Detector inlet and method

Abstract

A method and apparatus are provided for providing a sample to a detector, the detector inlet for providing a sample to an analytical device for detecting a substance of interest comprising: a first sampling path configured to receive a first air flow containing a vapor for sampling by the analytical device; and a second sampling path configured to receive a second air flow, the second sampling path comprising a heater configured to heat aerosols present in the second air flow to vaporize the aerosols for sampling by the analytical device, the detector inlet operable to open and close each of the first and second sampling paths to allow at least one of the first and second air flows.

Description

[Technical field]

[0001] The present disclosure relates to detection methods and apparatus, more particularly to methods and apparatus for acquiring a sample for a detector, and even more particularly to methods and apparatus for providing samples of different forms to a detector. These methods and apparatus may find particular application in spectrometry, for example ion mobility spectrometry and mass spectrometry. [Background technology]

[0002] Some detectors, for example some types of ion mobility spectrometers, operate by "inhaling" a stream of gaseous fluid, such as air, into a detector inlet and sampling the air with an analytical device to detect substances of interest. The inhaled air stream can be sampled from the detector inlet using a sampling inlet, such as a pinhole, capillary, or membrane inlet.

[0003] Some analyzers, particularly some ion mobility spectrometers, are adapted for the analysis of vapors and gases. Such analyzers may be configured to detect substances of interest, such as narcotics, explosives, and chemical weapons. Thus, the detection sensitivity and reliability of such detectors may be a significant issue. Some substances of interest may include aerosols. In contrast to vapors or gases, aerosols include solid or liquid particles suspended in a gas. If a substance has a low vapor pressure, the ion mobility spectrometer may not be able to detect particles of that substance in the aerosol without vaporization of the aerosol.

[0004] In many cases, for example, for use by military and security personnel, handheld or portable devices may be required that require reduced size, weight, and complexity compared to other detectors. Typically, these devices are battery powered and it is desirable to extend their battery life. Summary of the Invention [Problem to be solved by the invention]

[0005] Aspects and embodiments of the present disclosure aim to address related technical problems. [Means for solving the problem]

[0006] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 shows a schematic diagram of the detector inlet. [Diagram 2] 2A-2C show schematic diagrams of a user-actuable cap for opening and closing the sampling pathway. [Diagram 3] FIG. 3 shows a schematic diagram of a detector comprising an ion mobility spectrometer coupled to a detector inlet. [Figure 4] FIG. 4 shows a schematic diagram of a detector with an analytical device including two spectrometers coupled to a detector inlet. [Diagram 5] FIG. 5 illustrates a method of operating the detector to detect a substance of interest. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In the drawings, like reference numbers are used to denote like elements.

[0009] An embodiment of the present disclosure relates to a detector inlet for providing a sample to an analytical device for detecting a substance of interest. Detectors such as mass spectrometers and ion mobility spectrometers may be configured to ionize a vapor and then analyze the ions generated from the vapor to detect a substance of interest. Such detectors may be configured to aspirate a flow of gaseous fluid from an environment to be tested and then take a sample from the flow. The sample can then be tested to detect the presence of a substance of interest. Gaseous fluids can include gases, e.g., air, vapors, and aerosols, e.g., solid or liquid particles suspended in the gaseous fluid.

[0010] Analytical devices configured to analyze vapor samples can directly analyze vapors present in the sampled environment. However, aerosols in the environment may need to be vaporized by heating the aerosol-containing air stream to facilitate satisfactory analysis of the vaporized aerosol. A heater can be placed in the path of the sample drawn into the inlet of the detector to heat the sample and vaporize the aerosol. However, when the heater is not operational, for example to sample vapors it is not necessary to power the heater, material may accumulate on the heater, causing contamination, and requiring a complete flush of the device while heating to desorb the contaminants. Conversely, when such a heater is activated during sampling of vapors in the environment, power is unnecessarily consumed. The sensitivity of the detector to detect vapors may also be reduced when the vapor sample is heated at the inlet of the detector.

[0011] Embodiments of the present disclosure relate to providing samples to an analyzer via multiple sampling paths that can be opened or closed to select the path through which the sample is provided to the analyzer. In particular, embodiments of the present disclosure relate to a detector inlet with separate sampling paths for sampling vapor and for sampling and vaporizing aerosol. Separate paths for sampling vapor and aerosol for provision to the analyzer can reduce the weight and size of the detector, e.g., a handheld detector, and can reduce power requirements by limiting heating of the inhaled sample.

[0012] Certain embodiments of the present disclosure relate to a detector inlet comprising a first sampling path configured to receive a first air flow containing vapor for sampling by an analytical device, and a second sampling path configured to receive a second air flow, the second sampling path comprising a heater configured to heat aerosols present in the second air flow to vaporize the aerosols for sampling by the analytical device. The detector inlet is operable to open and close each of the first and second sampling paths to allow at least one of the first and second air flows. Thus, when a sampling path is open, the detector inlet allows the air flow to enter the sampling path for sampling by the analytical device. Thus, the detector inlet can be controlled to provide samples to the analytical device based on the particular substances of interest to be detected, for example, different sampling paths can be selected depending on whether one or more substances of interest are known or likely to be present in the form of aerosols or vapors.

[0013] 1 shows a detector inlet 100 comprising a first sampling path 102 and a second sampling path 104 separate from the first sampling path 102. The first sampling path 102 is configured to receive a first air flow 112 for analysis by an analyzer 302 (not shown in FIG. 1). The second sampling path 104 is configured to receive a second air flow 114 and comprises a heater 106 configured to heat the second air flow 114 to vaporize aerosols present in the second air flow 114. In the embodiment shown in FIG. 1, the first sampling path is configured to receive vapors present in the external ambient environment for sampling by the analyzer, and the first sampling path does not include a heater.

