Methods and apparatuses for determining concentration of target gas in sample gas

Abstract

To provide methods, apparatuses, and systems for determining concentration of a target gas in a sample gas.SOLUTION: An example method of preparing a replaceable testing material for detecting a target gas in a sample gas may include: preparing a solution comprising a solute and a solvent, the solute containing o-tolidine; introducing a testing material substrate to the prepared solution for a period of time; and removing at least a portion of the solvent from the testing material substrate such that the testing material substrate contains at least a portion of the o-tolidine, and thereby forming the replaceable testing material for detecting the target gas in the sample gas.SELECTED DRAWING: None

Description

[Technical field]

[0001] Embodiments of the present disclosure relate generally to determining the concentration of a target gas in a sample gas, and more specifically, to determining the concentration of nitric oxide (NO) in a sample gas using replaceable test materials in a care or medical environment. [Background technology]

[0002] Applicant has identified numerous deficiencies and technical problems associated with conventional systems, apparatus, and methods for determining the concentration of a target gas in a sample gas, particularly in a medical environment. Through exerted effort, ingenuity, and innovation, many of these identified problems have been resolved by developing solutions contained in embodiments of the present disclosure, examples of which are numerously described in detail herein. Summary of the Invention

[0003] In general, various embodiments of the present disclosure provided herein may provide solutions to problems and needs in the art that have not yet been fully identified, recognized, or resolved by current techniques for determining the concentration of a target gas in a sample gas. According to some embodiments of the present disclosure, an exemplary method of preparing an exchangeable test material for determining the concentration of a target gas in a sample gas is provided. In some embodiments, the method may include preparing a solution including a solute and a solvent, the solute including o-tolidine, introducing a test material substrate into the prepared solution for a period of time, and removing at least a portion of the solvent from the test material substrate such that the test material substrate includes at least a portion of o-tolidine, thereby forming an exchangeable test material for determining the concentration of a target gas in a sample gas.

[0004] In some embodiments, removing at least a portion of the solvent from the test material substrate may include evaporating the solvent (e.g., ethanol). In some embodiments, removing at least a portion of the solvent from the test material substrate may include applying absorbent paper to the test material substrate. In some further embodiments, removing at least a portion of the solvent from the test material substrate may include exposing the test material substrate to a stream of nitrogen gas.

[0005] In some embodiments, the solvent may include ethanol, hi some further embodiments, the solvent may include water.

[0006] In some embodiments, the period during which the test material substrate is introduced into the prepared solution may be a minimum of about 30 seconds.

[0007] In some embodiments, the test material substrate comprises a slow test strip.

[0008] According to some embodiments of the present disclosure, there is further provided an exemplary method for determining a concentration of a target gas in a sample gas. In some embodiments, the method may include contacting a replaceable test material with a sample gas, where at least a portion of the sample gas is the target gas, and the replaceable test material includes o-tolidine, identifying a color of the replaceable test material, and determining a concentration of the target gas in the sample gas based at least in part on the identified color of the replaceable test material.

[0009] In some embodiments, determining the concentration of the target gas in the sample gas may include determining a concentration of an oxidized derivative of the target gas and correlating the determined concentration of the oxidized derivative to the concentration of the target gas, hi some further embodiments, the target gas is nitric oxide and the oxidized derivative is nitrogen dioxide.

[0010] In some embodiments, contacting the replaceable test material with the sample gas may include exposing the replaceable test material to a sample gas stream. In some further embodiments, the replaceable test material is disposed within a gas detection device, and exposing the replaceable test material to a sample gas stream may include directing the sample gas stream toward the replaceable test material within the gas detection device. In some further embodiments, the sample gas may include a target gas, and after contacting the replaceable test material with the sample gas, the replaceable test material changes color based at least in part on the presence of the target gas. In further embodiments, the identified color of the replaceable test material may be blue, green, or a combination thereof.

[0011] According to some embodiments of the present disclosure, an exemplary reusable gas detection device for determining a concentration of a target gas in a sample gas is provided. In some embodiments, the exemplary reusable gas detection device may include a replaceable test material configured to change color based at least in part on the presence of the target gas in the sample gas or an oxidized derivative of the target gas in the sample gas, the replaceable test material including o-tolidine, and a controller configured to determine the concentration of the target gas.

[0012] In some embodiments, the reusable gas detection apparatus may further include an imaging device, and the controller may be configured to determine the concentration of the target gas based at least in part on correlating a color of the replaceable test material in one or more images of the replaceable test material captured by the imaging device to the concentration of the target gas.

[0013] In some embodiments, the controller may be configured to determine a concentration of the target gas based at least in part on determining a concentration of an oxidized derivative of the target gas.

[0014] In some embodiments, the reusable gas detection device may include an oxidation chamber containing an oxidizer that oxidizes at least a portion of the target gas in the sample gas to an oxidized derivative of the target gas before the sample gas reaches the replaceable test material. In some further embodiments, the target gas is nitric oxide and the oxidized derivative is nitrogen dioxide. In still further embodiments, the reusable gas detection device may include an integral display configured to present the result of the determined concentration of nitric oxide in the sample gas. [Brief description of the drawings]

[0015] Having thus described the disclosure in general terms, reference is now made to the accompanying drawings, which are not necessarily drawn to scale. Components illustrated in the figures may or may not be present in a particular embodiment described herein. Some embodiments may include fewer (or more) components than shown in the figures in accordance with exemplary embodiments of the present disclosure.

