阅读说明：本技术 通过感测昆虫幼虫和昆虫成虫的挥发性信息素和化学信息素来检测储藏物中的昆虫幼虫和昆虫成虫的装置 (Device for detecting insect larvae and adult insects in a store by sensing volatile and chemical pheromones of insect larvae and adult insects ) 是由 尼古拉斯·约瑟夫·斯米兰尼奇 赛缪尔·费尔斯通·赖克特 法兰克·伯纳德·图德龙 于 2019-02-01 设计创作，主要内容包括：用于通过感测诸如挥发性信息素、化学信息素和利它素之类的气相标志物来检测储藏物中存在的昆虫幼虫和昆虫成虫的低成本、高精确度且便携的装置。本文公开的方法、装置和系统利用了传感器阵列,传感器阵列配置为同时测量多个目标标志物并过滤背景气体,同时保持紧凑、高度精确且易于操作。(A low cost, high precision and portable device for detecting insect larvae and adult insects present in a deposit by sensing gas phase markers such as volatile pheromones, semiochemicals and kairomones. The methods, devices, and systems disclosed herein utilize a sensor array configured to simultaneously measure multiple target markers and filter background gas while remaining compact, highly accurate, and easy to operate.)

1. A method of identifying insect infestation of a deposit by detecting one or more target Volatile Organic Compounds (VOCs) within a target fluid stream, the method comprising:

providing an apparatus, the apparatus comprising:

a sensor array comprising a plurality of VOC sensors, wherein each VOC sensor comprises:

a substrate having a first side and a second side;

a resistive heater circuit formed on the first side of the substrate;

a sensing circuit formed on the second side of the substrate; and

a chemically sensitive film formed over the sensing circuitry on the second side of the substrate;

heating one or more of the plurality of VOC sensors to at least a first operating temperature;

contacting the one or more VOC sensors with the target fluid stream;

determining a set of conductance change values (Δ K) corresponding to each of the one or more VOC sensors in contact with the target fluid stream_i) (ii) a And

determining a concentration of a gas component ([ X ] of one or more target VOCs) within the target fluid stream based on the set of conductance change values]_n)。

2. The method of claim 1, wherein the method further comprises:

measuring a signal conductance of the one or more VOC sensors after contacting the one or more VOC sensors with the target fluid stream;

wherein the set of conductance change values (Δ K) is determined based on a difference between the signal conductance of each of the one or more VOC sensors in contact with the target fluid stream and a baseline conductance of each of the respective VOC sensors_i)。

3. The method of claim 2, wherein the baseline conductance of the one or more VOC sensors is measured when the one or more VOC sensors are in an atmosphere free of any target VOC.

4. The method of claim 3, wherein the method further comprises:

adjusting the baseline conductance of one or more VOC sensors after contact with at least one target VOC to match the baseline conductance of the respective VOC sensor prior to contact with at least one target VOC, wherein the baseline conductance is adjusted by heating one or more VOC sensors to at least a second operating temperature.

5. The method of claim 2, wherein the method further comprises:

contacting one or more of the plurality of VOC sensors with a sample fluid stream, the sample fluid stream being free of any target VOC; and

measuring the baseline conductance of the one or more VOC sensors.

6. The method of claim 1, wherein the method further comprises:

determining one or more specific net conductance values for one or more VOC sensors, wherein each specific net conductance value corresponds to one of the target VOCs.

7. The method of claim 6, wherein the specific net conductance value for each corresponding target VOC is determined by:

contacting the one or more VOC sensors with a control fluid stream having a known concentration of the target VOC;

measuring a test conductance of each of the one or more VOC sensors; and

for each of the one or more VOC sensors, a specific net conductance value is calculated based on the measured test conductance of the VOC sensor and the known concentration of the target VOC within the control fluid stream.

8. The method of claim 7, wherein the method further comprises:

determining a plurality of specific net conductance values for one or more VOC sensors, wherein each of said specific net conductance values for each of said VOC sensors corresponds to a different target VOC.

9. The method of claim 6, wherein the gas constituent concentration ([ X ] of the one or more target VOCs within the target fluid stream is determined based on the set of conductance changes and one or more specific net conductance values for each of the one or more VOC sensors]_n)。

10. The method of claim 1, wherein the first operating temperature is between about 180 ℃ and about 400 ℃.

11. The method of claim 1, wherein the target fluid flow is an air sample taken from within a vicinity of the reservoir to be evaluated.

12. A device for detecting one or more target Volatile Organic Compounds (VOCs) within a target fluid stream, the device comprising:

a sensor array having a plurality of VOC sensors, wherein each VOC sensor comprises:

a substrate;

a resistive heater circuit formed on a first side of the substrate;

a sensing circuit formed on a second side of the substrate; and

a chemically sensitive film formed over the sensing circuitry on the second side of the substrate.

13. The device of claim 12, wherein the sensor array comprises about two to about ten VOC sensors.

14. The device of claim 12, wherein the resistive heater circuit of at least one of the plurality of VOC sensors is a serpentine pattern having a warp wire width of about 0.288mm to about 0.352mm and a warp wire spacing width of about 0.333mm to about 0.407 mm.

15. The device of claim 12, wherein the sensing circuitry of at least one of the plurality of VOC sensors comprises first and second sensing elements forming a pair of extended interdigitated contacts;

wherein the first sensing element comprises a plurality of extended contacts, each contact having a latitudinal wire width of about 0.162mm to about 0.198mm and a latitudinal wire spacing of about 0.738mm to about 0.902 mm; and

wherein the second sensing element comprises a plurality of extended contacts, each contact having a latitudinal wire width of about 0.162mm to about 0.198mm and a latitudinal wire spacing of about 0.738mm to about 0.902 mm.

16. The device of claim 15, wherein each of the first and second sensing elements comprises at least three extended contacts, and wherein the sensing circuitry has a latitudinal wire spacing between each extended contact of the first and second sensing elements of about 0.288mm to about 0.352 mm.

17. The device of claim 12, wherein at least one of the resistive heater circuit and the sensing circuit is formed from a composition comprising platinum, and the chemically sensitive film is a nanocrystalline tin oxide film formed from an aqueous tin oxide gel.

18. The device of claim 12, wherein the chemically sensitive membrane comprises a dopant selected from the group consisting of: platinum; palladium; molybdenum; tungsten; nickel; ruthenium; and osmium.

19. The apparatus of claim 12, wherein the sensor array is operatively connected to a controller configured to:

measuring a conductance of one or more VOC sensors of the plurality of VOC sensors;

determining a set of conductance change values corresponding to each of the one or more VOC sensors in contact with the target fluid stream; and

determining a gas constituent concentration of one or more target VOCs within the target fluid stream based on the set of conductance change values.

20. A system for identifying insect infestation of a deposit, the system comprising:

a test chamber enclosing a sensor array, the sensor array comprising a plurality of VOC sensors;

an air transfer unit configured to recover a fluid flow and deliver the fluid flow to the testing chamber; and

a controller operatively connected to the air delivery unit and the sensor array, wherein the controller is configured to:

operating the air transfer unit to recover the fluid stream from the testing chamber and deliver the fluid stream to the testing chamber, wherein one or more of the plurality of VOC sensors are in fluid contact with the fluid stream;

operating the sensor array to measure conductance of one or more VOC sensors of the plurality of VOC sensors;

determining a set of conductance change values corresponding to each of the one or more VOC sensors; and

determining a gas constituent concentration of one or more target VOCs within the fluid stream based on the set of conductance change values.