[0014] The detector inlet 100 is operable to open and close each of the first and second sampling paths 102 / 104 to select at least one of the first and second sampling paths. For example, as shown diagrammatically in FIG. 1, the detector inlet may comprise a selector 120 for opening and closing the first and second sampling paths 102 / 104. The selector 120 may comprise one or more open portions 122 and one or more closed portions 124 that may be aligned with the first and second sampling paths 102 / 104 to selectively allow air from the environment to enter each sampling path. When a sampling path is aligned with an open portion, air can be drawn into the sampling path from the environment to be sampled, e.g., from the ambient environment in which the detector is located, and when a sampling path is aligned with a closed portion, air is not allowed to be drawn into the sampling path from the environment.

[0015] The detector inlet 100 may be operable to open and close each of the first and second sampling paths 102 / 104 to select either one of the first sampling path 102 only, the second sampling path 104 only, both the first sampling path 102 and the second sampling path 104, or both the first and second sampling paths 102 / 104.

[0016] As shown in FIG. 1, the selector 120 may be operable to occupy a number of positions 120a, 120b, 120c, and 120d to change the alignment of the open portion 122 and the closed portion 124 with the first and second sampling paths 102 / 104. In position 120a, both the first sampling path 102 and the second sampling path 104 are aligned with the closed portion 124, which may correspond when the detector inlet is not in use, for example, to prevent contamination of the detector. In position 120b, only the first sampling path 102 is aligned with the open portion 122, while the second sampling path 104 is aligned with the closed portion 124. When only the first sampling path 102 is open, the detector can save power by not having to operate the heater 106, which may be important in battery-powered or portable detectors, while also avoiding the buildup of contaminants on the heater. At position 120c, both the first sampling path 102 and the second sampling path 104 are aligned with the open portion 122, allowing for simultaneous sampling through both the first and second sampling paths 102 / 104. Thus, vapors in the first air stream 112 can be sampled and analyzed without being subjected to direct heating, while aerosols in the second air stream 114 can be simultaneously evaporated for analysis. Finally, at position 120d, only the second sampling path 102 is aligned with the open portion 122, while the first sampling path 104 is aligned with the closed portion 124.

[0017] 1 shows the selector 120 is operable to cycle through the open and closed configurations of the first and second sampling paths 102 / 104 by aligning the opening and closing portions 122 / 124, the first and second sampling paths 102 / 104 may be opened and closed in any suitable manner. For example, the sampling paths 102 / 104, or any additional sampling paths, may include separately actuable closure elements for opening and closing each sampling path.

[0018] In embodiments such as those shown in Figures 2A-2C, the detector inlet 100 may comprise a cap 200 configured to cover the respective inlets to the first and second sampling paths 102 / 104. The cap 200 may comprise, for example, a protective rain cap to cover and prevent ingress of contaminants or damage to the detector inlet when the portable or handheld detector is being transported. As shown in Figure 2, the cap 200 in some embodiments comprises a generally conical structure and may have the form of a frustum, although the shape of the cap is not limited and the cap may have any suitable shape and cross-section.

[0019] 2A-2C, the cap 200 may include a selector 120 and may be actuable by a user to control the opening of the first and second sampling paths 102 / 104. For example, the cap 200 may be actuable to open or close the first and second sampling paths 102 / 104 depending on its orientation, and in some embodiments may be user actuable by rotation of the cap to open or close the first and second sampling paths 102 / 104. The cap 200 shown in FIGS. 2A-2C includes a selector 120 with a plurality of opening portions 122 and closing portions 124, and is disposed over an inlet to the first sampling path 102 for receiving the first air flow 112 and an inlet to the second sampling path 104 for receiving the second air flow 114. In FIG. 2A, the inlets to the first and second sampling paths are aligned with the closing portion 124 of the selector 200 and the air flow to the first and second sampling paths 102 / 104 is blocked. In FIG. 2B, the cap 200 is rotated 60° so that the inlet 202 to the first sampling path 102 is aligned with the open portion 122 of the cap, allowing a first flow of air 112 into the first sampling path 102. In FIG. 2C, the cap 200 is rotated another 60° so that, in addition to the inlet 202, the inlet 204 to the second sampling path 104 is aligned with the open portion 122 of the cap, allowing a first air flow 112 and a second air flow 114 into the first sampling path 102 / 104, respectively. Although four closed portions 124 and two open portions 122 are shown in FIG. 2, it will be understood that in some embodiments, corresponding portions may be continuous and not defined by multiple separate portions. For example, in the embodiment shown in FIG. 2, the closed portion 124 may comprise a continuous closed portion extending around the cap 200 bounded by the two open portions 122, which in some embodiments may comprise a single continuous open portion.

[0020] Although Fig. 2 shows rotation of the cap 200 to open and close the first and second sampling paths 102 / 104, the actuation to control the opening and closing of the sampling paths need not be rotational. For example, the actuation may include linear movement of a cap or other user-operable selector to open and close the sampling paths, which may function by alignment of the opening and closing portions of the selector 120 as shown in Fig. 1, or in some embodiments may include actuation of individual closure elements or caps on each sampling path. In some embodiments, the selector may be separate from the cap, for example, a detector inlet may comprise a cap covering the inlet to the sampling paths and a separate selector, for example user-operable, to control the opening and closing of the sampling paths.

