System and method for gas sensor that corrects for sensor poison level
A system and a method for gas sensing while correcting for a poison level of a gas sensor. The gas sensor provides first dielectric excitation of the gas sensing material at a first set of frequencies, measures responses of the gas sensing material to the first dielectric excitation while the gas sensing material is in contact with the fluid sample, provides second dielectric excitation of the gas sensing material at a second set of frequencies, measures responses of the gas sensing material to the second dielectric excitation while the gas sensing material is in contact with the fluid sample, and determines, based on the responses of the gas sensing material to the first and second dielectric excitation, identities, respective concentrations, or a combination thereof, of at least one analyte gas in a fluid sample, and a sensor poison level of the gas sensing material.
1. A gas sensor for analysis of one or more gases in a fluid sample, comprising:
a gas sensing material configured to contact the fluid sample; and
a measurement circuit operatively coupled to the gas sensing material and configured to:
provide first and second dielectric excitation of the gas sensing material at first and second respective sets of frequencies while the gas sensing material is in contact with the fluid sample;
measure responses of the gas sensing material to the first and second dielectric excitation at the first and second respective sets of frequencies while the gas sensing material is in contact with the fluid sample;
determine, based on the response of the gas sensing material to the first and second dielectric excitation at the first and second respective sets of frequencies, a poison level of the gas sensing material;
apply, based on the determined poison level and the responses of the gas sensing material to the first and second dielectric excitation at the first and second respective sets of frequencies, a transfer function configured to generate a corrected response that corrects the measured response of the gas sensing material for the poison level of the gas sensing material; and
output the corrected response.
2. The gas sensor of claim 1 , wherein the measurement circuit is configured to determine, based on the responses of the gas sensing material to the first and second dielectric excitation at the first and second respective sets of frequencies, identities, respective concentrations, or a combination thereof, of at least one analyte gas in the fluid sample.
3. The gas sensor of claim 2 , wherein the responses of the gas sensing material to the second dielectric excitation are indicative of the poison level, but not the identities and the respective concentrations of the at least one analyte gas in the fluid sample.
4. The gas sensor of claim 1 , wherein response linearity to a gas of interest is substantially maintained at a particular frequency of the first set of frequencies, independent of the poison level.
5. The gas sensor of claim 1 , wherein each frequency of the first set of frequencies is lower than each frequency of the second set of frequencies.
6. The gas sensor of claim 1 , wherein a pre-selected frequency of the first set of frequencies is selected based on the pre-selected frequency being disposed on a shoulder of a dielectric relaxation region of the gas sensing material.
7. The gas sensor of claim 1 , wherein the gas sensing material comprises a metal oxide semiconductor (MOS) sensing material.
8. The gas sensor of claim 7 , wherein the MOS sensing material is an n-type sensing material, a p-type sensing material, or a composite n-and p-type sensing material.
9. The gas sensor of claim 7 , wherein the MOS sensing material is a single-metal oxide, a perovskite oxide with two differently sized cations, or a mixed metal oxide composition.
10. The gas sensor of claim 1 , wherein the gas sensor comprises a wearable gas sensor, an ingestible gas sensor, or a tattooed gas sensor, is integrated into a mobile electronic device, is integrated into an unmanned vehicle, or is a part of a wireless sensor network.
11. The gas sensor of claim 1 , wherein the poison level is a result of the gas sensing material being exposed to a siloxane vapor.
12. The gas sensor of claim 1 , comprising:
a heating element coupled to the gas sensing material and configured to heat the gas sensing material; and
a heating element controller operatively coupled to the heating element and configured to control the heating element to heat the gas sensing material.
13. A method of operating a gas sensor, comprising:
exposing a gas sensing material of the gas sensor to a fluid sample;
providing, via an impedance detector operatively coupled to the gas sensing material, first dielectric excitation of the gas sensing material at a first set of frequencies;
measuring responses of the gas sensing material to the first dielectric excitation at the first set of frequencies while the gas sensing material is in contact with the fluid sample;
providing, via the impedance detector, second dielectric excitation of the gas sensing material at a second set of frequencies;
measuring responses of the gas sensing material to the second dielectric excitation at the second set of frequencies while the gas sensing material in contact with the fluid sample; and
determining, based on the responses of the gas sensing material to the first and second dielectric excitation at the first and second set of frequencies, identities, respective concentrations, or a combination thereof, of at least one analyte gas of the fluid sample, and a sensor poison level of the gas sensing material.
14. The method of claim 13 , comprising:
identifying one or more frequencies of the first set of frequencies at which the response of the gas sensing material to the first dielectric excitation is substantially linear; and
applying a transfer function to data collected from the response of the gas sensing material to the first dielectric excitation at the one or more frequencies of the first set of frequencies and to the second dielectric excitation at the one or more frequencies of the second set of frequencies to generate corrected response data that corrects for the sensor poison level.
15. The method of claim 14 , wherein the responses of the gas sensing material to the at least one analyte gas are indiscernible at the second set of frequencies.
16. The method of claim 14 , wherein the transfer function is based on real and imaginary parts of an impedance spectra at the first and second sets of frequencies.
17. A method of calibrating a gas sensor, comprising:
obtaining first responses of the gas sensor to first dielectric excitation at a first frequency range while the gas sensor is in contact with a range of known concentrations of a gas, wherein the first responses of the gas sensor over the range of known concentrations of the gas are substantially linear;
relating the first responses of the gas sensor to the range of known concentrations of the gas;
computing one or more analytical fit coefficients between the first responses and the range of known concentrations of the gas, wherein the one or more analytical fit coefficients correct for a poison level of the gas sensor;
storing the one or more analytical fit coefficients on an on-board memory, accessible by an on-board processor;
obtaining second responses of the gas sensor to second dielectric excitation at a second frequency range while the gas sensor is in contact with an unknown concentration of the gas; and
determining, based on the second responses of the gas sensor, and the one or more analytical fit coefficients, the unknown concentration of the gas.
18. The method of claim 17 , comprising:
providing the first and second dielectric excitation of the gas sensor at the first and second respective frequency ranges while the gas sensing material is in contact with a fluid sample that includes the gas; and
measuring the first and second responses of the gas sensor to the first and second dielectric excitation at the first and second frequency ranges while the gas sensing material is in contact with the fluid sample that includes the gas.
19. The method of claim 17 , wherein determining, based on the second responses of the gas sensor, and the one or more analytical fit coefficients, the unknown concentration of the gas comprises applying a transfer function to the second responses of the gas sensor to the second dielectric excitation at the second frequency range, wherein the transfer function is based on the stored one or more analytical fit coefficients and is configured to correct for the poison level of the gas sensor.
20. The method of claim 19 , wherein the transfer function is based on real and imaginary parts of an impedance spectra at the first frequency range, the second frequency range, or both.