21. The system of claim 19, wherein at least one of the one or more target VOCs within the fluid stream is selected from the group consisting of: 4, 8-dimethyldecanal; (Z, Z) -3,6- (11R) -dodecadien-11-olide; (Z, Z) -3, 6-dodecadienolide; (Z, Z) -5,8- (11R) -tetradecadien-13-olide; (Z) -5-tetradecene-13-lactone; (R) - (Z) -14-methyl-8-hexadecenal; (R) - (E) -14-methyl-8-hexadecenal; gamma-ethyl-gamma-butyrolactone; (Z, E) -9, 12-tetradecadienylacetate; (Z, E) -9, 12-tetradecadien-1-ol; (Z, E) -9, 12-tetradecadienal; (Z) -9-tetradecene acetate; (Z) -11-hexadecene acetate; (2S,3R, 1' S) -2, 3-dihydro-3, 5-dimethyl-2-ethyl-6 (1-methyl-2-oxobutyl) -4H-pyran-4-one; (2S,3R, 1' R) -2, 3-dihydro-3, 5-dimethyl-2-ethyl-6 (1-methyl-2-oxobutyl) -4H-pyran-4-one; (4S,6S,7S) -7-hydroxy-4, 6-dimethyl-3-nonanone; (2S,3S) -2, 6-diethyl-3, 5-dimethyl-3, 4-dihydro-2H-pyran; 2-palmitoyl-1, 3-cyclohexanedione; and 2-oleoyl-1, 3-cyclohexanedione.

Background

The following disclosure relates generally to insect and insect infestation detection techniques, chemical sensing techniques, gas detection techniques, volatile organic compound analysis techniques, gas sensing microchip arrays, and methods and apparatus related thereto. The present invention finds particular application in connection with techniques involving highly sensitive and selective detection of insects in stored food and other products or materials.

Storage insects ("SPI") are most commonly found in food products, food materials, or infesting equipment that prepares, processes, packages, or stores the food. The economic losses these pests cause in processing, transportation and storage systems can be millions of dollars per pollution, product recall, consumer complaints/prosecution, and pest control application events (Arthur et al, 2009). In addition, some SPI can have health consequences if taken inadvertently, causing gastric stress in infants and the elderly (Okamura, 1967).

Current insect detection relies on flashlight inspection and the use of traps with a variety of synthetic pheromone lures and traps that capture SPI adults. Pheromones are volatile organic compounds ("VOCs") emitted from males and/or females of an individual species. Pheromone lures and traps are dependent on insect mobility, and these can be significantly affected by temperature. Pheromone volatility, quantity/mass, and human mobility and insect dynamics interact with these elements, resulting in considerable variability in trap data. The interpretation of trap capture is based on a small sampling of the population (2% to 10% or less). This makes detection and remediation of pest infestation difficult.

Indian meal moth ("IMM") is the most common deposit insect found in the United states (Mueller, 1998; Resener 1996). In the united states, such insects are more common than any other insect in the storage of food and grain. IMM adults can be found almost anywhere in the temperate regions of the world. Furthermore, in the united states and europe, IMM is one of the pests responsible for the greatest damage. This insect survives so well in our environment for two reasons: 1) during the transient life of the female, it lays down a large number of eggs; and 2) genetic alteration of IMM or the ability to survive in humans in response to pesticides used to protect their food (drug resistance). IMM was found to be the most resistant insect known to man. During the fifty years, the genetic composition of this insect has been altered to combat the commonly used insecticide Malathion (Malathion). In the 70's of the 19 th century, IMM began to show evidence of resistance to this common pesticide. IMM gave 60,000 times the resistance to this insecticide.

IMM is most commonly found on equipment that prepares, processes, packages or stores food as finished food, food materials such as stored wheat products, milled/processed wheat and other stores such as milled cereal products, flour, bran, pasta products, spices, or infests. IMM larvae are the destructive life stage of the insect and are very greedy. Larvae are highly mobile and can constantly seek new food sources. The value of foods is destroyed by the food they consume, the woodchips they leave, and the net that larvae leave as they move.

In addition, IMM is often a precursor to insects for other stores. Infection with untreated IMM may be an indicator of impending infection with other SPIs (Mueller, 2016). The five most common storage insects (SPIs) include Indian meal moth (Indian meal moth Plodia interpunctella), warehouse beetles (bark beetle varibian), mealworm beetles (Tribolium spp.), corn beetles (Oryzaphium spp.), and tobacco beetles (Nicotiana tabacum sericorn) (Mueller, 1998; Hagstrum and Subramanyam, 2006). The economic losses caused by these pests in processing, transportation and storage can be millions of dollars per pollution, product recall, consumer complaints/prosecution, and pest control application events (Arthur, 2009). However, there is no effective low cost method to monitor and detect them.

Several SPI pheromones have been identified but are not commercially available due to short shelf life and production cost (Phillips et al, 2000). These compounds are unique, but can attract interspecific competitors, such as in storage food moth populations and complex species of the genus pissodes. The single pheromone (Z, E) -9, 12-tetradecadienylacetate is the major pheromone of the genus oryza incertulas, but will attract the other three food moths of the species mealworm. The pheromone compound R, Z14-methyl-8-hexadecenal is a major component that attracts storage beetles (bark beetles), but will also attract three other common species of the genus bark beetle, including quarantine pests (bark beetles, khapra beetles). A single compound, 4, 8-dimethyldecanal, attracts several tenebrio molitor (species of the genus theliopsis), and (Z, Z) -3, 6-dodecadien-11-olide attracts two species of tenebrio molitor (species of the genus diabrotica), but the pheromone (4S,6S,7S) -4, 6-dimethyl-7-hydroxy-3-nonanone of the tobacco beetle (tobacco beetle) is unique to this species.

Furthermore, with respect to possible target semiochemicals and/or kairomones, these semiochemicals and kairomones are high molecular weight VOCs. As a result, their vapor pressure and concentration in the headspace above infested stores will be low and therefore more difficult to detect.

Accordingly, it is desirable to eliminate variability and uncertainty in detecting pest presence/absence, abundance, and location through the use of methods, devices, and systems that can detect and determine the concentration of multiple pheromones. Furthermore, it would be desirable to provide methods, devices and systems that can detect other deposit insect larvae by sensing semiochemicals/kairomones of the insect larvae in a similar manner. The threshold concentration may be established to immediately determine whether the most common SPI is present in a trailer, land/sea container, bulk tote, pallet or closet of bagged material. It is also desirable to provide the ability to detect VOC concentration gradients, which help to locate and accurately describe structures, wall voids, cracks and crevices or SPI infestation within a device. Furthermore, it would be desirable to provide a handheld device that can eliminate many of the dependencies on insect mobility and environment as factors affecting activity from the SPI monitoring model.

Cited references

The following references are mentioned, the entire disclosures of which are incorporated herein by reference:

Arthur F.H.Johnson J.A.Neven L.G.Hallman G.J.Follett P.A.(2009).Insect Pest Management in Postharvest Ecosystems in the United States ofAmerica.Outlooks on Pest Management,20:279–284.

hagstrum D.W. and Subramanyam B. (2006). Fundamentals of Stored-produced engineering.St.Paul: AACC Int.

Mueller, David K (1998). Stored Product Protection A Period of Transmission. instruments Limited, Ind. Pernals.

Okumura, G.T, (1967). A Report of Cantharis and Allergy used by Trogopera (Coleoptera: Dermestidae). California Vector Views, Vol.14No.3, pages 19-22.

Phillips, T.W., Cogan, P.M., and Fadamiro, H.Y. (2000). Pheromones in B.Subramanyam and D.W.Hagstrum (Eds.). Alternatives to Pesticides in Stored-Product IPM, p.273. 302. Boston Kluwer academic Press, Mass

Resener, A.M (1997). National Survey of Stored produced instruments. Fumigants and Pheromones, pp.46, 3-4.