[0021] In an embodiment, the operation of the detector is controlled based on the configuration of the detector inlet 100, such as the open or closed state of the sampling inlet. For example, the detector inlet 100 may be configured to provide a signal to activate an analyzer when the first or second sampling path 102 / 104, or additional sampling paths, are open. Similarly, the detector inlet 100 may be configured to provide a signal to stop an analyzer when all sampling paths are closed, for example, when the first and second sampling paths 102 / 104 are closed. Thus, in an embodiment, the aforementioned cap 200 may be user-actuable to simultaneously select and open one or more sampling paths, provide a signal to activate an analyzer, and / or provide power to other parts of the detector, such as a user interface or control electronics. In an embodiment, the detector inlet 100 may be configured to provide a signal indicative of which sampling paths are open, for example to a controller of the detector.

[0022] As described above, the second sampling path 114 includes a heater 106. For example, the heater 106 may be disposed in or at least partially within the second sampling path 114, e.g., at an inlet to the second sampling path or at an outlet from the first conduit to the sampling volume. In some such examples, one or more interior walls of the second sampling path 104 may include a heater. The heater may include a conductor, such as a wire, that may be configured to be heated by resistive heating. The wire may include a metal. The heater 106 may be arranged as a grid or mesh to provide an obstacle in the inlet such that the second air flow 114 through the second sampling path 104 flows through or around the heater 106, e.g., a wire disposed in the path of the second air flow 114, such that the second air flow 114 must pass through the wire to reach the analyzer. In one example, the heater 106 includes a knitted structure, such as a wad or tangle of wires. One example of such a structure includes a knitted mesh of wires, such as a knitted mesh (RTM).

[0023] The grid or mesh structure may be arranged so that the wires occupy less than 80% of its volume, in some embodiments less than 60%, in some embodiments less than 40%, and in some embodiments less than 20% of the volume, with the remaining volume being an air layer through which the air to be heated can flow. In one embodiment, the structure is at least 60% air by volume, and in some embodiments, the structure is about 70% air by volume. The use of lower densities may improve the efficiency of the device and the sensitivity achieved by heating the airflow. If a woven or tangled wire structure, such as a knitted mesh (RTM), is used, the heater 106 may be wrapped around the outside of the structure. In some embodiments, the woven or tangled wire structure may be heated by passing an electric current through the structure. The heater 106 may provide a constriction in the second sampling path 104 or may be positioned around a constriction in the path of the second air flow 114. In some embodiments, the heater 106 may comprise an infrared source, such as an infrared lamp or LED, or an infrared laser. In some embodiments, the heater 106 may comprise a jet, or multiple jets, of hot air that is injected into the second air flow 114 in the second sampling path 104 before the air flow is provided to the analytical device for sampling.

[0024] 1 as parallel adjacent passages separated by a common interior wall, the first and second sampling paths 102 / 104, and / or any additional sampling paths, may be provided in other configurations. For example, different sampling paths may be aligned in different directions to provide flow to the analyzer from different directions, such as when the different sampling paths draw air from separate ports on the surface of the detector.

[0025] In an embodiment, the second sampling path 104 can include a trap for collecting aerosols when the heater 106 is off. The trap can include an obstacle positioned to capture aerosols in the second air stream 114, which can then be heated with the heater 106 to evaporate the aerosols collected on the trap. For example, the trap can include the heater 106. Thus, the trap can include a wire structure as described above (e.g., a woven or tangled wire structure such as a grid, mesh, or knit mesh (RTM)), which is configured to collect aerosols on the wire structure when the heater 106 is off.

[0026] As mentioned above, the detector inlet 100 can receive air to be sampled from the surrounding environment in which the detector is located. In some examples, a sample for analysis can also be collected on a sample swab by swabbing a surface and then provided to the detector for analysis. Thus, in some embodiments, the detector inlet 100 can be configured to receive a sample swab and provide a sample desorbed from the sample swab to an analysis device. For example, the detector inlet 100 can be configured to receive a sample swab and provide a sample desorbed from the sample swab to the first or second sampling path 102 / 104. In particular, a vapor sample desorbed from the sample swab can be provided to the first sampling path 102, for example, the detector inlet 100 can be configured to receive a sample swab such that the first air flow 112 to the first sampling path 102 must pass through the sample swab in order to pass through the first sampling path 102, for example, when the sample swab can be placed at the inlet of the first sampling path 102.

[0027] The detector inlet 100 may comprise a swab heater configured to heat a sample swab to desorb sample present on the sample swab. For example, the swab heater may be located upstream of the access to the first sampling access port 102. Alternatively or additionally, the detector inlet 100 may be configured to receive a probe, such as a sample collection wand, that comprises a swab heater and a sample swab. In some embodiments, the detector inlet may be configured to provide power to a swab heater on the probe, for example, the detector inlet comprises a coupling for providing power to a swab heater on the probe or an inductive coupling for inductively heating a swab or swab heater on the probe.

[0028] 1 and 2 show only the first and second sampling paths 102 / 104, in embodiments the detector inlet 100 may include one or more additional sampling paths to receive respective additional air flows for sampling by the analyzer. The detector inlet may also be operable to open and close the one or more additional sampling paths as described with respect to the first and second sampling paths 102 / 104. The one or more additional sampling paths may be adapted to receive different samples relative to the first and / or second sampling paths and / or may be adapted to process the sample differently within the additional paths.

[0029] In an embodiment, the one or more additional sampling paths may comprise a third sampling path for receiving a sample swab, and the detector inlet 100 is operable to open or close the third sampling path to allow a third flow of air into the third sampling path. The detector inlet 100 may be configured to receive a sample swab as described above, but instead of providing a desorbed sample from the sample swab to the first or second sampling path, a third sampling path may be provided for receiving a sample desorbed from the sample swab and providing the sample desorbed from the sample swab to an analytical device. In an embodiment, the third sample path may comprise a swab heater configured to heat the sample swab to desorb the sample for analysis by the analytical device. The swab heater may be positioned such that the third flow of air into the third sampling path must pass through a sample swab heated by the swab heater in order to pass through the third sampling path. For example, the swab heater may be entirely or at least partially within the third sampling path and detector inlet configured to allow a sample swab or probe containing a sample swab to be at least partially inserted into the third sampling path, and a third air flow is drawn past the sample swab to provide a desorbed sample to the analytical device. The detector inlet 100 may be operable to open and close the third sampling path to allow insertion of the sample swab and to allow the third air flow. In embodiments, the detector inlet may not include a swab heater, but may be configured to receive a probe with a sample swab, and the probe may include a swab heater. The detector inlet may provide power to a swab heater on the probe to desorb sample from the swab for sampling by the analytical device via the third sample path.