[0016] [Figure 1] 1 is an exploded view of an exemplary gas detection apparatus, according to certain exemplary embodiments described herein. [Diagram 2] FIG. 1 is a schematic block diagram illustrating example components of a color meter reader, according to certain example embodiments described herein. [Diagram 3] FIG. 2 is a schematic block diagram illustrating example components of a controller, according to certain example embodiments described herein. [Figure 4] 1 is a flow chart illustrating an example method of preparing a replaceable test material for determining a concentration of a target gas in a sample gas, according to certain example embodiments described herein. [Diagram 5] 4 is a flow chart illustrating an example method for determining a concentration of a target gas in a sample gas, according to certain example embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Exemplary embodiments of the present disclosure will now be described in more detail below with reference to the accompanying drawings, which illustrate some, but not all, embodiments of the present disclosure. Indeed, embodiments of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0018] Various exemplary embodiments address technical problems associated with determining the concentration of a target gas contained in a sample gas. As will be understood by those skilled in the art to which this disclosure pertains, there are numerous exemplary scenarios in which a user may seek to determine the concentration of a target gas in a sample gas. For example, there are numerous environmental and health-related situations in which it may be desirable or necessary to determine the concentration of a target gas, such as nitric oxide (NO), in a sample gas. However, due to rapid chemical reactions with a wide range of molecules, some target gases, such as nitric oxide, may be particularly difficult to measure, especially in medical situations.

[0019] The use of nitric oxide in various medical procedures is widespread. The presence of nitric oxide in biological materials has been associated with various beneficial effects in health situations, particularly due to the effects that nitric oxide has at the cellular level. For example, nitric oxide is utilized in wound healing therapy to achieve improved inflammatory responses to damaged cells, cell proliferation and re-growth, new blood vessel formation through collagen formation, and prevention of microbial colonization. Nitric oxide has also been shown to exhibit improved anti-cancer activity in the body. In addition, nitric oxide is utilized in respiratory and cardiovascular applications, showing improvements in the functioning of these body systems. Significant research continues to be conducted to develop and evaluate nitric oxide donors, such as dendrimers, metal-organic frameworks (MOFs), micelles, inorganic nanoparticles (NPs), and gels, that are used to deliver nitric oxide to various biological systems that can benefit from increased nitric oxide. Due to the numerous physiological and pathological benefits of nitric oxide, modulation of nitric oxide levels in various tissues may have significant therapeutic value. Furthermore, regulation of nitric oxide levels may entail accurate measurement of nitric oxide in various sample gases.

[0020] Many exemplary methods for measuring nitric oxide are expensive, inaccurate, unreliable, not suitable for medical or point-of-care applications, and / or difficult to administer. Chemiluminescence utilizes the chemiluminescent properties of nitric oxide when reacted with, for example, ozone, to determine the amount of nitric oxide in a particular substance based on the light output. Although chemiluminescence may be commonly used in laboratory and / or hospital environments, the cost of chemiluminescence may be prohibitively high, and as a result, the use of chemiluminescence technology may be limited to research settings, such as large hospitals and universities. Furthermore, the long detection times and complex process may require highly trained operators to perform the tests. Furthermore, the detection system must be periodically calibrated to obtain accurate results.

[0021] Gas chromatography can use analytical chemistry to separate and analyze compounds that can be evaporated without decomposition. Gas chromatography may be more suitable for laboratory, environmental, and / or industrial applications, and is not easily performed on individuals or patients in a healthcare environment. In addition, gas chromatography can be cost prohibitive, and like chemiluminescence, the long detection times and complex process may require highly trained operators to perform the test. Furthermore, the detection system must be calibrated periodically to obtain accurate results.

[0022] Electrochemical sensors can generate current from energy released by spontaneous redox reactions. However, electrochemical sensors can be difficult to calibrate and operate, and may require highly trained operators to manage the testing process. In addition, the cost of detecting nitric oxide using electrochemical sensors can be significant.

[0023] Spectral absorption can use spectroscopic techniques to measure the absorption of radiation as a function of the frequency of the wavelength of the incident light. The interaction of the incident light with the sample gas can detect the concentration of nitric oxide. However, spectral absorption may be more suitable for laboratory and / or environmental applications and is not easy to perform on individuals or patients in a healthcare environment. In addition, the test duration of spectral absorption may be long. Furthermore, the cost per test to perform spectral absorption may be prohibitively high, and the test execution process may be complex, requiring highly trained operators to perform the tests and periodically calibrate the test equipment.

[0024] Various embodiments of the present disclosure provide methods and devices for determining the concentration of a target gas, such as nitric oxide, in a sample gas. The inventors have determined that it would be desirable and advantageous to be able to more easily and efficiently determine the concentration of nitric oxide in a sample gas. As a result of the exemplary embodiments and some examples described herein, the effectiveness and ease of use of a gas detection device capable of detecting nitric oxide can be significantly improved. For example, in some embodiments, the gas detection device may be reusable, but the measurement components of the gas detection device (e.g., replaceable test material) may be disposable (i.e., replaceable) such that the test material is used only once, reducing the possibility of exposing the patient to any possible contamination from a previous patient. Furthermore, the cost per test of the sample gas can be lowered as a result of the replaceable test material, and the replaceable test material may not require periodic calibration for accurate operation due to previous use. These characteristics as well as additional features, functions, and details are described below. Similarly, corresponding and additional embodiments are also described below.

[0025] Exemplary Apparatus of the Disclosure The replaceable test material 105 of the present disclosure can be used in various gas detection devices, not limited to the gas detection devices described herein. Referring now to FIG. 1, an exemplary gas detection device 100 is shown according to one exemplary embodiment. As shown in FIG. 1, the exemplary gas detection device 100 can be configured to receive a sample gas 150, for example, via a gas inlet 101. The gas inlet 101 can be any hose, tube, nozzle, or similar structure configured to receive the sample gas 150 from a gas source. The sample gas 150 can be any gas, fluid, and / or substance received from any such gas source. For example, the sample gas 150 can be received from a subject, such as a human subject, an environment, a machine, a cavity, a space, or other biological or environmental source. The source can be direct (e.g., by a subject exhaling directly into the gas inlet 101) or indirect (e.g., from a sample bag). The sample gas 150 can be composed of multiple gases and molecules.