Disclosure of Invention

Disclosed in various embodiments herein are low-cost and high-precision methods, devices, and systems for identifying insect infestation of a storage (e.g., food) based on the detection of one or more target volatile organic compounds ("VOCs") within a target fluid stream (e.g., an air sample) sampled from the vicinity of the storage. The disclosed methods, systems and devices with minimal cost and high precision enable real-time, non-invasive detection of insect larva semiochemicals/kairomones or insect adult pheromones in the environment of a deposit.

According to a first embodiment of the present disclosure, there is provided a method of identifying insect infestation of a deposit by detecting one or more target VOCs within a target fluid stream, the method comprising the steps of: providing a device comprising a sensor array having a plurality of VOC sensors; heating one or more VOC sensors of a plurality of VOC sensors to at least a first operating temperature; contacting one or more VOC sensors with a target fluid stream; determining a set of conductance change values corresponding to each of the one or more VOC sensors in contact with the target fluid stream; and determining a gas constituent concentration of one or more target VOCs within the target fluid stream based on the set of conductance change values. Further, each VOC sensor of the provided sensor array comprises: a substrate having a first side and a second side; a resistive heater circuit formed on a first side of a substrate; a sensing circuit formed on a second side of the substrate; and a chemically sensitive film formed over the sensing circuitry on the second side of the substrate. In particular embodiments, the method may include correcting the baseline resistance of the VOC sensor to an earlier baseline value after sampling the VOC marker in the fluid stream, which may be accomplished by adjusting the operating temperature of one or more VOC sensors after each sampling of the target VOC.

In accordance with another embodiment of the present disclosure, there is provided an apparatus for detecting one or more target VOCs within a target fluid stream, the apparatus comprising: a sensor array having a plurality of VOC sensors, wherein each VOC sensor comprises: a substrate; a resistive heater circuit formed on a first side of a substrate; a sensing circuit formed on a second side of the substrate; and a chemically sensitive film formed over the sensing circuitry on the second side of the substrate.

In accordance with another embodiment of the present disclosure, there is provided a system for identifying insect infestation of a deposit, the system comprising: a test chamber surrounding the sensor array; an air transfer unit configured to recover a fluid flow and deliver the fluid flow to a testing chamber; and a controller operatively connected to the air delivery unit and the sensor array. The sensor array includes a plurality of VOC sensors, and the controller is configured to: operating the air transfer unit to withdraw the fluid stream from the target area and deliver the fluid stream to the testing chamber; operating the sensor array to measure the conductance of one or more of the plurality of VOC sensors; determining a set of conductance change values corresponding to each of the one or more VOC sensors; and determining a concentration of the gas component of the one or more target VOCs within the fluid stream based on the set of conductance change values.

Drawings

The disclosure may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for the purpose of illustrating preferred embodiments and are not to be construed as limiting the disclosure.

Fig. 1 is a flow diagram illustrating a method of identifying insect infestation according to one embodiment of the present application.

Fig. 2A-2B are flow diagrams illustrating another method of identifying insect infestation according to another embodiment of the present application.

Fig. 3 is a block diagram illustrating a system configured to perform the methods disclosed herein, according to one embodiment of the present application.

Fig. 4A-4B are schematic views of a first side (fig. 4A) and a second side (fig. 4B) of a single VOC sensor according to certain embodiments of the present application.

Fig. 5 is a schematic view of a single VOC sensor suspended in a holder according to one embodiment of the present application.

Fig. 6 is a representative side cross-section of a sensor array including a plurality of VOC sensors according to an embodiment of the present application.

FIG. 7 is a block diagram of an infestation detection system according to one embodiment of the present application.

Fig. 8A to 8D are graphs showing the sensitivity of a VOC sensor array according to an embodiment of the present application to various target volatile organic compounds.

Fig. 9A-9C are graphs showing the response of a first VOC sensor to the presence of three target deposit insects ("SPIs"), according to one embodiment of the present application.

Fig. 10A-10C are graphs showing the response of a second VOC sensor to the presence of three target deposit insects ("SPIs"), according to another embodiment of the present application.

Fig. 11A-11C are graphs showing the response of a third VOC sensor to the presence of three target deposit insects ("SPIs"), according to one embodiment of the present application.

Fig. 12A-12C are graphs showing the response of a fourth VOC sensor according to one embodiment of the present application to the presence of three target deposit insects ("SPIs").

Fig. 13A-13D are graphs showing the response of four VOC sensors to the presence of varying amounts of three target deposit insects ("SPIs"), according to one embodiment of the present application.

Detailed Description

In the following specification and the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings.

Definition of

In the following specification and the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings. Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings, and are not intended to define or limit the scope of the disclosure. In the drawings and the following description, it is to be understood that like numeric designations refer to components having like functions. Further, it should be understood that the drawings are not to scale.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

In this document, the term "comprising" is used as requiring the presence of specified components/steps and allowing the presence of other components/steps. The term "comprising" should be interpreted as including the term "consisting of … …" allowing only the specified components/steps to be present.

Numerical values should be understood to include the following: the numerical values are the same when reduced to the same number of significant digits and the numerical values differ from the stated value by less than the experimental error of conventional measurement techniques of the type described in this application to determine the value.

All ranges disclosed herein are inclusive of the endpoints and independently combinable (e.g., a range of "2 mm to 10 mm" is inclusive of the endpoints, 2mm and 10mm, and all intermediate values).

The term "about" may be used to include any numerical value that may be varied without changing the basic function of the value. When used with a range, "about" also discloses the range defined by the absolute values of the two endpoints, e.g., "about 2 to about 4" also discloses the range "2 to 4". More specifically, the term "about" can refer to plus or minus 10% of the indicated number.

The terms "ppm" and "ppb" should be understood to mean "parts per million" and "parts per billion", respectively. As used herein, "ppm", "ppb", and the like refer to volume fraction, not mass fraction or mole fraction. For example, a value of 1ppm may be expressed as 1 μ V/V, while a value of 1ppb may be expressed as 1 nV/V.

The present disclosure may be understood more readily by reference to the following detailed description and the various drawings discussed therein.

Method of producing a composite material

Disclosed herein are methods for determining the presence of insect infestation in stores by highly sensitive and highly selective detection of the presence of one or more target volatile organic compounds ("VOCs"), such as certain semiochemicals, kairomones and/or pheromones of various store insects ("SPIs").

Referring to fig. 1, a method 100 of identifying insect infestation of a deposit by detecting one or more target volatile organic compounds within a target fluid stream is provided. The method comprises the following steps: providing a device comprising a sensor array having a plurality of VOC sensors (S110); heating one or more VOC sensors of the plurality of VOC sensors to at least a first operating temperature (S115); contacting one or more VOC sensors with a target fluid stream (S120); determining a set of conductance change values corresponding to each of the one or more VOC sensors in contact with the target fluid stream (S125); and determining a gas constituent concentration of the one or more target VOCs within the target fluid stream based on the set of conductance change values (S130). According to a first embodiment of the method 100, each VOC sensor of the sensor array comprises: a substrate; a resistive heater circuit; a sensing circuit; and a chemically sensitive film formed over the sensing circuit. In some implementations, a resistive heater circuit can be formed on a first side of a substrate, a sensing circuit can be formed on a second side of the substrate, and a chemically sensitive film can be formed over the sensing circuit on the second side of the substrate.

In particular embodiments, the method 100 includes measuring the signal conductance of the one or more VOC sensors after contacting the one or more VOC sensors with the target fluid stream. That is, a set of conductance change values may be determined based on a difference between the signal conductance of each of the one or more VOC sensors in contact with the target fluid stream and the baseline conductance of each of the respective VOC sensors. In some embodiments, the baseline conductance of the one or more VOC sensors is determined when the one or more VOC sensors are in an atmosphere that does not contain any target VOCs.

