Method for Monitoring the Thermal Coupling of a Measuring Cell

• US 20100158070A1
• Filed: 12/10/2009
• Published: 06/24/2010
• Est. Priority Date: 12/18/2008
• Status: Active Grant

• Current Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Walla, Juergen, Schneider, Friedrich, Kraker, Michael, Steinboeck, Wolf-Dietrich, Felsberger, Robert
• Granted Patent: US 8,491,185 B2
• Time in Patent Office: Days
• US Class Current: 374/44
• CPC Class Codes: G01N 33/4925 measuring blood gas content, e.g. O2, CO2 , HCO3

Abstract

A method for checking the quality of thermal coupling between a measuring cell and a thermostatted element of an analyzer, where the measuring cell can be exchangeably inserted into an analyzer to measure at least one parameter of a sample, and is provided with at least one sensor element in a measuring channel.

Claims

1. A method for checking a quality of a thermal coupling between a measuring cell and a thermostatted element of an analyzer, the measuring cell being exchangeably insertable into the analyzer to measure at least one parameter of a sample, and being provided with at least one sensor element in a measuring channel, comprising:

(a) establishing mechanical contact with between the measuring cell and the thermostatted element;

(b) filling the measuring channel with a fluid,

(c) equilibrating the temperature between the measuring channel and the fluid;

(d) applying a rapid temperature change using the thermostatted element;

(e) measuring over time a signal curve of the at least one sensor element after the rapid temperature change has been applied; and

(f) determining the quality of the thermal coupling by analyzing the signal curve over time resulting from the measurements of step (e).

2. The method of claim 1, wherein the fluid is selected from a calibrating fluid, a rinsing fluid, a sample fluid and a quality control fluid.

3. The method of claim 1, wherein the at least one sensor element is used for measuring the signal curve.

4. The method of claim 1, wherein the signal curve of a temperature-dependent property of the fluid is measured.

5. The method of claim 1, wherein the signal curve of conductivity, resistance, or impedance of the fluid is measured.

6. The method of claim 5, wherein a maximum difference D between a normalized temperature curve of the thermostatted element and a normalized conductivity, resistance or impedance curve is determined, and the quality of the thermal coupling is evaluated using a preselected threshold value for the maximum difference D.

7. The method of claim 5, wherein a quotient Q of a slope of a temperature curve of the thermostatted element and of a slope of a conductivity, resistance, or impedance curve of an operational fluid are determined and the quality of the thermal coupling is evaluated using a preselected threshold value for the quotient Q.

8. The method of claim 1, wherein the at least one sensor is a temperature dependent sensor, a chemical sensor or an optical sensor.

9. The method of claim 8, wherein the at least sensor is an electrochemical sensor or an optical sensor element for determination of anions or cations.

10. The method of claim 9 wherein the cations are selected from Li⁺, Na⁺, K⁺, Mg⁺⁺, and Ca⁺⁺.

11. The method of claim 9, where in the anions are Cl⁻

.

12. The method of claim 1, wherein the at least one sensor element is used for the determination of biochemical substances.

13. The method of claim 1, wherein the at least one sensor measures dissolved gases or pH value.

14. The method of claim 8, wherein the maximum difference D between the normalized temperature curve of the thermostatted element and a normalized signal curve of the electrochemical or the optical sensor element is computed, and the quality of thermal coupling is evaluated using the preselected threshold value for the maximum difference D.

15. The method of claim 8, wherein the quotient Q of the slope of the temperature curve of the thermostatted element and a slope of a measurement signal curve of the electrochemical or optical sensor element measured over time is computed, and the quality of the thermal coupling is evaluated using the preselected threshold value for the quotient Q.