[0026] In some embodiments, the sample gas 150 may potentially include a target gas 160A. The target gas 160A may include any gas, fluid, and / or substance from any source. The target gas 160A may be one or more gases that the gas detection apparatus 100 is configured to detect. For example, in some embodiments, the target gas 160A may be nitric oxide (NO). The target gas 160A may constitute a gas concentration in the sample gas 150. A gas concentration refers to the amount (e.g., mass, atoms, molecules, moles) of a gas present in a particular volume at a particular time. The gas concentration of the target gas 160A may be measured as a ratio of the number of particles of the target gas 160A to the total number of particles in the sample gas 150. In some embodiments, the concentration measurement may be expressed as a ratio, such as parts per million (ppm) or parts per billion (ppb). In some embodiments, the replaceable test material 105 can be used to detect concentrations of the target gas 160A and / or the oxidized derivatives 160B of the target gas as low as 5 ppb.

[0027] As shown in FIG. 1, an exemplary gas detection apparatus 100 may include a replaceable test material 105. While the gas detection apparatus 100 itself may be reusable, the replaceable test material 105 is configured to be a consumable item (e.g., a one-time use, disposable, replaceable component). As shown in FIG. 1, the replaceable test material 105 may be disposed within the gas detection apparatus 100, for example, within the flow of the sample gas 150 (e.g., the sample gas stream). The replaceable test material 105 may include any material configured to react with a stimulus (e.g., the target gas 160A or its oxidized derivative 160B) such that the color of the replaceable test material 105 changes when the replaceable test material 105 is exposed to the stimulus. In such an embodiment, the replaceable test material 105 is a colorimetric indicator of the presence of the stimulus (e.g., nitric oxide or any oxidized derivative such as nitrogen dioxide (NO2)). In other words, in some embodiments, the color and / or shade of the exchangeable test material 105 may be indicative of the concentration of the target gas 160A (e.g., or its oxidized derivative 160B) in the sample gas 150. For example, in some embodiments, the darker the shade of the color, the higher the concentration of the target gas 160A or its oxidized derivative 160B. For example, in some embodiments, different shades of blue, green, and / or blue-green may indicate different concentrations of the target gas 160A or its oxidized derivative 160B. Or, for example, in some embodiments, yellow may indicate a low concentration and red may indicate a high concentration, with the different colors being based on various concentration ranges. Placing the exchangeable test material 105 near or in the sample gas flow may provide a more accurate measurement of the concentration of the target gas 160A or its oxidized derivative 160B in the sample gas 150. An exemplary method of preparing the exchangeable test material 105 for determining the concentration of the target gas 160A in the sample gas 150 is further described in connection with FIG. 4.

[0028] As further shown in FIG. 1 , the exemplary gas detection apparatus 100 may include a color meter reader 200. The color meter reader 200 may be any device comprising a sensing element and a computing component configured to determine a concentration of the target gas 160A and / or an oxidized derivative 160B of the target gas in the sample gas 150 based on measurements derived from the replaceable test material 105. For example, an exemplary block diagram of the exemplary color meter reader 200 is provided in FIG. 2. As shown in FIG. 2 , the color meter reader 200 may comprise an imaging device 215. The imaging device 215 may be any device, module, or other apparatus configured to capture image data (e.g., one or more images of the replaceable test material 105). The imaging device 215 may comprise a lens, an image sensor (e.g., a charge-coupled device sensor, a complementary metal-oxide semiconductor sensor), and / or a communication circuit. In some embodiments, the imaging device 215 may be instructed to capture image data of the replaceable test material 105. In some embodiments, the image sensor may be configured to capture color images, thereby enabling the gas detection apparatus 100 to determine the concentration of the target gas 160A and / or oxidized derivatives 160B of the target gas in the sample gas 150 based at least in part on the color of the replaceable test material 105. In some embodiments, the imaging device 215 may include an on-board processor that supports, among other things, image processing functions.

[0029] 2, the imaging device 215 may be electrically and communicatively connected to the controller 210, thereby enabling the imaging device 215 to transmit captured image data to the controller 210 for further processing. Changes in color of the replaceable test material 105 may be monitored and / or identified by the controller 210, as will be further described in connection with FIG. 5. For example, based at least in part on images received from the imaging device 215, the controller 210 of the color meter reader 200 may determine the concentration of the target gas 160A and / or the oxidized derivative 160B of the target gas in the sample gas 150. An exemplary controller 210 is further described in connection with FIG. 3.

[0030] Returning to FIG. 1, the exemplary gas detection apparatus 100 may include an oxidation chamber 115. In some embodiments, the oxidation chamber 115 may be disposed within the gas inlet 101 of the gas detection apparatus 100 as shown in FIG. 1. The oxidation chamber 115 may include one or more gas filters 116. The gas filter 116 may be comprised of any material, structure, or device, or combination of materials, structures, or devices, configured to allow the sample gas 150 to pass while substantially removing volatile organic compound (VOC) molecules and / or moisture contained within the sample gas 150. Non-limiting examples of the gas filter 116 may include cellulose acetate, polypropylene, paper, cotton, charcoal, cork, and other permeable materials. In some embodiments, a combination of materials may be utilized as the gas filter 116, for example, a first material may be utilized to remove VOCs and a second material may be utilized to remove moisture from the sample gas 150.