In a preferred embodiment, the target fluid stream is an air sample taken from the vicinity of the reservoir being evaluated for possible insect infestation. That is, the target fluid flow may be a gas sample from a headspace above the target reservoir.

Method 100 begins at S105 and ends at S135, however, in particular embodiments, method 100 may be repeated (e.g., repeating steps S110-S130) by sampling multiple streams of a target fluid (e.g., air samples) from multiple adjacent areas of a deposit to be evaluated. That is, the method 100 may identify a gradient of potential insect infestation by sampling one or more target fluid streams at multiple distances from the storage (e.g., at distances less than about 1 foot from the storage; at distances between about 1 foot and 2 feet from the storage; at distances between about 2 feet and 3 feet from the storage; etc.).

In further embodiments, the one or more target VOCs are semiochemicals, kairomones and/or pheromones associated with one or more insects such as SPI. In particular, the one or more target VOCs can be semiochemicals, kairomones and/or pheromones associated with, for example, tribolium castaneum, warehouse beetles, indian meal moth and/or tobacco beetles. In particular embodiments, at least one of the one or more target VOCs within the fluid stream may be selected from the group consisting of: 4, 8-dimethyldecanal; (Z, Z) -3,6- (11R) -dodecadien-11-olide; (Z, Z) -3, 6-dodecadien-lactone; (Z, Z) -5,8- (11R) -tetradecadien-13-olide; (Z) -5-tetradecene-13-lactone; (R) - (Z) -14-methyl-8-hexadecenal; (R) - (E) -14-methyl-8-hexadecenal; gamma-ethyl-gamma-butyrolactone; (Z, E) -9, 12-tetradecadienylacetate; (Z, E) -9, 12-tetradecadien-1-ol; (Z, E) -9, 12-tetradecadienal; (Z) -9-tetradecene acetate; (Z) -11-hexadecene acetate (Hexa-decenyl acetate); (2S,3R, 1' S) -2, 3-dihydro-3, 5-dimethyl-2-ethyl-6 (1-methyl-2-oxobutyl) -4H-pyran-4-one; (2S,3R, 1' R) -2, 3-dihydro-3, 5-dimethyl-2-ethyl-6 (1-methyl-2-oxobutyl) -4H-pyran-4-one; (4S,6S,7S) -7-hydroxy-4, 6-dimethyl-3-nonanone; (2S,3S) -2, 6-diethyl-3, 5-dimethyl-3, 4-dihydro-2H-pyran; 2-palmitoyl-1, 3-cyclohexanedione; and 2-oleoyl-1, 3-cyclohexanedione.

Referring to fig. 2A and 2B, a method 200 of identifying insect infestation of a deposit by detecting one or more target volatile organic compounds within a target fluid stream is provided according to another embodiment of the present disclosure. The method 200 begins at S202.

In step S04, a device is provided that includes a sensor array having a plurality of VOC sensors. Each VOC sensor of the sensor array comprises: a substrate; a resistive heater circuit; a sensing circuit; and a chemically sensitive film formed over the sensing circuit. In some implementations, a resistive heater circuit can be formed on a first side of a substrate, a sensing circuit can be formed on a second side of the substrate, and a chemically sensitive film can be formed over the sensing circuit on the second side of the substrate.

In particular embodiments, the sensor array comprises a plurality of different VOC sensors. That is, by including a catalytic material in the chemically sensitive film (i.e., active layer), the surface composition of one or more of the plurality of VOC sensors can be altered. In other words, the chemically sensitive film of the one or more VOC sensors may comprise a dopant. In some embodiments, the dopant can be, for example, a transition metal. For example, the dopant may be selected from the group consisting of: platinum; palladium; molybdenum; tungsten; nickel; ruthenium; osmium.

In step S206, one or more VOC sensors of the plurality of VOC sensors are heated to at least a first operating temperature. In particular embodiments, the working temperature is between about 180 ℃ and about 400 ℃. In other embodiments, the operating temperature of one or more VOC sensors is maintained during subsequent steps of the method. In particular, the heating circuit of each VOC sensor can be used to measure and control the temperature of the VOC sensor throughout its operation.

In particular embodiments of the method 200, the method may include one or more calibration steps 208, the calibration steps 208 including: contacting one or more VOC sensors of the plurality of VOC sensors with a sample fluid stream, the sample fluid stream being free of any target VOC (S210); measuring a baseline conductance of the one or more VOC sensors (S212); optionally, removing the fluid stream from contact with the one or more VOC sensors (S216); contacting one or more VOC sensors with a control fluid stream having a known concentration of a target VOC (S218); measuring a control conductance of each of the one or more VOC sensors (S220); calculating a specific net conductance value based on the measured control conductance of the VOC sensor and the known concentration of the target VOC within the control fluid stream (S222); and repeating at least steps S218 to S222(S226) for a plurality of control fluid streams. The calibration step 208 may also include: removing the fluid stream from contact with the one or more VOC sensors (S228); and adjusting the baseline conductance of the one or more VOC sensors after contact with the at least one target VOC (S230).

In step S210, one or more VOC sensors of the plurality of VOC sensors are contacted with the sample fluid stream. In a preferred embodiment, the sample fluid stream is a volume of air without any target VOC that can be tested with the method 200.

In step S212, a baseline conductance of one or more VOC sensors in contact with the sample fluid stream is measured using the sensing circuitry of the VOC sensors. Since the thin film formed on the sensing circuitry of the VOC sensor is chemically sensitive (e.g., semi-conductive), the current flowing in the material is due to electrons in the conduction band of the thin film, which may be affected by undesired and/or target compounds (e.g., target VOCs). Thus, after the operating temperature is reached and contacted with a gas sample (i.e., sample fluid stream) that does not contain a marker gas (i.e., a fluid stream having at least one target VOC) in step S206, the resistance of the VOC sensor is measured and recorded as a baseline resistance or baseline conductance. In some embodiments, a set of baseline conductances is determined

And the set of baseline conductances includes a baseline conductance for each of the plurality of VOC sensors (e.g.)。

In step S216, the sample fluid stream is brought out of contact with the VOC sensors of the sensor array. In particular embodiments, this may include purging a chamber or reactor containing the sensor array and/or one or more VOC sensors.

In step S218, one or more VOC sensors are contacted with a control fluid stream (e.g., a marker gas) having a known concentration of at least one target VOC.

In step S220, a control conductance of each of the one or more VOC sensors in contact with the control fluid stream is measured. The resistance/conductance of the VOC sensor changes because contact with the control fluid stream can make more or less electrons available for chemically sensitive membrane based conduction.

Then, in step S222, a specific net conductance value for each of the one or more VOC sensors is determined based on the measured test conductance of the VOC sensor and the known concentration of the target VOC within the control fluid stream. As studied and disclosed herein, the amount of conductance change may be proportional to the concentration of the gas, where the specific net conductance ("SNC") as used herein refers to the proportionality coefficient. In particular embodiments, the first target VOC concentration of the control fluid stream is from about 10ppb to about 400 ppb. In a preferred embodiment, the control fluid stream has a target VOC concentration of about 200 ppb.

For one or more of the plurality of VOC sensors, the resulting change between the baseline conductance and the measured control conductance is determined and divided by the indicated (i.e., known) concentration to give the SNC value (i.e., a measure of the sensitivity of the chip to the gas), typically expressed in units of "nano-mho/parts per billion" or "nmho/ppb". In this application, each chip will have a different SNC for each target gas of interest.

For further calibration, in step S226, at least steps S218-S222 may be repeated for additional control fluid flows to obtain a plurality of specific net conductance ("SNC") values for one or more VOC sensors, wherein each specific net conductance value for each VOC sensor corresponds to a different target VOC. In some embodiments, the plurality of SNC values is a set of SNC values ({ SNC_i,X} 224, and the set of SCN values includes SNC values for one or more target VOCs corresponding to each of the plurality of VOC sensors (e.g., for a first VOC sensor,

in the case of the second VOC sensor,

etc.) wherein X is_nRepresents a particular target VOC.