[0030] 3 shows an analytical device comprising a detector 300 with a detector inlet 100 and a spectrometer 302 having a sampling port 304 for obtaining a sample from a sampling volume 306 to the spectrometer 302 for analysis. The detector may be portable, for example a handheld detector, and may comprise a portable power source 328 that may be carried by the detector. The portable power source may comprise a battery, a fuel cell, a capacitor, or any other portable power source suitable for powering the detector.

[0031] 3 and 4, the first and second sampling paths 102 / 104 of the detector inlet 100 are configured to provide vapor or vaporized aerosol to a common sampling volume 306 from which an analyzer obtains samples for analysis through one or more sampling ports 304. The one or more sampling ports 304 may comprise a sampling inlet, such as a pinhole, capillary, or membrane inlet. In an embodiment, the one or more sampling ports 304 comprise one or more pinhole inlets.

[0032] In FIG. 3, the spectrometer 302 comprises an ion mobility spectrometer coupled to a sampling volume 306 by a sampling port 304 and comprising a reaction region 308 in which a sample can be ionized. The sampling port 304 is operable to obtain a sample from the sampling volume 306 into the spectrometer 302. A gate electrode 310 can separate the reaction region 308 from a drift chamber 312. The drift chamber 312 comprises a current collector 314 from the gate electrode 310 towards both ends of the drift chamber 312. In other embodiments, the ion mobility spectrometer can be operated with an ion trap to hold and release sample ions instead of the gate electrode 310. The drift chamber 312 also comprises a drift gas inlet 316 and a drift gas outlet 318 arranged to provide a flow of drift gas along the drift chamber 312 relative to the direction of movement of the sample ions towards the current collector 314, e.g., a flow of drift gas is provided from the current collector 314 towards the gate 310. The sampling port 304 is operable to sample air from the sampling volume 306 into the reaction region 308 of the spectrometer 302. The reaction region 308 includes an ionizer 320 for ionizing the sample. In the embodiment shown in FIG. 3, the ionizer 320 comprises a corona discharge ionizer comprising electrodes. The drift chamber 312 also comprises drift electrodes 322, 324 for applying an electric field along the drift chamber 312 to accelerate ions against the flow of drift gas towards the current collector 314. The detector may comprise a sampler (not shown) configured to sample a selected volume of fluid smaller than the sampling volume 306 through the sampling port 304 to provide the sample to the analyzer. The sampler may comprise an electromechanical actuator, e.g., a solenoid driven actuator, and / or a mechanical pump arranged to transport vapor from the sampling volume 304 through the sampling port 304 to the analyzer / spectrometer 302.

[0033] The detector 300 may include a flow provider for drawing air through the sampling path and past one or more sampling ports of the analytical device. As shown in FIG. 3, the detector 300 includes a flow provider 330 configured to draw air through the first and second sampling paths 102 / 104 into the sampling volume 306 and through the sampling port 304. The flow provider 330 may be configured to provide an exhaust flow 332 downstream of the sampling volume 306 and the sampling port 304. The flow provider may be provided, for example, by a pump, a fan, or any device suitable for drawing a flow of air through the sampling path and into the sampling volume 306 and the sampling port 304, such as a bellows. If such a flow provider is used, it may not be part of the detector in some cases and may be provided separately.

[0034] 3, the detector 300 can include a controller 326 configured to control the operation of the detector. For example, the controller can be coupled to control or electronically communicate with the heater 106, an analytical device such as a spectrometer 302, a flow provider 330, and the selector 120 / cap 200. The controller 326 can include a processor and a memory that stores instructions for the operation of the detector 300.

[0035] In operation of the detector 300, for example, in response to an activation signal and the sampling path being open, the controller 326 operates the flow provider 330 to draw one or more respective air flows through the open sampling path and into the sampling volume 306. The controller then operates the detector to draw the sample in the sampling volume 306 through one or more sampling ports 304 and into the analyzer / spectrometer 302 for analysis.

[0036] The controller 326 may be configured to turn on the detector in response to receiving a signal that one or more sampling paths are open, e.g., to operate an analyzer and / or to provide power to other components of the detector, such as a user interface. In some embodiments, the controller 326 may be powered in response to a signal that a sampling path is open.

[0037] In an embodiment, the controller 326 is configured to control the operation of the detector 300 based on the selected sampling path. For example, the controller 326 may be configured to control the operation of the detector 300 according to one or more detection protocols that are selected based on the open sampling path. The sampling path may be selected as a result of the controller receiving a signal that a sampling path is open. For example, the controller 326 may be configured to receive a signal from the selector 120 / cap 200 indicating which sampling path is open, for example based on the orientation of the selector 120 / cap 200. Although the selector 120 / cap 200 is shown in FIG. 3 as being linked to the controller 326, the detector inlet 100 may include means, such as one or more sensors, separate from the selector 120 / cap 200 to provide a signal to the controller 326 indicating which sampling path is open. Alternatively or additionally, the sampling path may be selected based on an indication from a user of which sampling path is required. In an embodiment, the controller 326 may control the opening and closing of the sampling paths to open only the selected sampling path, for example, the controller may be configured to control the selector 120.