[0031] As further shown in FIG. 1, the exemplary oxidation chamber 115 of the gas detection apparatus 100 may include an oxidizer 120. For example, as shown in FIG. 1, a first gas filter 116 may be disposed near a proximal end of the oxidation chamber 115, a second gas filter 116 may be disposed near a terminal end of the oxidation chamber 115, and an oxidizer 120 may be disposed therebetween. The oxidizer 120 may be any chemical, compound, material, or other substance that can easily transfer oxygen atoms to a target gas 160A in the sample gas 150. That is, the oxidizer 120 oxidizes at least a portion of the target gas 160A in the sample gas 150 to an oxidized derivative 160B of the target gas before the sample gas 150 reaches the exchangeable test material 105 disposed in the gas detection apparatus 100. For example, when nitric oxide is the target gas 160A, the oxidizer 120 may be, for example, a metal oxide compound or potassium permanganate (KMnO4). The oxidizing agent can transfer oxygen atoms to nitric oxide molecules as they pass through the oxidation chamber 115. In some embodiments, such oxidation results in an oxidized derivative, nitrogen oxide (NO2). Nitrogen dioxide may be more stable than nitric oxide and less susceptible to reaction with other chemical molecules. Thus, measuring the concentration of the resulting nitrogen dioxide may provide an easier and more accurate representation of the amount of nitric oxide in the sample gas 150 than attempting to measure the concentration of nitric oxide directly.

[0032] As further shown in FIG. 1 , the exemplary gas detection device 100 may optionally include a housing 102 configured to receive a sample gas 150 via a gas inlet 101 and direct a flow of the sample gas 150 (e.g., a sample gas stream) toward a replaceable test material 105. The optional housing 102 may also be configured to receive and / or attach to a cover 103. A cover ring 104 (e.g., an O-ring) may surround an outer edge of the cover 103 to form an airtight seal between the cover 103 and a wall of the housing 102. The cover 103 may include a gas outlet opening 116 and a cover opening 114, the gas outlet opening 116 being positioned to receive the sample gas flow from the housing 102 and direct the sample gas flow to exit through the cover opening 114 positioned opposite the gas outlet opening 116. Cover opening 114 may optionally be further configured to receive additional components such as replaceable test material 105, pressure stem 110 (e.g., to control gas flow), gas outlet ring 108 (e.g., an O-ring that forms an airtight seal between pressure stem 110 and gas outlet opening 116), and lock 109 (e.g., to apply pressure to cover 103 to ensure an airtight seal). Housing 102 may also be configured to provide a mounting location for color meter reader 200 (e.g., including one or more latching mechanisms such as locks, latches, screws, or other mechanisms) such that a sensing device within color meter reader 200 can monitor replaceable test material 105 during operation.

[0033] 3, an example controller 210 is disclosed in accordance with at least some example embodiments of the present disclosure. The controller 210 comprises a processor 301, input / output circuitry 302, memory 303, communication circuitry 304, imaging device interface circuitry 305, and image processing circuitry 306. In some embodiments, the controller 210 is configured to use one or more of the sets of circuits 301, 302, 303, 304, 305, and / or 306 to execute and perform the operations described herein.

[0034] Although the components are described in terms of functional limitations, it should be understood that a particular implementation necessarily involves the use of specific computing hardware. It should also be understood that in some embodiments, some of the components described herein include similar or common hardware. For example, two sets of circuits both leverage the use of the same processor(s), network interface(s), storage medium(s), etc. to perform their associated functions, so that duplicate hardware is not required for each set of circuits. Thus, users of the term "circuitry" as used herein with respect to components of the apparatus described herein should be understood to include specific hardware configured to perform the functions associated with the specific circuitry described herein.

[0035] In particular, the term "circuitry" should be broadly understood to include hardware and, in some embodiments, software for configuring hardware. For example, in some embodiments, "circuitry" includes processing circuitry, storage media, network interfaces, input / output devices, etc. Alternatively or additionally, in some embodiments, other elements of controller 301 provide or complement the functionality of other particular sets of circuits. For example, in some embodiments, processor 301 provides processing functionality for any of the sets of circuits, memory 303 provides storage functionality for any of the sets of circuits, communication circuitry 304 provides network interface functionality for any of the sets of circuits, etc.

[0036] In some embodiments, the processor 301 (and / or a co-processor, or any other processing circuitry that assists or is otherwise associated with the processor) communicates with the memory 303 via a bus for passing information between components of the controller 210. In some embodiments, for example, the memory 303 is non-transitory and may include, for example, one or more volatile and / or non-volatile memories. In other words, for example, in some embodiments, the memory 303 includes or embodies an electronic storage device (e.g., a computer-readable storage medium). In some embodiments, the memory 303 is configured to store information, data, content, applications, instructions, etc. to enable the controller 210 to perform various functions according to exemplary embodiments of the present disclosure.

[0037] Processor 301 may be embodied in a number of different ways. For example, in some exemplary embodiments, processor 301 includes one or more processing devices configured to function independently. Additionally or alternatively, in some embodiments, processor 301 includes one or more processor(s) configured in tandem via a bus to enable independent instruction execution, pipelining, and / or multithreading. Use of the term "processor" or "processing circuitry" should be understood to include a single-core processor, a multi-core processor, multiple processors internal to controller 210, and / or one or more remote or "cloud" processor(s) external to controller 210.

[0038] In an exemplary embodiment, the processor 301 is configured to execute instructions stored in the memory 303 or otherwise accessible to the processor. Alternatively or additionally, in some embodiments, the processor 301 is configured to execute hard-coded functions. Thus, whether configured by hardware methods, software methods, or a combination thereof, the processor 301 represents an entity (e.g., physically embodied in a circuit) capable of performing operations according to embodiments of the present disclosure while configured accordingly. Alternatively or additionally, as another example in some exemplary embodiments, when the processor 301 is embodied as an execution body of software instructions, the instructions specifically configure the processor 301 to perform algorithms embodied in specific operations described herein when such instructions are executed.