The method 200 may also include a step including adjusting a baseline conductance/resistance of one or more VOC sensors (S230/S232). For example, after contact with one or more target VOCs, the subsequent (i.e., post-contact) baseline conductance of the VOC sensor may be different from the baseline conductance of the VOC sensor prior to contact with the target VOCs. In particular embodiments, such baseline conductance changes may be accounted for by adjusting the baseline conductance after contact with one or more target VOCs in steps S230/S232. During the calibration process 208, the control fluid flow may be removed (e.g., from the sensor array chamber) in step S228, and then the conductance of the VOC sensor may be adjusted in step S230 by: the conductance of each VOC sensor is measured to determine the post-contact conductance of the VOC sensor, the post-contact conductance is compared 214 to the baseline conductance, and the one or more VOC sensors are heated to at least a second operating temperature such that the conductance of each VOC sensor at the second operating temperature matches the corresponding pre-contact baseline conductance 214. Based on the measured post-contact conductance of the VOC sensors, the second operating temperature of each VOC sensor may be higher or lower than the first operating temperature of the respective VOC sensor.

Turning to fig. 2B, after the calibration step 208, the baseline conductance of the VOC sensor may be adjusted in step S232 by: the method includes the steps of cleaning a sensor array chamber of the target VOC, measuring the conductance of one or more VOC sensors, comparing the measured conductance to a corresponding baseline conductance, and heating the one or more VOC sensors to at least a second operating temperature such that the conductance of each VOC sensor at the second operating temperature matches the corresponding baseline conductance 214.

After the adjusting step S232 or the heating step S206, the one or more VOC sensors are contacted with the target fluid stream at step S234. In particular embodiments, the target fluid stream is an air sample taken from the vicinity of the reservoir being evaluated for possible insect infestation. Thus, the target fluid stream may comprise one or more target VOCs, such as semiochemicals, kairomones and/or pheromones associated with one or more insects (e.g., SPI). For example, for certain SPIs, several pheromones and semiochemicals are listed in tables 1 and 2 below:

TABLE 1 SPI and pheromones thereof

TABLE 2 IMM pheromone and semiochemical components

In step S236, the signal conductance of the one or more VOC sensors is measured after contacting the one or more VOC sensors with the target fluid stream.

Then, in step S238, a set of conductance change values ({ Δ K) for one or more VOC sensors of the sensor array is determined_i}). In particular embodiments, for each VOC sensor, the conductance change value may be determined as follows:

wherein i is an integer,. DELTA.K_iIs the conductance change value, K, of the VOC sensor i_iFor measuring the signal conductance of the VOC sensor i in the presence of a target fluid flow

Is the baseline conductance of the VOC sensor i.

In step S240, a gas constituent concentration ([ X ] of one or more target VOCs within the target fluid stream is determined based on the set of conductance change values]_n). In particular embodiments, more than one target may be present in the target fluid stream, in addition to other background and/or interfering gasesVOC, making analysis difficult. In particular embodiments, the concentration of the gas constituent of the one or more target VOCs ([ X ") within the target fluid stream is determined based on the set of conductance change values and the one or more SNCs for each VOC sensor]_n). In other embodiments, the concentration of the gas constituent of one or more target VOCs ([ X ]) within the target fluid stream is determined by solving a system of equations]_n) For example, the system of equations shown below:

ΔK₁＝SNC_1A[A]+SNC_1B[B]+SNC_1C[C]+SNC_1D[D]

ΔK₂＝SNC_2A[A]+SNC_2B[B]+SNC_2C[C]+SNC_2D[D]

ΔK₃＝SNC_3A[A]+SNC_3B[B]+SNC_3C[C]+SNC_3D[D]

ΔK₄＝SNC_3A[A]+SNC_4B[B]+SNC_4C[C]+SNC_4D[D]

wherein Δ K_iFor a measured change in conductance of sensor "i", i "is in the range of 1 to 4, SNC_ijFor "specific net conductance" of sensor "i" when contacted by gas (e.g., target VOC) "j", which is gas or gas species A, B, C or D, and [ X]Is the concentration of gas A, B, C or D, expressed as gas volume-to-volume, i.e., liters of gas per liter of total atmosphere.

Although only four target VOCs (i.e., A, B, C and D) and four sensors (i.e., 1, 2,3, and 4) are shown above, the number of target VOCs and the number of VOC sensors present in the analysis may vary depending on different applications or different uses and is not limited to only four. As a result, the problem of determining the concentration of several target VOCs and/or background gases and interfering gases present within a certain fluid stream becomes possible.

In some embodiments, the method 200 may further include operating a user interface to communicate the results of the analysis (S242). That is, the apparatus provided in step S204 may further include a user interface configured to display the results of the analysis of the target fluid flow to an associated user. For example, the user interface can be configured to display or otherwise indicate the presence of an insect infestation, including the presence of one or more insects (e.g., SPI). The presence of an infestation is indicated based on a predetermined threshold concentration, which may be associated with the type of storage facility (e.g., within a trailer, land/sea container, bulk tote, pallet or storage room of bagged material) or the type of storage being tested. The user interface may be further configured to display or otherwise indicate the level of insect presence (e.g., the extent of infestation) based on the detected target VOC.

In particular embodiments, the user interface may be a dedicated screen, such as a TFT LCD screen, an IPS LCD screen, a capacitive touch screen LCD, an LED screen, an OLED screen, an AMOLED screen, or the like. In other embodiments, the user interface may include a wired or wireless communication protocol, such as bluetooth, BLE, Wi-Fi, 3G, 4G, 5G, LTE, etc., and may be configured to communicate the results of the analysis to an auxiliary device (e.g., mobile phone, tablet, computer, etc.) of the associated user via the communication protocol.

In a preferred embodiment, the target fluid stream is an air sample (or volume) taken from the vicinity of the reservoir being evaluated for possible insect infestation. In step S244, steps S232-S242 may be repeated by sampling multiple target fluid streams (e.g., air samples) from within multiple adjacent areas of the deposit to be evaluated. That is, the method 200 may also include identifying the source of the insect infestation, for example, by detecting a gradient of target VOCs of two or more target fluid streams (e.g., a first target fluid stream, a second target fluid stream, a third target fluid stream, etc.) at different distances from one or more stores.

In other embodiments of the method 200, the apparatus provided in step S204 may further comprise a controller operatively connected to the sensor array and the user interface, wherein the controller comprises a processor configured to perform one or more of the steps of the method 200 described above, and a memory configured to store one or more of the data types described above. Further, the memory may be configured to store instructions for performing one or more steps of the method 200.

In step S250, the method 200 may end.

These and other aspects of the apparatus used to implement the methods 100, 200 described herein may be more readily understood by reference to the following discussion and the various figures discussed therein.

Device and system

An apparatus and system for performing the above-described methods 100, 200 are disclosed herein. In particular, discussed herein are high sensitivity and high selectivity devices for detecting one or more target volatile organic compounds ("VOCs"), such as certain semiochemicals, kairomones and/or pheromones of various deposit insects ("SPIs"), within a target fluid stream. In addition, the devices and systems can be compact and light enough to be easily carried and hand-held.

Referring to fig. 3, a block diagram of an apparatus 300 and a system 302 configured to perform the methods discussed herein is shown, according to one embodiment of the present application. In particular, the device 300 includes a sensor array 304 having a plurality of VOC sensors 306. The plurality of VOC sensors 306 of the sensor array 304 may include about two to about ten VOC sensors, including three, four, five, and six VOC sensors. In particular embodiments, sensor array 304 may be enclosed in a chamber (or reactor) 308, wherein sensor 306 is exposed to (i.e., brought into contact with) a desired atmosphere within chamber 308. The chamber may have an inlet 310 configured to receive a fluid flow 314 from outside the chamber, and an outlet 312 configured to cause the chamber 308 to release a fluid flow 316.