[0038] In an embodiment, the controller is configured to receive an indication of which of the first and second sampling paths 102 / 104 are open (or selected to be open) and control operation of the heater based on whether the second sampling path is open. The controller 326 can be configured to power the heater 106 to heat the aerosol in the second sampling path 104 only when the second sampling path 104 is open. For example, the heater 106 can be powered in response to the second sampling path 104 being opened or in response to a signal that operates the detector to perform an analysis when the second sampling path 104 is opened. When the second sampling path 104 is closed, the detector can conserve power, for example, by avoiding the need to power the heater 106 when only vapor detection through the first sampling path 102 and / or sampling through an additional sampling path is required.

[0039] The controller 326 may be configured to control the heat output of the heater 106 to vary the temperature and / or timing of heating. In an embodiment, the controller 326 is configured to control the heater 106 and the flow provider 330 to desorb residues that have accumulated in the second sampling path 104 or on the heater 106. For example, the controller 326 is configured to operate the heater 106 for a first period of time while drawing air through the second sampling path 104 to allow desorbed material from the second sampling path 104 to exit the detector inlet 100 and the sampling volume 306. After the first period of time has elapsed, the flow provider continues to draw air through the heater 106 through the second sampling path 104 while the second air stream 114 drawn through the heater 106 is heated to vaporize aerosols in the second air stream 114 for sampling by the analyzer / spectrometer 302. To desorb residues, the heater 106 may be heated to a temperature of at least 150° C. The flow of air through the second sampling path 104 then flushes the desorbed material from the detector in preparation for testing the air sample. The heat output of the heater 106 during the sampling of the second air flow to the vaporized aerosol may be less than the heat output during the first period to desorb the residue. For example, the heater 106 may be controlled to reduce the power supplied to the heater 106, for example by switching it off after the first period and the second air flow 114 heated at a lower power, or while the heater is cooling. If the second sample path 104 is open simultaneously with another sample path, for example the first sample path 102, the controller may be configured to delay operation of the analyzer to analyze the sample from the first sample path 102 until after the first period during which the residue is desorbed from the second sample path 104 and the heater 106. In some embodiments, desorption of residue from the second sampling path 104 may be performed when only the second sampling path 104 is open, prior to opening any other sampling paths.

[0040] In some embodiments, the controller is configured to control the heater 106 to provide heat output after a sample containing aerosol is accumulated in the second sample path 104. For example, the second sampling path can include a trap to collect aerosol when the heater 106 is not heating, and the heater 106 can then operate to desorb the accumulated aerosol for sampling by the analysis device. The controller 326, for example, in response to receiving an indication that the second sampling path 104 is open and aerosol accumulation is required, operates the flow provider 330 to draw a flow of air into the second sampling path 104 (e.g., through the trap) for an accumulation time period without heating the trap to desorb the aerosol, and then controls the heater 106 to heat the trap to desorb the aerosol from the trap for analysis after the accumulation time period has elapsed. The trap can include any suitable device for accumulating aerosol from the air flow, such that the trap can be heated by the heater 106 to desorb the accumulated aerosol. For example, the trap can include a heater 106 such that capturing the aerosol includes accumulating the aerosol on the heater 106, such as on a heater including a wire mesh or grid as described above, through which a stream of air can pass to deposit the aerosol on the trap.

[0041] The detector may be operable by a user to select whether aerosol accumulation is required, and if there is no indication that aerosol accumulation is required when the second sampling path 104 is open, the controller 326 may control the heater 106 to evaporate the aerosol in the second air stream 114 without an accumulation step. In some embodiments, a trap and a heater for heating the trap (the trap may include a heater) may be located in the additional sampling path instead of the second sampling path 104, such that the controller 326 only controls the trap heater and flow provider to accumulate aerosol when the additional sampling path is open.

[0042] If the detector inlet 100 includes a third sampling path for receiving a sample swab as described above, the controller 326 may provide power to a swab heater at the detector inlet 100, or to a swab heater on a probe in response to the third sampling path being opened, or in response to receiving a signal that a swab or probe is positioned at the detector inlet 100 to provide a sample to the third sampling path. For example, the controller may be configured to provide power to the swab heater in response to insertion of a probe into the detector inlet 100. If heating of the sample swab is performed by, for example, a heated probe or an externally controlled heater on a sampling wand, the controller 326 may be configured to operate the flow provider 330 in response to receiving a signal that a swab is positioned to provide a sample to the third sampling path, for example in response to insertion of a probe.

[0043] In some embodiments, the trap for accumulating the aerosols described above may be separate from the detector, or may be an add-on component that can be placed at the detector inlet and heated to desorb the accumulated aerosols as described with respect to the sample swab. For example, the controller 326, in response to a signal to accumulate aerosols on the external trap, draws a flow of air through the trap and into the sampling path, accumulates the aerosols on the trap, and then provides heat to the trap to desorb the accumulated aerosols while drawing air (e.g., continuing to draw air) through the trap and into the sampling path of the detector inlet 100.

[0044] In an embodiment, the controller 326 is configured to control the flow provider 330 to draw air into at least one sampling path, through the sampling volume 306, past the sampling port 304, and through which a sample is aspirated by the analyzer. When a sampling path is open, operation of the flow provider 330 draws air, for example from the external ambient environment, into the sampling path and then into the sampling volume 306. The flow provider 330 then directs an exhaust flow 332 from the sampling volume 306, and the detector may be configured to exhaust the exhaust flow 332 away from the detector.