[0039] As a particular exemplary embodiment, the processor 301 is configured to perform various operations related to utilizing various sensors and devices to determine the concentration of the target gas 160A in the sample gas (e.g., the sample gas 150). In some embodiments, the processor 301 includes hardware, software, firmware, and / or a combination thereof to receive an image of a test material (e.g., the replaceable test material 105) from an imaging device (e.g., the imaging device 215), the test material being disposed in the sample gas stream, and the color of the test material being correlated with the concentration of the target gas (e.g., the target gas 160A and / or its oxidized derivative 160B). Additionally or alternatively, in some embodiments, the processor 301 includes hardware, software, firmware, and / or a combination thereof to determine the concentration of the target gas 160A and / or its oxidized derivative 160B based at least in part on the color of the test material (e.g., the replaceable test material 105).

[0040] In some embodiments, the controller 210 includes input / output circuitry 302 that provides output to a user and, in some embodiments, receives indications of user input. In some embodiments, the input / output circuitry 302 communicates with the processor 301 to provide such functionality. The input / output circuitry 302 may include one or more user interface(s) (e.g., user interfaces), and in some embodiments includes a display with the interface(s) rendered as a web user interface, an application user interface, a user device, a back-end system, etc. The processor 301 and / or the input / output circuitry 302 including the processor may be configured to control one or more functions of one or more user interface elements via computer program instructions (e.g., software and / or firmware) stored on a memory accessible to the processor (e.g., memory 303, etc.). In some embodiments, the input / output circuitry 302 includes or utilizes user-facing applications to provide input / output functionality to client devices and / or other displays associated with the user.

[0041] In some embodiments, the controller 210 includes a communication circuit 304. The communication circuit 304 includes any means, such as a device or circuit embodied in either hardware or a combination of hardware and software, configured to transmit and receive data to and from a network and / or any other device, circuit, or module in communication with the controller 210. In this regard, the communication circuit 304 includes, for example, in some embodiments, a network interface for enabling communication with a wired or wireless communication network. Additionally or alternatively, in some embodiments, the communication circuit 304 includes one or more network interface card(s), antenna(s), bus(es), switch(es), router(s), modem(s), and supporting hardware, firmware, and / or software, or any other device suitable for enabling communication over one or more communication network(s). Additionally or alternatively, the communication circuit 304 includes circuitry for interacting with an antenna and / or other hardware or software to cause transmission of signals via the antenna(s) or control reception of signals received via the antenna(s). In some embodiments, the communications circuitry 304 allows data to be sent to and received from client devices in communication with the controller 210 .

[0042] The imaging device interface circuit 305 includes hardware, software, firmware, and / or combinations thereof that support various functions associated with command and control of an imaging device (e.g., imaging device 215) of a color meter reader (e.g., color meter reader 200). For example, in some embodiments, the imaging device interface circuit 305 includes hardware, software, firmware, and / or combinations thereof that receive, decode, and / or otherwise process or pre-process captured image data. Additionally or alternatively, in some embodiments, the imaging device interface circuit 305 includes hardware, software, firmware, and / or combinations thereof that store and / or otherwise cache image data for later use, retrieval, transmission, and / or other processing. In some embodiments, the imaging device interface circuit 305 includes a separate processor, a specially configured field programmable gate array (FPGA), or a specially programmed application specific integrated circuit (ASIC).

[0043] In an exemplary embodiment, the imaging device interface circuit 305 may further include hardware, software, firmware, and / or combinations thereof to instruct and control the imaging device. Various commands may be sent to the imaging device to configure the imaging device based on the received image data. For example, the imaging device interface circuit 305 may be configured to monitor and adjust exposure time, ISO sensitivity, white balance, shutter speed, gain, frame rate, dynamic range, bit depth, and other parameters related to the quality of the image data.

[0044] The image processing circuitry 306 includes hardware, software, firmware, and / or combinations thereof that support various functions associated with processing the captured image data received from the image sensor. In an exemplary embodiment, the image processing circuitry 306 may perform image processing techniques to prepare the captured image data for further processing, such as by removing optical noise, enhancing features such as edges, determining features associated with identifying objects of interest, calculating feature values ​​associated with recognizing objects represented by the captured image data, and other similar techniques known to those skilled in the art. In some embodiments, the image processing circuitry 306 may utilize image processing techniques on the processed captured image data to identify objects of interest, such as the test strip 306 and similar objects of interest. In some embodiments, the image processing circuitry 306 may utilize further image processing techniques to identify the color of the object of interest according to an associated color space, such as red-green-blue (RGB), hue-saturation-luminance (HSV), hue-lightness-saturation (HLS), luminance-blue projection-red projection (YUV, YCbCr), cyan-magenta-yellow (CMY). The determined color of the object of interest (e.g., replaceable test material 105) can be compared to the properties of the object of interest to determine the concentration of the target gas (e.g., target gas 160A and / or its oxidized derivative 160B).

[0045] Additionally or alternatively, in some embodiments, one or more of the sets of circuits 301-306 are combinable. Additionally or alternatively, in some embodiments, one or more of the sets of circuits perform some or all of the functions described in relation to another component. For example, in some embodiments, one or more of the sets of circuits 301-306 are combined into a single module embodied in hardware, software, firmware, and / or combinations thereof. Similarly, in some embodiments, one or more of the sets of circuits, e.g., imaging device interface circuit 305, are combined such that processor 301 performs one or more of the operations described above with respect to each of these circuits individually.