As shown in fig. 4A and 4B, which illustrate a first side (fig. 4A) and a second side (fig. 4B) of a single VOC sensor 306 of a sensor array 304, the VOC sensor 306 may include a substrate 318 having a first side 320 and a second side 322. The substrate 318 may be, for example, a ceramic material, or may be alumina (Al)₂O₃) A wafer or a silicon wafer. In particular embodiments, substrate 318 may have an overall width of about 5mm to about 20mm, an overall height of about 4.3mm to about 20mm, and an overall thickness of about 0.32mm to about 0.65 mm. The VOC sensor 306 may be included on a substrate 318A resistive heater circuit formed on one side 320, a sense circuit 326 formed on second side 322 of substrate 318, and a chemically sensitive film 328 over sense circuit 326 on second side 322 of substrate 318.

Resistive heater circuits 324 may be formed on substrate 318 from heater circuit material using, for example, photolithography. In some implementations, the heater circuit material can include platinum. In particular embodiments, the heater circuit material may be a platinum ink including about 70 wt% to about 95 wt% platinum.

The heater circuit material may be, for example, lithographically patterned into a desired pattern on the substrate 318. In a particular implementation, the resistive heater circuit 324 of at least one of the plurality of VOC sensors 306 of the sensor array 304 can have a serpentine (i.e., meandering) pattern across a portion of the substrate 318. For example, in some embodiments, the warp wire width 330 of the resistive heater circuit 324 may be about 0.288mm to about 0.352 mm. In other embodiments, for example, the warp wire spacing 332 of the resistive heater circuit 324 may be about 0.333mm to about 0.407 mm. In still other embodiments, the wire height 334 of at least a portion of the resistive heater circuit 324 may be about 3.80mm to about 3.96mm, the external wire width 336 may be about 4.40mm to about 4.58mm, and the wire thickness (i.e., depth) may be about 0.19mm to about 0.24mm, including about 0.21 mm.

First side 320 of VOC sensor 306 substrate 318 may also include one or more terminals 338, 340. For example, as shown in fig. 4A, the first side 320 of the substrate 318 includes at least two terminals 338, 340 that are each operatively connected to a portion (e.g., opposing ends) 342, 344 of the resistive heater circuit 324.

Turning now to FIG. 4B, sensing circuitry 326 may be formed from sensing circuitry material on substrate 318 using, for example, photolithography. In some implementations, the sensing circuit material can include platinum. In particular embodiments, the sensing circuit material may include a platinum ink having about 70 wt% to about 95 wt% platinum.

The sensing circuit material may be, for example, photolithographically patterned into a desired pattern on the substrate 318. In a particular embodiment, sensing circuit 326 includes a first sensing element 346 and a second sensing element 348 forming a pair of extended interdigitated contacts (i.e., closely spaced alternating unconnected contacts). The first sensing element 346 can include a plurality of extended contacts 350, wherein each contact 350 has a latitudinal wire width 354 of about 0.162mm to about 0.198mm, a latitudinal wire spacing width 356 of about 0.738mm to about 0.902mm, and a wire thickness (i.e., depth) of about 0.19mm to about 0.24 mm. For example, the latitudinal wire width 354 of the contact 350 may be about 0.18mm, the latitudinal wire spacing 356 may be about 0.82mm, and the wire thickness may be about 0.21 mm.

Similarly, the second sensing element 348 may include a plurality of extended contacts 352, wherein each contact 352 has a latitudinal wire width 358 of about 0.162mm to about 0.198mm, a latitudinal wire spacing 360 of about 0.738mm to about 0.902mm, and a wire thickness (i.e., depth) of about 0.19mm to about 0.24 mm. For example, the latitudinal wire width 358 of the contacts 354 may be about 0.18mm, the latitudinal wire spacing 360 may be about 0.82mm, and the wire thickness may be about 0.21 mm.

In some embodiments, each of the first and second sensing elements 346, 348 may include at least three contacts 350, 352, and the latitudinal wire spacing 362 between each of the contacts 350, 352 of the first and second sensing elements 346, 348 is about 0.288mm to about 0.352mm, including about 0.32 mm. Further, the warp wire length 364 of each of the contacts 350, 352 may be about 3.0mm to about 4.0mm, including about 3.8 mm.

The second side 322 of the substrate 318 may also include one or more terminals 366, 368 that are operatively connected to a portion 370, 372 of the sensing circuit 326.

In addition, the contacts 350, 352 of the sensing circuit 326 may be coated with a coating composition to form the chemically sensitive membrane 328. In some embodiments, the coating composition can include a gel, and the film 328 can be formed by applying the coating composition to a portion of the substrate 318 (e.g., the portion covering the contacts 350, 352), and then drying and calcining the coating composition at an elevated temperature, such as from about 400 ℃ to about 900 ℃, including from about 500 ℃ to about 700 ℃.

In particular embodiments, film 328 may be a metal oxide film, such as tin oxide (SnO)₂) A semiconductor film. In such embodiments, the coating composition may comprise tin oxide produced using a water-based gel. In certain embodiments, by reference to SnCl₄Forming an acidic tin solution, and neutralizing the acidic tin solution to produce SnO₂Gelling to prepare a gel. Then, for example, by dissolving the aqueous SnO₂The gel is spin coated onto the sensor side 322 of the substrate 318, the sensor 306 is dried at a first temperature, and then calcined at a second temperature to form nanocrystalline SnO on the substrate 318₂And a membrane 328. In particular embodiments, the first temperature at which drying is performed is from about 100 ℃ to about 150 ℃, and may preferably be about 130 ℃. In other embodiments, the second temperature at which the calcination is carried out is from about 400 ℃ to about 900 ℃, and may preferably be from about 700 ℃ to about 800 ℃. Importantly, these temperature ranges produce a pore size distribution and particle size distribution in the chemically sensitive membrane 328 that can provide excellent sensitivity.

Due to the chemical structure of the target VOC and the operating conditions of each VOC sensor 306, the number of electrons available in the conduction band of the membrane 328 may be affected (i.e., increased or decreased) when the target VOC (e.g., marker gas) comes into contact with the chemically sensitive membrane 328. In particular embodiments, the one or more target VOCs may be a "reducing gas" that provides additional electrons to the conduction band of film 328, thereby reducing the resistance of film 328, which may then be measured as a change in conductance of film 328. Certain pheromones, semiochemicals and kairomones of interest may comprise a six-membered carbocyclic ring and one or more carbonyl groups (-C ═ O). This is the region of the molecule at excess electron density that is able to interact with semiconductor film 328, thereby contributing charge carriers to the conduction band of film 328 (i.e., reducing the resistance of film 328). The chemical structures of the two semiochemicals are shown in table 3 below:

TABLE 3 semiochemical/kairomones chemical Structure

In a preferred embodiment, the sensor array 304 includes a plurality of different VOC sensors 306. That is, the composition of one or more of the plurality of VOC sensors 306 is different and optimized for specific detection needs. For example, the coating composition used to form film 328 may include one or more catalysts or dopants (e.g., dopants) that may be added when preparing the gel coat composition. In some embodiments, the coating composition comprises a dopant. In some embodiments, the dopant can be, for example, a transition metal. For example, the dopant may be selected from the group consisting of: platinum; palladium; molybdenum; tungsten; nickel; ruthenium; and osmium. As a result of the addition of dopants to the film 328 of the VOC sensors 306, each VOC sensor 306 may be optimized for a given gas or target VOC. In particular embodiments, device 300 may include a plurality of VOC sensors 306, wherein at least one VOC sensor 306 is optimized for a particular gas or target VOC by adding a catalyst or dopant (i.e., dopant). In other embodiments, each VOC sensor 306 present in the device 300 is optimized for a particular gas or target VOC by adding a catalyst or dopant (i.e., dopant). For example, in particular embodiments, the sensor array 304 may include a first VOC sensor 306 optimized for IMM larva semiochemicals, a second VOC sensor 306 optimized for adult IMM semiochemicals, and up to three VOC sensors 306 optimized for potential interferents and/or background gases; however, other combinations and numbers of VOC sensors 306 are also contemplated. Potential interferents and/or background gases may include, for example, hydrocarbons, alcohols, esters, and/or aldehydes.