[0045] The controller may be configured to control the operation of the flow provider 330 based on the open sampling paths. For example, if multiple sampling paths are open, the flow provider 330 may be controlled to increase the flow rate based on the number of open sampling paths to maintain the flow through each individual sampling path above a threshold. If fewer sampling paths are selected, the power to the flow provider 330 may be reduced to conserve power. In some embodiments, the flow provider 330 is configured to provide a single flow rate regardless of which sampling paths are open. For example, the flow provider 330 may be configured to provide a single flow rate sufficient to draw air for sampling through all of the sampling paths that may be open simultaneously.

[0046] The sampling volume 306 is disposed between the sampling paths (e.g., the first and second sampling paths 102 / 104) and an outlet from which the exhaust flow 332 is extracted. For example, as shown in Figures 3 and 4, the sampling volume 306 may comprise a flow path configured to receive the sample-laden air flow from at least the first and second sampling paths 102 / 104 (and in some embodiments any additional air flow from additional sampling paths, e.g., the third sampling path discussed above) and convey the sample-laden air flow through the sampling port 304 to the exhaust 332.

[0047] The sampling paths or flow paths described herein are shown as an arrangement of conduits such as hoses or pipes. However, they may also be provided by channels and plenums cut into a block of material and then enclosed. In the embodiment shown in Figures 1, 3, and 4, the sampling path and / or flow path including the sampling volume may be less than 20 mm wide. For example, less than 10 mm wide, such as less than 5 mm, such as less than 2 mm, such as less than 1.5 mm, such as less than 1 mm, such as less than 0.75 mm, such as less than 0.5 mm, such as less than 0.4 mm, such as less than 0.3 mm, such as less than 0.2 mm, such as less than 0.1 mm. In the embodiment shown in Figures 1, 3, and 4, the sampling path and / or flow path including the sampling volume may be at least 10 microns wide, such as at least 0.1 mm wide. For example, at least 0.2 mm, such as at least 0.3 mm, such as at least 0.4 mm, such as at least 0.5 mm, such as at least 0.75 mm, such as at least 1 mm, such as at least 1.5 mm, such as at least 2 mm, such as at least 5 mm wide.

[0048] In some cases, the detector 300 may be used in the presence of dust and grit and other particulate matter. Such particulates may clog or otherwise damage or contaminate the detector. In an embodiment, the flow provider 330 is configured to draw a flow of air to be sampled through one or more sampling ports 304 of the analyzer to allow the detector 300 to sample vapors in the flow while drawing particulates present in the flow through the one or more sampling ports 304 without entering the one or more sampling ports 304. Although the analyzer is configured to sample vapors, some particulates or aerosols may nevertheless enter the sampling ports 304, but the sampling ports 304 may be configured to reduce the proportion of particulates or aerosols drawn through the sampling ports 304 when the vapors are sampled. As shown generally in FIGS. 3 and 4, the sampling ports 304 may be configured to draw the sample into the analyzer in a direction perpendicular to the direction of the bulk flow through the sampling volume 306 to the exhaust 332, reducing particles entering or blocking the sampling ports 304. In an embodiment, the detector may include one or more flow directors configured to change the distribution of particulates within the sampling volume to increase the proportion of particulates that pass through the sampling inlet without being drawn into the sampling inlet. For example, the flow director may include a change in the cross-section of the flow passage containing the sampling volume or a change in the direction of flow within the flow passage to provide a volume adjacent the sampling port 304 in which a reduced proportion of particulates are present. For example, the flow director may protrude from a wall of the flow passage and the sampling port 304 is located on the wall of the flow passage downstream of the flow director. Alternatively, the sampling port 304 may be located inside a bend in the flow passage or in the center of a circulating flow within the flow passage such that centrifugal effects reduce the proportion of particulates in the region adjacent the sampling port 304.

[0049] Although FIG. 3 shows an ion mobility spectrometer, the analyzer may comprise at least one of an ion mobility spectrometer (IMS), a differential mobility spectrometer (DMS), a mass spectrometer (MS), a chromatography device (e.g., a gas chromatography system), and an optical spectrometer (e.g., an infrared spectrometer or a Raman spectrometer). In some embodiments, the analyzer may include an ion mobility spectrometer, a mass spectrometer, or a combination of IMS-MS. The IMS may comprise a positive IMS and / or a negative mode IMS. In embodiments, the analyzer comprises both a positive mode IMS and a negative mode IMS configured to analyze samples from a single sample volume. In some embodiments, a single IMS may be switchable between positive and negative modes and may be configured to rapidly switch between positive and negative modes to analyze a single sample in both positive and negative modes.

[0050] The controller 326 may be configured to receive an indication from the analytical device that a substance of interest has or has not been detected, and to provide instructions to a user, such as providing an alert to the user that a substance of interest has been detected.

[0051] In some embodiments, the operating parameters of the analytical device and / or parameters for data analysis may be selected based on the open sampling paths. For example, if different sampling paths are intended to detect different substances of interest, the operating parameters of the analytical device, such as a spectrometer, may be controlled to enable or improve detection of the target substances. For example, if a sampling path is intended to detect a substance of interest that results in one or more specific peaks in the spectrum, the operating parameters of the spectrometer or the analysis of the resulting data may be controlled to focus on the relevant peaks and / or to exclude regions of the spectrum that are not associated with the expected substances of interest.

[0052] FIG. 4 illustrates a detector 300 as shown in FIG. 3, where the analyzer comprises two spectrometers 302 with two respective pinhole sampling ports 304. The two spectrometers 302 may include, for example, a positive mode IMS and a negative mode IMS. Although the two sampling ports 304 are illustrated in FIG. 4 as being separated along the bulk flow direction from the sampling path 102 / 104 to the exhaust 332, any suitable configuration may be used depending on the requirements and internal structure of the detector 300. For example, the two sampling ports 304 (and in an embodiment, the respective spectrometers 302) may be separated around the periphery or circumference of the flow path including the sampling volume 306, and may be substantially the same distance from the sampling path 102 / 104, for example, located on opposite sides of the flow path or adjacent to each other on the wall of the flow path and separated in a direction perpendicular to the bulk flow direction. Although not shown in FIG. 4 for clarity, it will be understood that a controller 326 and a portable power source 328 may be present as shown in FIG. 3, and that the controller 326 may be coupled to and control the operation of both spectrometers 302 in FIG. 4.

