of said at least one plate, T is time, and A and y₀ are constants.

13. An analyte collection device, the device comprising:

one or more plates;

a heating element for heating said one or more plates; and

,

a controller linked to said heating element and configured to heat said heating element to a first temperature and to measure one or more properties of said at least one or more plates and to use said one or more properties to estimate the quantity of analyte collected on said at one or more plates, said controller further configured to heat said at least one or more plates to at least a second temperature that is greater than said first temperature to cause said analyte to be released from said one or more plates.

14. The device of claim 13, wherein said heating element comprises a resistive trace formed on or within said at least one or more plates, wherein said plates each have a sorbent layer thereon and wherein said one or more plates comprises a plurality of plates arranged in a stacked configuration.

15. The device of claim 13, wherein:

said heating element comprises a plurality of resistive traces formed on or within said one or more plates;

said resistive traces divide said one or more plates into a plurality of zones, one of said zones being a collection zone for collecting analyte, and another being a smaller delivery zone for concentrating analyte from the collection zone in a smaller area and delivering analyte to a detector system; and

,

said controller is configured to control each of said zones independently from others of said zones.

16. The device of claim 13 wherein said controller is further configured to:

perform a calibration by heating said one or more plates to an elevated temperature when no analyte is present and to measure at least one calibration property of said one or more plates; and

,

heat said one or more plates to a third temperature greater than said second temperature, to measure a second property of said one or more plates, and to compare said second property to said calibration value to determine if a contaminant is present on said one or more plates.

17. The device of claim 13 wherein said controller further comprise a memory, and wherein said controller is further configured to store in said memory said measured property together with data indicating whether sufficient material was present to perform a test, and wherein said controller is further configured to use said stored data to build a knowledge base over multiple tests useful to predict a minimum value for said property that indicates a sufficient quantity of said analyte is present to proceed with testing.

18. A computer program product including computer readable instructions stored on a memory medium, the program product for use with a collector device of the type that includes at least one plate for collecting analyte, the analyte released when the collector device heats the plate to a desorbing temperature, the instructions when executed by one or more computers useful to cause the collector device to:

cause the collector device plates to be heated to an elevated temperature that is substantially below the desorbing temperature;

measure a property of the plate; and

,

use the measured property to determine whether sufficient analyte has been collected to proceed with testing.

19. A computer program product as defined by claim 18 wherein the instructions when executed further cause the collector device to perform a calibration through the steps of:

heating said plates to a first elevated temperature before analyte is stored thereon;

measuring a calibration property of said plates;

storing said calibration property in a memory; and

,

wherein the instructions when causing the collector device to determine whether sufficient analyte has been collected cause the collector device to compare the measured property to the calibration property.

20. A computer program product as defined by claim 19 wherein the instructions when executed further cause the collector device to heat said plates to a temperature greater than the desorbing temperature, to measure a contamination property of said plates, and to compare said contamination property to said calibration property to determine if contaminant is present on said plates.