Each VOC sensor 306 of device 300 may be positioned within chamber 308 such that chemically sensitive membrane 328 can be exposed to a fluid flow entering chamber 308. Referring to fig. 5, in a particular embodiment, each VOC sensor 306 may be suspended in a holder 500, for example, using wire bonds 502, 504, 506, 50, 510, 512, to hold the sensor 306 and connect the respective sensor 306 terminals 340, 342, 366, 368 to contacts 514, 516, 518, 520, 522, 524 of the sensor holder 500.

With further reference to fig. 6, a side view of an apparatus 300 according to certain aspects of the present disclosure is shown. In particular, device 300 shows a sensor array 304, sensor array 304 including six VOC sensors 306 (not visible), which VOC sensors 306 are suspended within a chamber 308 by a sensor holder 500. Further, according to some embodiments, a portion 526 of each sensor holder 500 can operatively engage an adapter 528, the adapter 528 operatively connecting the holder 500 and the VOC sensor 306 to a circuit board 530 of the device 300, which enables, for example, power to be supplied to the VOC sensor 306 and measurements to be taken.

In other words, the sensor array 304 may be operatively coupled to a controller 374 configured to perform one or more steps of the method described above. In particular, the controller 374 may be configured to: heating one or more VOC sensors 306 of the plurality of VOC sensors 306 to at least a first operating temperature; measuring the conductance of one or more VOC sensors 306 of the plurality of VOC sensors 306; determining a set of conductance change values corresponding to each of the one or more VOC sensors 306 in contact with the fluid stream; and determining a concentration of the gas component of the one or more target VOCs within the fluid stream based on the set of conductance change values.

Returning to FIG. 3, additional components of infestation detection system 302 are described in accordance with aspects of the present application. A system 302 for identifying insect infestation of a deposit is provided, the system 302 including a sensor array 304 as previously described. Further, in particular embodiments, the system 302 includes a test chamber 308 enclosing the sensor array 304, an air delivery unit 376, and a controller 374 operatively connected to the air delivery unit 376 and the sensor array 304.

In various embodiments, the air transfer unit 376 may include a valve 378 for controlling fluid flow through the system 302, a pump 380 for retrieving (or drawing) a fluid flow from outside the system 302 and for delivering (or pushing) the fluid flow through the system 302, and a fluid flow sensor 382 for measuring an amount (e.g., volume) of fluid retrieved by the air transfer unit 376. In particular embodiments, the fluid flow sensor 382 may be a mass flow control valve or a differential pressure transducer. In other embodiments, the valve 378 and the pump 380 can be user-actuated. That is, an associated operator of the system 302 may direct (e.g., physically trigger) the recovery of the external fluid flow using the air delivery unit 376.

The air transfer unit 302 may also define a fluid flow path for fluid flow 384 from outside the system 302 to the flow 314 entering the inlet 310 of the device 300 and to the flow 316 exiting the outlet 312 of the device 300. Portions of the fluid streams 314, 316, 384 may be conveyed along a fluid stream conveyance, such as a polymer tube.

Further, the air transfer unit 376 may be operatively connected to the controller 374 such that the controller 374 may operate the air transfer unit 376 to take a fluid stream from the chamber 308 and deliver the fluid stream to the chamber 308, wherein the fluid stream may be in fluid contact with the VOC sensor 306. In particular embodiments, controller 374 may, for example, measure an amount (e.g., volume) of fluid flow entering system 302 and instruct air delivery unit 376 (e.g., pump 380 and/or valve 378) to stop drawing fluid (e.g., air) once the measured amount reaches a predetermined threshold. In some embodiments, the predetermined threshold is a volume sufficient for the device 300 to detect and measure the presence of one or more target VOCs in the fluid stream.

The controller 374 of the system 302 may be operatively connected to the air delivery unit 376 and the sensor array 304, and may include a processor and memory. The controller 374 may be further configured to: operating air transfer unit 376 to recover a fluid stream (e.g., fluid stream 378) from outside system 302 and deliver the fluid stream (e.g., fluid stream 314) to testing chamber 308, wherein the plurality of VOC sensors 306 are in fluid contact with fluid stream 314; operating the sensor array 304 to heat the one or more VOC sensors 306 to at least a first operating temperature and to measure the conductance of one or more of the plurality of VOC sensors 306; determining a set of conductance change values corresponding to each of the one or more VOC sensors 306; and determining a gas constituent concentration of the one or more target VOCs in the fluid stream 314 based on the set of conductance change values.

In some embodiments, the system 302 also includes one or more user interface components 380. User interface 380 may be operatively connected to controller 374, and controller 374 may be configured to operate user interface 380 to display and/or communicate to an associated user the results of a test conducted via system 302. The user interface 380 may be a dedicated display 382 visible to a user or operator of the system 302, such as a display including a TFT LCD screen, an IPS LCD screen, a capacitive touch screen LCD, an LED screen, an OLED screen, an AMOLED screen, or the like. In other embodiments, the user interface 380 may include a wired or wireless communication protocol 384, such as bluetooth, BLE, Wi-Fi, 3G, 4G, 5G, LTE, etc., and the user interface 380 may be configured to communicate the results of the analysis to an auxiliary device 386 (e.g., mobile phone, tablet, computer, etc.) of the associated user via the communication protocol.

The system 302 may also include a power supply 388, the power supply 388 being operatively connected to at least one of the air delivery unit 376, the device 300, the controller 374, and the user interface 380. The power supply 388 may be configured to deliver power to one or more components of the system 302, while the controller 374 may be configured to operate the power supply 388. In particular embodiments, power supply 388 may be integrated into system 302. In other embodiments, the power supply 388 may be a removable external accessory. In some embodiments, the power supply 388 may be a rechargeable power supply 388.

The various components of the described system will now be discussed in more detail with reference to fig. 7. As shown, fig. 7 illustrates a block diagram of a system 700 for identifying insect infestation of a storage by, for example, detecting the presence of one or more target VOCs and measuring the level of the one or more target VOCs 700. The system 700 includes a sense array 306, the sense array 306 including a controller 374, the controller 374 having a processor 702, a memory 704, and one or more input/output (I/O) interfaces 706, 708. The bus 710 may effectively connect the processor 702, the memory 704, and the I/O interfaces 706, 708 together. The memory 704 includes instructions 712 for performing one or more steps of the methods disclosed herein, and the processor 702 in communication with the memory 704 is configured to execute the instructions for performing the one or more steps.

As shown, the system 700 may also include a sensor array 304, the sensor array 304 including a plurality of VOC sensors 306, as well as an air delivery unit 376 and a user interface 380. Processor 702 may also control the overall operation of system 700, including the operation of sensor array 304, air delivery unit 376, and user interface 380.