[0053] Although the devices illustrated in Figures 1-4 provide an embodiment of the present disclosure, other embodiments are contemplated.

[0054] 5 illustrates a method 500 of operating a detector to detect a substance of interest in a sample, the detector including multiple sampling paths for providing samples to an analytical device for analysis. As shown in FIG. 5, the method includes receiving 502 a signal to operate the detector and receiving 504 an indication of which of the multiple sampling paths has been selected. As described herein, the indication that the respective sampling path is selected may be provided when the respective sampling path is opened. Alternatively, the indication may be provided by other means, such as a user input, in which case the method may include operating the detector to open the selected sampling path and close the non-selected sampling path.

[0055] In an embodiment, the method may include selecting 505 one or more detection protocols to be associated with the selected sampling path. The detection protocol may include instructions for controlling operation of the detector, and each sampling path is associated with one or more detection protocols for controlling operation of the detector. In an embodiment, the detection protocol may be selected based on a particular combination of different sampling paths that are selected together.

[0056] The method includes drawing one or more respective air streams only through the selected sample path and providing a sample in the one or more respective air streams for sampling by an analytical device, at step 506. The sample is analyzed with the analytical device to detect the substance of interest, at step 510. The method may include providing an indication, e.g., a warning, to a user that the substance of interest was or was not detected.

[0057] In an embodiment, the multiple sampling paths include a first sampling path 102 configured to receive a first air flow 112 including vapor for sampling by an analyzer, and a second sampling path 104 configured to receive a second air flow 114, the second sampling path 104 including a heater 106 configured to heat aerosols present in the second air flow 114 to vaporize the aerosols for sampling by the analyzer, and the method includes heating the second sampling path 104, e.g., providing power to the heater 106 only if the second sampling path 104 is selected. For example, the method may include receiving an indication that the second sampling path 104 is open, then selecting an aerosol detection protocol associated with the second sampling path, and operating a detector according to the protocol to heat the air flow 114 in the second sampling path to vaporize the aerosols. In an embodiment, the aerosol detection protocol may include heating the heater 106 while drawing air through the second sampling path 104 to desorb residues in the second sampling path 104, as previously described herein.

[0058] If the detector includes a sampling path including a trap for accumulating aerosol and a heater for heating the trap to desorb the accumulated aerosol, the method may include collecting aerosol on the trap when the sampling path including the trap is open while the heater is off, then heating the trap to vaporize the aerosol collected on the trap, and providing the vaporized aerosol to an analyzer.

[0059] The sampling path that includes the trap may be a second sampling path 104 that includes a heater 106, e.g., the heater 106 includes a trap. When the second sampling path 104 is selected, the method may include receiving an indication (e.g., based on user input) of whether accumulation of the aerosol before heating is required, and in response to the indication, controlling the detector 300 to vaporize or accumulate the aerosol as described above. In some embodiments, the method may separately include (i) accumulating and evaporating the aerosol from the trap, and (ii) heating the aerosol in the air stream as the aerosol passes through the second sampling path 104, with two separate corresponding sampling and analysis steps being performed by the analysis device.

[0060] In an embodiment, the method may include receiving an indication that a sample swab has been placed at the detector inlet 100 and drawing air into a sampling path at the detector inlet while being heated to desorb the sample for analysis. In response to the indication that a sample swab or a probe containing the sample swab has been placed at the detector inlet 100, the method may include heating the sample swab to desorb vapor, for example, by operating a swab heater at the detector inlet or by providing power to a heater on the swab or swab probe.

[0061] It will be appreciated that the detector referred to in relation to the present methods may comprise, for example, detector 300 as shown in Figures 1-4, and the methods may comprise controlling detector 300 as previously described herein based on one or more selected sampling paths. For example, the methods may include operation of detector 300 using controller 326 as described herein. For example, the methods may be implemented by controller 326 according to instructions stored in a memory of controller 326.

[0062] The controller 326 described herein may be provided by any suitable control logic, such as analog control circuitry and / or a digital processor, examples include field programmable gate arrays, FPGAs, application specific integrated circuits, ASICs, digital signal processors, DSPs, or by software loaded into a programmable processor. Aspects of the present disclosure may comprise computer program products, which may be recorded on a non-transitory computer readable medium, which may be operable to program a processor to perform any one or more of the methods described herein.

[0063] Although embodiments of the present disclosure are described as having particular application in ion mobility spectrometers, the described apparatus and methods may be applied to other analytical systems requiring testing of vapors, such as vapors associated with aerosols having low vapor pressures.

[0064] As will be appreciated, a vapor may contain a substance in its gas phase at a temperature below its transformation point. In contrast to a vapor or gas, an aerosol contains fine particles of a solid or liquid suspended in a gas. As used herein, the term "vaporization" is used to mean the conversion of at least a portion of a substance from a solid or liquid to a vapor or gas.

[0065] Apparatus features described herein may be provided as method features and vice versa.

[0066] It should also be understood that certain combinations of the various features described and defined in any aspect of the invention may be implemented and / or provided and / or used independently. Other embodiments and variations will be apparent to those skilled in the art in the context of this disclosure.

