Breath sensor apparatus and methods of use
Breath sensor apparatus and methods of use are described herein where a flow control apparatus may generally comprise a sampling chamber defining a volume and one or more openings into the sampling chamber, at least one sensor in fluid communication with the sampling chamber, wherein the at least one sensor is configured to detect the analyte. The sampling chamber may also be configured to receive the breath sample into the sampling chamber and into contact with the at least one sensor via diffusion into the sampling chamber.
1. A method of extrapolating a final value of a parameter from a breath sample, comprising:
obtaining a calibration curve of a gas having a known parameter concentration;
recording at least a portion of the calibration curve as a function of time;
measuring an input response curve of the parameter from the breath sample via a sensor over a period of time;
associating the input response curve to the calibration curve; and
extrapolating the final value of the parameter from the breath sample when the breath sample is insufficient to reach a full signal value of the sensor such that the final value is based on the calibration curve associated with the input response curve.
2. The method of claim 1 wherein extrapolating comprises using an iterative method to determine analytical constants to achieve a best fit of an input data to a predetermined function.
3. The method of claim 1 wherein obtaining comprises obtaining the calibration curve of a gas having a known CO concentration.
4. The method of claim 1 wherein measuring comprises measuring over the period of time which is less than a time of obtaining the calibration curve.
5. The method of claim 4 wherein the period of time is less than 15 seconds.
6. The method of claim 1 wherein associating comprises applying an exponential settling function of y(t)=y terminal *(1−e −t/τ ), where:
τ=analytical function time constant
y terminal =a terminal value.
7. The method of claim 1 wherein measuring further comprises measuring the breath sample via at least one CO sensor.
8. The method of claim 7 further comprising measuring the breath sample via at least one H 2 sensor.
9. The method of claim 8 further comprising compensating for any H 2 measurement sensitivity from the at least one CO sensor with a measurement from the at least one H 2 sensor.