Memory 704 may represent any type of non-transitory computer readable medium, such as Random Access Memory (RAM), Read Only Memory (ROM), magnetic disk or tape, optical disk, flash memory, or holographic memory. In one embodiment, memory 704 includes a combination of random access memory and read only memory. In some implementations, the processor 702 and the memory 704 may be combined in a single chip. Input/output (I/O) interfaces 706, 708 enable controller 374 to communicate with other components of system 700, such as sensor array 304, fluid flow sensor 382, air delivery unit 376, and user interface 380, via wired or wireless connections. The digital processor 702 may be embodied in various ways, such as by a single-core processor, a dual-core processor (or more generally by a multi-core processor), a digital controller, and cooperative method co-processors, digital controllers, and the like.

As used herein, the term "software" is intended to include any collection or set of instructions executable by a computer or other digital system for configuring the computer or other digital system to perform a task intended as software. The term "software" is intended to include such instructions stored in a storage medium such as RAM, hard disk, optical disk, etc., and is also intended to include so-called "firmware" as software stored on ROM, etc. Such software may be organized in various ways and may include software components organized as libraries, internet-based programs stored on remote servers and the like, source code, interpreted code, object code, directly executable code, and the like. It is contemplated that the software may invoke system level code or invoke other software residing on a server or other location to perform some function.

In various embodiments, instructions 712 of controller 374 may include, for example, conductance change module 714, specific net conductance ("SNC") data module 716, gas flow management module 718, operating temperature module 720, VOC concentration module 722, and report output module 724.

The conductance change module 714 may be configured to measure the conductance of one or more VOC sensors 306 of the sensor array 304 and record conductance data 728 in the memory 704. That is, in particular embodiments, the conductance change module 714 may be configured to instruct the processor 702 to measure the change in internal resistance of the chemically sensitive film 328 of the one or more VOC sensors 306 using the corresponding sensing circuit 326. Accordingly, the conductance change module 714 may be configured to measure and receive conductance signals from the VOC sensors 306 of the sensor array 304 via the I/O interface 706 and store the conductance as conductance data 728 in the memory 306. The conductance variation module 714 may also be configured to, for example, minimize electronic noise and conductance signal drift measured by the VOC sensor 306 to ensure accurate and precise measurements. In some embodiments, the conductance change module 714 may be configured to apply, for example, signal models and/or algorithms to manage or eliminate problems of conductance drift and electronic noise in the measurements of sensor conductance. In other embodiments, the conductance change module 714 may be configured to adjust the conductance value of the one or more VOC sensors by measuring the conductance of the VOC sensors and increasing and/or decreasing the operating temperature of the one or more VOC sensors (via the operating temperature module 720) until the conductance value of the VOC sensors matches a previously determined baseline conductance value.

As previously described, the SNC data module 716 may be configured to determine the specific net conductance ("SNC") of one or more VOC sensors 306 of the sensor array 304. In particular, SNC data module 716 and conductance change module 714 may be operable to measure and receive certain conductance signals (e.g., conductance values of a VOC sensor in contact with the control fluid stream and/or the sample fluid stream free of the target VOC) via I/O interface 706. The SNC data module may then determine a set of SNC values for the VOC sensors 306 and store the set of SNC values as SNC data 726 in the memory 704.

The air flow management module 718 may be configured to operate the air delivery unit 326 to recover a fluid flow (e.g., fluid flow 384), deliver the fluid flow to the device 300, and purge the fluid flow (e.g., fluid flow 316) from the system 302. In particular, the airflow management module 718 may be configured to receive airflow data 730 from a fluid flow sensor 382 of the air delivery unit 376 via the I/O interface 706. For example, the airflow data 730 may include fluid intake thresholds (e.g., volumes) and measurements from the flow sensor 382, which may be stored in the memory 704. In addition, the air flow management module 718 may be configured to operate the air delivery unit 376, including the valve 378 and the pump 380, as well as the inlet 310 and the outlet 312 that control the fluid flow path through the system 302.

The operating temperature module 720 can be configured to operate the heater circuit 324 of the VOC sensors 306 of the sensor array 304 via the I/O interface 706. In particular, the operating temperature module 720 can be configured to heat the one or more VOC sensors 306 to at least a first operating temperature and a second operating temperature by indicating the power applied to the heating circuitry 324 of the VOC sensor 306. The operating temperature module 720 may also be configured to monitor the temperature of each VOC sensor 306 of the sensor array 304 and adjust the power provided to adjust the operating temperature of the VOC sensor 306. The temperature module 720 may store the set point operating temperature of the VOC sensor 306 and the measured temperature as the temperature 732 in the memory 704.

As described above, the VOC concentration module 722 may be configured to determine a gas constituent concentration of one or more target VOCs in a fluid stream. The one or more target VOCs can be present in the fluid stream (e.g., air stream) in gaseous form. In particular embodiments, the one or more target VOCs are at least one of the following: a pheromone; a semiochemical; and kairomone. In other embodiments, at least one of the one or more target VOCs within the fluid stream may be selected from the group consisting of: 4, 8-dimethyldecanal; (Z, Z) -3,6- (11R) -dodecadien-11-olide; (Z, Z) -3, 6-dodecadienolide; (Z, Z) -5,8- (11R) -tetradecadien-13-olide; (Z) -5-tetradecene-13-lactone; (R) - (Z) -14-methyl-8-hexadecenal; (R) - (E) -14-methyl-8-hexadecenal; gamma-ethyl-gamma-butyrolactone; (Z, E) -9, 12-tetradecadienylacetate; (Z, E) -9, 12-tetradecadien-1-ol; (Z, E) -9, 12-tetradecadienal; (Z) -9-tetradecene acetate; (Z) -11-hexadecene acetate; (2S,3R, 1' S) -2, 3-dihydro-3, 5-dimethyl-2-ethyl-6 (1-methyl-2-oxobutyl) -4H-pyran-4-one; (2S,3R, 1' R) -2, 3-dihydro-3, 5-dimethyl-2-ethyl-6 (1-methyl-2-oxobutyl) -4H-pyran-4-one; (4S,6S,7S) -7-hydroxy-4, 6-dimethyl-3-nonanone; (2S,3S) -2, 6-diethyl-3, 5-dimethyl-3, 4-dihydro-2H-pyran; 2-palmitoyl-1, 3-cyclohexanedione; and 2-oleoyl-1, 3-cyclohexanedione. However, other pheromones, semiochemicals and kairomones are contemplated. The determined concentration of the target VOC of one or more of these target VOCs can be stored in memory as VOC data 734.

Report output module 724 may be configured to develop desired system outputs 738 and operate user interface 380 via I/O interface 380 to communicate outputs 738 to an associated user of system 302. In particular embodiments, user interface 380 may be a dedicated display or may be a secondary user device (e.g., a PC such as a desktop, laptop, palmtop, Portable Digital Assistant (PDA), server computer, cellular telephone, tablet computer, mobile device, etc., or combinations thereof). In some embodiments, the user interface 380 may include a speaker or speaker system. Thus, in some embodiments, I/O interface 708 may be a wired communication interface. In other embodiments, the I/O interface 708 may include wireless communication components and may generate communications with the user interface 380 via a wireless communication protocol such as bluetooth, BLE, Wi-Fi, 3G, 4G, 5G, LTE, or the like.

In any case, in various embodiments, a system output 738 such as, for example, a graph, chart, table, or dataset showing the determined VOC data may be communicated via the user interface 380. In some embodiments, the output 738 may include audible components, such as an audio tone, a set of tones, or an audible word, which may be communicated via a speaker or speaker system of the user interface 380. The audible output portion may be a tone that sounds at a frequency that varies based on the detected concentration of one or more gas components of the one or more target VOCs (e.g., increasing the frequency with higher detection levels). In particular embodiments, output 738 includes determining whether an insect infestation may be present within the storage. In other embodiments, output 738 may include an estimate of the likely cause of the infestation (e.g., identifying one or more specific SPIs based on the VOC data). In still other embodiments, output 738 may include recommendations for taking remedial action to preserve the value of the deposit, such as fumigation.