[0046] Additionally or alternatively, in some embodiments, one or more of the sets of circuits 301-306 are combinable. Additionally or alternatively, in some embodiments, one or more of the sets of circuits perform some or all of the functions described in relation to another component. For example, in some embodiments, one or more of the sets of circuits 301-306 are combined into a single module embodied in hardware, software, firmware, and / or combinations thereof. Similarly, in some embodiments, one or more of the sets of circuits, e.g., imaging device interface circuit 305 and / or image processing circuit 306, are combined such that processor 301 performs one or more of the operations described above with respect to each of these circuits individually.

[0047] Exemplary Methods of the Disclosure 4 and 5, exemplary methods for preparing a test material for determining the concentration of a target gas (e.g., nitric oxide) in a sample gas and for using such a test material for determining the concentration of a target gas (e.g., nitric oxide) in a sample gas are shown, respectively. That is, FIG. 4 and FIG. 5 show a flow chart including a series of steps for preparing a replaceable test material and determining the concentration of a target gas 160A (e.g., nitric oxide) in a sample gas 150, for example, using the gas detection device 100 and / or replaceable test material 105 described above.

[0048] 4, an exemplary method 400 for preparing a replaceable test material (e.g., replaceable test material 105) for determining a concentration of a target gas in a sample gas (e.g., sample gas 150) is shown. In block 402, the exemplary method 400 includes preparing a solution including a solute and a solvent, the solute including o-tolidine. In an exemplary embodiment, o-tolidine, which may also be known as 3,3'-dimethylbenzidine or 4,4'-diamino-3,3'-dimethylbiphenyl, may be in powder form and may be dissolved and / or mixed in ethanol and / or water. In an exemplary embodiment, about 5-20 mg of o-tolidine may be mixed with 1-5 mL of CH3CH2OH (>98%). In another exemplary embodiment, about 5-20 mg of o-tolidine may be mixed with 1-5 mL of CH3CH2OH (>98%) and 1-5 mL of water.

[0049] Continuing to refer to FIG. 4, at block 404, the exemplary method 400 includes introducing a test material substrate into the prepared solution for a period of time. For example, in some embodiments, a test material substrate, such as a slow test strip, may be immersed in the solution prepared at block 402 for a minimum of 30 seconds. In some further embodiments, the test material substrate may be immersed in the solution prepared at block 402 for approximately 30-120 seconds. A slow test strip may refer to a test material substrate having a tighter fiber structure with holes having smaller diameters compared to a typical test strip (e.g., a regular speed test strip). Such a slow test strip, when prepared as a replaceable test material 105, may provide a more uniform distribution of solutes (e.g., o-tolidine) once dried, allowing the sample gas 150 to pass through the strip more slowly, allowing the applied solutes to react more completely with the target gas 160A (or its oxidized derivative 160B) (if present) present in the sample gas 150.

[0050] As further shown in FIG. 4, in block 406, the exemplary method 400 includes removing at least a portion of the solvent from the test material substrate such that the test material substrate contains at least a portion of o-tolidine, thereby forming an exchangeable test material (e.g., exchangeable test material 105) for determining the concentration of the target gas (e.g., target gas 160A) in the sample gas 150. For example, removing at least a portion of the solvent from the test material substrate may include applying absorbent paper and / or wrapping the test material substrate with absorbent paper (e.g., water-absorbing paper). In some embodiments, the absorbent paper is contacted with the test material substrate for about 30-120 seconds. Additionally or alternatively, removing at least a portion of the solvent from the test material substrate may include blowing an inert gas, such as nitrogen gas, onto the test material substrate. That is, the test material substrate may be exposed to a nitrogen gas flow for a period of time, such as about 30-120 seconds. The prepared exchangeable test material 105 may be stored in a light-proof package at about -20°C to less than 4°C. Additionally or alternatively, the prepared replaceable test material 105 may be sealed in a package until use.

[0051] 5, an exemplary method for determining a concentration of a target gas (e.g., target gas 160A) in a sample gas (e.g., sample gas 150) is shown. In block 502, the exemplary method 500 includes contacting an exchangeable test material (e.g., exchangeable test material 105) with a sample gas (e.g., sample gas 150). In this case, the exchangeable test material 105 includes o-tolidine, and at least a portion of the sample gas 150 is the target gas 160A. The placement of the exchangeable test material 105 may allow the sample gas 150 containing the target gas 160A to interact with the exchangeable test material 105. For example, contacting the exchangeable test material 105 with the sample gas 150 may include exposing the exchangeable test material 105 to a flow of the sample gas 150 (e.g., sample gas flow). In a non-limiting example, the replaceable test material 105 may be placed within a gas detection apparatus, and exposing the replaceable test material 105 to the sample gas flow may include directing the sample gas flow toward the replaceable test material 105 within the gas detection apparatus.

[0052] In some embodiments, determining the concentration of the target gas 160A in the sample gas 150 may optionally include first determining the concentration of an oxidized derivative 160B of the target gas and correlating the determined concentration of the oxidized derivative 160B to the concentration of the target gas 160A. For example, if nitric oxide is the target gas 160A, the sample gas 150 may be subjected to an oxidation chamber 115 and / or exposed to an oxidizing agent 120 to transfer oxygen atoms to nitric oxide molecules, resulting in the oxidized derivative 160B, nitrogen oxide (NO2). Nitrogen dioxide may be more stable than nitric oxide and less susceptible to reaction with other chemical molecules. Thus, measuring the resulting concentration of nitrogen dioxide may provide an easier and more accurate representation of the amount of nitric oxide in the sample gas 150 than attempting to directly measure the concentration of nitric oxide.