Claims

1. A detector inlet for supplying a sample to an analytical instrument for detecting a target substance, wherein the detector inlet is as follows: A first sampling path configured to receive a first airflow containing vapor for sampling by the analytical device; and A second sampling path configured to receive a second airflow, the second sampling path comprising a heater configured to heat aerosols present in the second airflow to evaporate the aerosols for sampling by the analyzer; Equipped with, The detector inlet is operable to open and close each of the first and second sampling paths in order to allow at least one of the first and second airflows. Detector entrance.

2. The detector inlet according to claim 1, wherein the detector inlet is operable to open and close each of the first and second sampling paths to open only the first sampling path, open only the second sampling path, open both the first and second sampling paths, and close both the first and second sampling paths.

3. The detector inlet according to claim 1 or 2, wherein the detector inlet is configured to provide a signal for operating the analyzer in response to the opening of the first or second sampling path, and / or to provide a signal for shutting down the analyzer in response to the closing of the first and second sampling paths.

4. The detector inlet according to claim 1 or 2, wherein the detector inlet comprises a cap configured to cover the respective inlets to the first and second sampling paths, the cap being user-operable to control the openings of the first and second sampling paths.

5. The detector inlet according to claim 4, wherein the cap is user-operable by rotation of the cap in order to open and close the first and second sampling paths.

6. The detector inlet according to claim 1 or 2, wherein the first and second sampling paths are configured to provide a vapor or vaporized aerosol to a common sampling volume from which the analyzer draws a sample for analysis through one or more sampling ports.

7. The detector inlet according to claim 6, wherein the one or more sampling ports include one or more capillary inlets, membrane inlets, or pinhole inlets.

8. The detector inlet according to claim 1 or 2, wherein the detector inlet is configured to receive a sample swab and provide the sample detached from the sample swab to the analyzer, and for example, the detector inlet is configured to provide the sample detached from the sample swab to the first sampling path.

9. The detector inlet according to claim 8, wherein the detector inlet is equipped with a swab heater configured to heat a sample swab and desorb the sample present on the swab, or the detector inlet is configured to receive a probe comprising the swab heater and the sample swab.

10. The detector inlet according to claim 1 or 2, comprising one or more additional sampling paths for receiving each additional airflow for sampling by the analyzer, wherein the detector inlet is operable to open and close the one or more additional sampling paths.

11. The detector inlet according to claim 10, wherein the one or more additional sampling paths comprises a third sampling path for receiving a sample swab, for example, the third path comprising a swab heater configured to heat the sample swab for desorbing the sample for analysis, or the detector inlet is configured to supply power to a swab heater on a probe comprising the sample swab.

12. The detector inlet according to claim 1 or 2, wherein the heater configured to heat an aerosol comprises a wire arranged in the path of the second airflow such that the second airflow must pass through the wire to reach the analyzer.

13. A detector comprising a detector inlet according to claim 1 or 2, and an analytical device configured to receive a sample from the detector inlet.

14. The detector according to claim 13, further comprising a controller configured to control the operation of the detector based on the open sampling path, for example, the controller receiving an instruction on whether the first or second sampling path is open, and being configured to control the operation of the heater based on whether the second sampling path is open.

15. The detector according to claim 14, wherein the controller is configured to supply power to the heater to heat the aerosol only when the second sampling path is opened.

16. A detector according to claim 14, wherein the controller is configured to draw in air through the second sampling path, allowing substances desorbed from the second sampling path to exit the detector inlet, while after the first period, the heater is operated during the first period to draw in the second airflow through the second sampling path, thereby evaporating the aerosols in the second airflow for sampling by the analyzer.

17. A detector according to claim 13, wherein the second sampling path comprises a trap for collecting aerosols when the heater is off, and for example, the trap comprises the heater.

18. The detector according to claim 17, wherein the detector is operable to draw in air passing through the trap, for example, through the trap, and the heater is turned off to collect aerosols on the trap, and then turned off to heat the trap to evaporate the collected aerosols.

19. The detector according to claim 13, comprising a flow provider configured to draw air through one or more sampling ports of the analyzer via the first and second sampling paths, for example, the flow provider being configured to draw in a flow to be sampled through the one or more sampling ports of the analyzer, thereby enabling sampling of vapor in the flow while drawing in particles present in the flow without entering the one or more sampling ports.

20. The detector according to claim 13, wherein the analytical apparatus includes at least one of an ion mobility spectrometer, a differential mobility spectrometer, a mass spectrometer, a chromatography apparatus, or an optical spectrometer.

21. A method for operating a detector for detecting a target substance in a sample, wherein the detector comprises a plurality of sampling paths for providing the sample to an analyzer, and the method includes the following steps: A step of receiving a signal to operate the detector and receiving an indication of which of the multiple sample paths has been selected, and A process of drawing out one or more airflows through only selected sample pathways and providing the sample to one or more airflows for analysis by an analytical instrument.

22. The method according to claim 21, comprising operating the detector to open a selected sampling path and close an unselected sampling path, or providing an indicator that a sampling path has been selected when each sampling path is opened.

23. The method according to claim 21 or 22, comprising controlling the operation of the detector according to one or more detection protocols, wherein the one or more detection protocols are selected based on the selected sampling path.

24. The method according to claim 21 or 22, comprising: a first sampling path configured to receive a first airflow containing vapor for sampling by the analyzer; and a second sampling path configured to receive a second airflow, wherein the second sampling path includes a heater configured to heat aerosols present in the second airflow in order to evaporate the aerosols for sampling by the analyzer, and the method comprises supplying power to the heater only when the second sampling path is selected.

25. A method according to claim 24, comprising collecting an aerosol on a trap in the second sampling path when the heater is off, and then heating the trap to evaporate the aerosol collected on the trap.

26. A computer program product configured to program a detector controller to perform the method described in claim 21 or 22, or a logic circuit configured to control a detector to perform the method described in claim 21 or 22.

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