Methods for detecting and quantifying gas species analytes using differential gas species diffusion
Inventors
Savoy, Steve M. • Hoover, Kyle W. • Mitchell, Daniel R. • John, Jeremy J. • Mann, Chris W. • Greis, Alexander P.
Assignees
Publication Number
US-11988662-B2
Publication Date
2024-05-21
Expiration Date
2036-12-07
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Abstract
Methods and sensors for the detection, identification, and quantification of one or more gas species, including volatile organic compounds, in a test sample are described. Methods employ gas sensors comprising a diffusion matrix present on the sensor surface. A gas analyte in a test sample diffuses through the matrix and is detected upon interaction of the analyte with the sensor. A response profile of a gas sensor to a gas analyte in the test sample is compared to a control gas sensor response profile determined in a similar manner for a known gas species. Comparisons of test sample and control sample sensor response profiles enable detection, identification, and quantification of a gas species analyte in a test sample.
Core Innovation
The invention provides methods and sensors for the detection, identification, and quantification of one or more gas species, including volatile organic compounds, in a test sample using gas sensors with a diffusion matrix present on the sensor surface. When a gas analyte in a test sample diffuses through the matrix and interacts with the sensor, the resulting sensor response profile is recorded. These response profiles are compared to control profiles determined in a similar way for known gas species. By analyzing differences and similarities between test and control profiles, the presence, identity, and amount of a gas species analyte in a sample can be determined.
The invention addresses the limitations of current gas detection methods that often require bulky instrumentation, vacuum chambers, and high power consumption. Existing gas nanosensors lack selectivity and detect most or all gas species that bind to the surface, making it difficult to distinguish between different analytes. The invention overcomes these issues by employing a diffusion matrix—comprising molecules, molecular compounds, or biomolecules—on the sensor surface to alter the diffusion rate of analytes, resulting in unique sensor response profiles for different gases and matrix types.
Comparisons of sensor response profiles from sensors derivatized with different diffusion matrices, or between derivatized and underivatized sensors, enable improved specificity. The methodology allows for multiple gas species to be queried using arrays of sensors, each with different diffusion matrices, and supports application to gases present in test samples of various forms, including solids, liquids, vapor phases, or biological and environmental samples. The approach leverages predictable changes in diffusion and adsorption kinetics to provide accurate detection and quantification of gas analytes.
Claims Coverage
The patent includes two independent claims describing a method for determining the presence of one or more gas species analytes in a test gas sample using a sensor array with diffusion matrices.
Determination of gas species using sensor arrays with differing diffusion matrices
A method that exposes a plurality of gas sensors (of the same type) to a test gas sample, where the sensors comprise either: - a sensor derivatized with a first type of diffusion matrix, - a sensor derivatized with a second type of diffusion matrix, - or a sensor derivatized with a diffusion matrix and a sensor lacking a diffusion matrix. The diffusion matrices comprise one or more molecules, molecular compounds, or ionic compounds selected to interact non-specifically with the gas analyte during diffusion to and from the sensors. The method includes stopping gas exposure, determining sensor response profiles from a selected time before to after exposure, and comparing the test sample sensor response profiles with corresponding control profiles (determined under similar matrix and sensor conditions). The presence of the selected gas species analyte is determined based on observed differences or similarities. Further features allow for: - comparison with control profiles stored in a database, - use of read-out integrated circuits and analysis algorithms, - quantification and ratiometric comparison, - selection of biomolecules as diffusion matrices, - application to various types of test samples (gas, liquid, biological, or environmental), - the sensors being arranged in an array and possibly fabricated by nanoimprint lithography.
Determination of multiple gas species using multiple diffusion matrices
A method that determines the presence of a plurality of selected different gas species analytes in a test gas sample by exposing a plurality of sensors, each derivatized with different types of diffusion matrices or lacking a diffusion matrix, to the test sample. The method comprises the same steps as in the first inventive feature (expose, stop exposure, determine and compare response profiles, compare to control profiles), but with the focus on detecting more than one gas species analyte based on the differences or similarities in response profiles. Additional features include storing control profiles in a database, use of read-out circuits and data analysis algorithms, and quantification using deconvolution approaches.
The inventive features of the claims are centered on methods for detecting and quantifying one or more gas species analytes using sensor arrays with variation in diffusion matrices and profile comparison approaches, enabling specificity and multiplexed measurements in a range of sample contexts.
Stated Advantages
The methods provide improved accuracy and specificity in gas analyte detection and identification, even in the presence of multiple analytes.
The approach allows for rapid and high sensitivity detection times for gas analytes.
It enables the detection, identification, and quantification of gas species in various sample types, including gases, liquids, solids, biological and environmental samples.
The use of diffusion matrices and corresponding response profiles enhances the capability to distinguish between different gas species and their concentrations.
Multiplexed querying of multiple analytes is achievable using arrays of sensors with different diffusion matrices.
The described sensors and arrays support real-time or near real-time detection without need for bulky instruments or high power consumption.
Documented Applications
Evaluating air samples for the presence of hazardous gases or determining safety of air samples for human respiration.
Monitoring gas production, solvent evaporation, reaction progress, and end-product yield during industrial chemical production and petrochemical refining.
Characterizing human-specific volatile organic compounds (e.g., in breath samples) for evaluating various health factors, diagnosing conditions or diseases, determining identity, and examining performance factors such as stress or fatigue.
Detecting gas species analytes in a broad range of samples including biological, environmental, medical, pharmaceutical, manufacturing, and chemical process samples.
Collecting biological threat samples by military or first responders.
Sampling ambient air around an object or subject to determine or identify recent human activity.
Sampling ambient air to detect presence of a human or organism or identifying a specific biological odor profile.
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