[0053] 5, at block 504, the exemplary method 500 includes identifying a color of the exchangeable test material 105. For example, in some embodiments in which the target gas 160A is present in the sample gas 150, the exchangeable test material 105 may be configured to change color and / or shade based at least in part on the presence of the target gas 160A and / or oxidized derivatives of the target gas 160B, as described herein with respect to FIG. 4. For example, in some embodiments, the exchangeable test material 105 may change from a white or off-white color to blue, green, and / or turquoise, and / or shades of blue, green, and / or turquoise in the portion(s) of the exchangeable test material 105 contacted by the sample gas stream, such that the identified color of the exchangeable test material 105 is blue, green, and / or turquoise. For example, in a non-limiting example, o-tolidine present in or on the exchangeable test material 105 can react with nitrogen dioxide (e.g., oxidized derivative 160B of nitric oxide) present in the sample gas 150 to form nitroso-o-tolidine. In doing so, the portion(s) of the exchangeable test material 105 contacted by the sample gas stream may initially change to a yellowish orange color. If such an exchangeable test material 105 is further exposed to, for example, air, the color may then change to one or more shades of blue, green, and / or blue-green over a period of time (during which the concentration of the target gas 160A and / or the oxidized derivative 160B may be determined) due to the presence of moisture (e.g., HO) in the air. In some examples, the exchangeable test material 105 may further change to a darker color, such as brown, gray, and / or black.

[0054] In another non-limiting example where water is included as at least a portion of the solvent, o-tolidine and water present in or on the exchangeable test material 105 may react with nitrogen dioxide (e.g., oxidized derivative of nitric oxide 160B) present in the sample gas 150 to form nitro-o-tolidine. In doing so, the portion(s) of the exchangeable test material 105 contacted by the sample gas stream may initially change to one or more shades of blue, green, and / or blue-green during the period during which the concentration may be determined. In some examples, the exchangeable test material 105 may further change to a darker color, such as brown, gray, and / or black, upon exposure to air.

[0055] While the color and / or shade of the interchangeable test material 105 can be determined manually and / or visually, in some embodiments, the controller 210 can utilize various hardware and software (e.g., image processing circuitry 306) to determine the color and / or shade of the interchangeable test material 105. In some embodiments, the controller (e.g., controller 210) receives images of the interchangeable test material (e.g., interchangeable test material 105) from an imaging device (e.g., imaging device 215). In some embodiments, the captured image data can be received by the controller 210 at regular intervals, for example, based on the frame rate of the imaging device 215. In some embodiments, the image data can be received upon request of the controller 210. The image data can be transmitted in any format, for example, an image format (e.g., JPEG, PNG, GIF, BMP, TIFF, etc.) and / or a video format (e.g., MP4, AVI, MKV, MOV, WMV, etc.). Similarly, the image data may be transmitted using any transmission standard (e.g., H.264, MPEG-4, G.265, HEVC, VP8, VP9, ​​etc.). The processor 301 may receive and decode the received image data using various hardware and / or software components, such as the imaging device interface circuitry 305. In some embodiments, the controller 210 may use image processing algorithms and techniques to identify the interchangeable test material 105 and determine the color and / or shade of the interchangeable test material 105.

[0056] 5, at block 506, the exemplary method 500 includes determining a concentration of the target gas 160A in the sample gas 150 based at least in part on the identified color of the exchangeable test material 105. For example, in some embodiments, the color and / or shade of the exchangeable test material 105 identified at block 504 may vary based on the concentration of the target gas 160A and / or the oxidized derivatives 160B of the target gas such that the color and / or shade may correlate to the concentration of the target gas 160A and / or the oxidized derivatives 160B of the target gas. In some embodiments, the controller (e.g., controller 210) may determine the concentration of the target gas 160A and / or the oxidized derivatives 160B of the target gas based at least in part on the color and / or shade of the exchangeable test material 105. That is, in some embodiments, the color and / or shade of the exchangeable test material 105 may represent the concentration of the target gas 160A and / or the oxidized derivatives 160B of the target gas. For example, the interchangeable test material 105 may change to blue, green, and / or cyan in the presence of the target gas 160A and / or the oxidized derivative of the target gas 160B, with lighter shades of blue, green, and / or cyan representing concentrations less than 1%, slightly darker shades of blue, green, and / or cyan representing concentrations between 1% and 2%, etc. In another non-limiting example, red may represent concentrations less than 1%, orange may represent concentrations between 1% and 2%, yellow may represent concentrations between 2% and 4%, etc. The colors and / or shades of the correlated concentrations may be determined prior to operation and may be input into the controller 210 as configuration or operating parameters. Additionally, the colors and / or shades of the correlated concentrations may be learned, for example, through training utilizing known target gases, oxidized derivatives, and / or user input.

[0057] In some embodiments, the controller 210 may optionally consider additional parameters when determining the concentration of the target gas 160A and / or the oxidized derivatives 160B of the target gas. For example, physical properties of the test environment and / or the replaceable test material 105 may affect the determined concentration(s). The physical properties may include the temperature, humidity, and / or pressure of the test environment, the size and position of the replaceable test material 105, etc. The additional parameters may also include the gas flow rate of the sample gas 150. In some embodiments, the molecular makeup of the target gas 160A, the oxidized derivatives 160B of the target gas, and / or the sample gas 150 may be considered when determining the concentration of the target gas 160A and / or the oxidized derivatives 160B of the target gas in the sample gas 150.

[0058] Thus, specific embodiments of the present subject matter have been described. Although the specification contains many specific implementation details, these should not be construed as limiting the scope of any invention or what may be claimed, but rather as descriptions of features specific to specific embodiments of the disclosure. Other embodiments are within the scope of the following claims. Certain features described in the specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, even if features are described above as acting in a particular combination and initially claimed as such, one or more features from the claimed combination may, in some cases, be deleted from the combination, and the claimed combination may be subject to a subcombination or a variation of the subcombination.

[0059] Similarly, although acts or steps are depicted in a particular order in the figures, this should not be understood as requiring that such acts or steps may be performed in the particular order shown, or sequentially, or that all acts or steps shown be performed, to achieve a desired result, unless otherwise indicated. In certain circumstances, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and systems described may generally be integrated into a single software product or packaged into multiple software products. Any operational steps shown in dashed lines in one or more flow diagrams depicted herein are optional for purposes of the depicted embodiments.

[0060] In some cases, the actions recited in the claims may be performed in a different order and still achieve desirable results. Additionally, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results, unless specifically noted. In certain implementations, multitasking and parallel processing may be advantageous.

[0061] Terminology Overview The following explanations of terms are provided to more fully describe the present disclosure and to guide those skilled in the art in the practice of the present disclosure.

[0062] As used herein, the term "comprising" means including, but not limited to, and should be interpreted in the manner typically used in patent context. The use of broader terms such as "comprises," "includes," and "having" should be understood to provide support for narrower terms such as "consisting of," "consisting essentially of," and "comprised substantially of."

[0063] As used herein, phrases such as "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that a particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, and thus, these phrases do not necessarily refer to the same embodiment.

[0064] As used herein, the words "exemplary," "example," "exemplary," and the like are used to mean "serving as an example, instance, or illustration" without any indication of level of quality. Any implementation described herein as "exemplary" or "example" should not necessarily be construed as preferred or advantageous over other implementations.

[0065] The terms "about," "approximately," "generally," "substantially," and the like, when used in connection with a number, can mean either that particular number or a range near that particular number, as would be understood by one of ordinary skill in the art, and unless otherwise indicated, can be used to refer to within manufacturing and / or engineering design tolerances of the corresponding materials and / or elements, as would be understood by one of ordinary skill in the art.

[0066] When the specification states that a certain component or feature "may include," "can include," "could include," "should include," "would include," "preferably include," "possibly include," "typically include," "optionally include," "for example include," "often include," or "might include" (or other such phrases), or has a certain characteristic, that particular component or feature is not required to be included or to have that characteristic. Such components or features may be optionally included or excluded in some embodiments.

[0067] Where the specification presents a list, unless otherwise stated, it is to be understood that each individual member of that list, and every combination of members of that list, is a separate embodiment. For example, "1, 2, 3, 4, and 5" includes 1; 2; 3; 1 and 2; 3 and 5; 1, 3, and 5; and 1, 2, 4, and 5, among other embodiments.

[0068] The term "plurality" refers to two or more items.

[0069] The term "set" refers to a collection of one or more items.

[0070] The term "or" is used herein in both its alternative and conjunctive sense, unless otherwise indicated.

[0071] Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described herein. Unless otherwise indicated, the materials, methods, and examples are merely illustrative and not intended to be limiting. Other features of the present disclosure will be apparent from the detailed description and claims.

[0072] conclusion Many variations and other embodiments of the disclosure described herein will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. It is therefore to be understood that the disclosure is not limited to the particular embodiments disclosed, and that variations and other embodiments are intended to be included within the scope of the appended claims. Moreover, while the foregoing description and the associated drawings describe example embodiments in the context of certain example combinations of elements and / or features, it is to be understood that different combinations of elements and / or features may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, combinations of elements and / or features different from those set forth above are also contemplated as may be set forth in the appended claims. Although specific terms have been employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0073] While the present disclosure has been specifically described in conjunction with specific examples, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, the appended claims are intended to encompass any such alternatives, modifications, and variations. That is, while various embodiments according to the principles disclosed herein have been shown and described above, variations thereof may be made by those skilled in the art without departing from the spirit and teachings of the present disclosure. The embodiments described herein are merely representative and are not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of the present disclosure. Although the disclosed embodiments are primarily directed to the detection of nitric oxide and / or its oxidized derivative, nitrogen dioxide, in the sample gas 150, those skilled in the art will recognize that such principles may be applied to any target gas 160A in any environment. For example, other gases and / or volatile organic compounds (VOCs) may also be detected using these techniques. Some exemplary gases may include, but are not limited to, hydrogen sulfide (H2S), ammonia (NH3), carbon monoxide (CO), formaldehyde (HCHO), benzene (C6H6), and other similar gases. Alternative embodiments resulting from combining, integrating, and / or omitting features of the embodiment(s) are also within the scope of the present disclosure. Thus, the scope of protection is not limited by the description set forth above.

[0074] In addition, the section headings used herein are provided to conform to the suggestions of 37 C.FR 1.77 or to otherwise provide organizational guidance, and are not intended to limit or characterize the invention(s) recited in any claim that may be issued from this disclosure.

Claims

1. 1. A method for preparing a replaceable test material for determining a concentration of a target gas in a sample gas, comprising: preparing a solution comprising a solute and a solvent, the solute comprising o-tolidine; introducing a test material substrate into said prepared solution for a period of time; removing at least a portion of the solvent from the test material matrix such that the test material matrix contains at least a portion of the o-tolidine, thereby forming the exchangeable test material for determining a concentration of a target gas in the sample gas; A method comprising:

2. 1. A method for determining a concentration of a target gas in a sample gas, comprising: contacting an exchangeable test material with the sample gas, where at least a portion of the sample gas is the target gas, and where the exchangeable test material comprises o-tolidine; identifying a color of the interchangeable test material; determining the concentration of the target gas in the sample gas based at least in part on the identified color of the replaceable test material; A method comprising:

3. 1. A reusable gas detection device for determining a concentration of a target gas in a sample gas, comprising: a replaceable test material configured to change color based at least in part on the presence of a target gas in the sample gas or an oxidized derivative of the target gas in the sample gas, the replaceable test material comprising o-tolidine; and a controller configured to determine the concentration of the target gas; A reusable gas detection device comprising:

Images