Detector inlet device and method

Abstract

An entry device for a detection system and a method of operating a detection device are provided. The inlet device comprises: an inlet for receiving a flow of air to be measured, the inlet comprising a first heater configured to vaporize an aerosol carried by air for sampling by an analysis device; and a trap configured to collect the aerosol from the airflow and vaporize the collected aerosol for sampling by the analysis device, wherein the inlet device is configured to provide a flow of air to be measured to (i) the first heater to enable aerosol in the flow of air to vaporize for sampling by the analysis device, and (ii) the trap to collect aerosol on the trap while the flow of air is provided to the first heater.

Description

[0001] This disclosure relates to detection methods and detector inlet devices, more specifically to methods and inlet devices for acquiring samples for a detector, and even more specifically to methods and inlet devices for supplying vaporized aerosols to a detector. These methods and devices are particularly applicable to spectroscopic methods, such as ion mobility spectrometry and mass spectrometry.

[0002] Detectors, such as certain types of ion mobility spectrometers, can be operated by "drawing" a gaseous fluid (e.g., air) into the detector inlet and sampling that air with an analytical device to detect the substance of interest. The drawn-in airflow can be sampled from the detector inlet using a sampling port (e.g., an orifice, capillary, or membrane inlet).

[0003] Some analytical devices, particularly ion mobility spectrometers, are suitable for analyzing vapors and gases. Such devices can be configured to detect substances of interest, such as anesthetics, explosives, and chemical warfare agents. The reliability and capability of such detectors to detect any significant quantities of these agents can therefore be a significant issue. Some substances of interest may include aerosols. Compared to vapors or gases, aerosols contain fine solid or liquid particles suspended in a gas. If the vapor pressure of a substance is low, an ion mobility spectrometer may be unable to detect particles of that substance in an aerosol without vaporizing it.

[0004] Aerosols can be collected on a pre-concentrator for subsequent desorption and analysis. However, this requires a time delay between sampling from the test environment and receiving the analytical results.

[0005] The aspects and embodiments disclosed herein are intended to solve the aforementioned technical problems. Summary of the Invention

[0006] Embodiments of this disclosure relate to an inlet device for a detection system, used to provide a sample to an analytical apparatus for the detection of a substance of interest. Detectors, such as mass spectrometers and ion mobility spectrometers, may be configured to ionize vapor and then analyze the ions generated from the vapor to detect the substance of interest. Such detectors may be configured to draw in a gaseous fluid stream from the test environment and then collect a sample from that stream. These samples can then be tested to detect the presence of the substance of interest. The gaseous fluid may include gases, such as air, vapor, and aerosols, such as solid or liquid particles suspended in the gaseous fluid.

[0007] Analytical devices configured to analyze vapor samples can directly analyze vapors from the sampled environment. However, aerosols in the environment may require vaporization by heating the air stream containing the aerosols in order to perform satisfactory analysis of the vaporized aerosols.

[0008] Aerosols can be vaporized as air flows from the environment to the detector, for example, by a heater located in the detector inlet along the path of the sample drawn into the detector inlet. This allows for simultaneous real-time monitoring of aerosols and vapors without the need for pre-concentration and desorption for analysis. However, when aerosols are present at low concentrations, particularly when aerosol particles are present at low number densities, small amounts of such aerosols may be difficult to detect reliably due to insufficient concentration or the inherent inability to synchronize aerosol vaporization with the unknown arrival time of low-number-density aerosol particles. Low-concentration aerosols can be collected on a trap until a sufficient amount is available for analysis. However, this does not allow for real-time monitoring of higher concentrations of aerosols. Similarly, while using a heater in the detector inlet to vaporize aerosols entering the inlet allows for real-time monitoring, low-concentration aerosols are vaporized without sufficient concentration for reliable detection and cannot be collected on an aerosol trap because they have already vaporized.

[0009] Embodiments of this disclosure aim to address these problems by controlling the flow in the detector inlet, vaporizing the aerosols entering the inlet for analysis, allowing real-time analysis of aerosols in the test airflow, and simultaneously collecting the aerosols on a trap to allow for the collection and subsequent analysis of low-concentration aerosols in the airflow. Therefore, real-time monitoring of vapors and aerosols can be performed simultaneously with the provision of trapping for the detection of low-concentration aerosols. In this way, a single detection device can provide low-concentration aerosol analysis without sacrificing the ability to detect higher concentrations of aerosols and vapors in real time.

[0010] The aspects of this disclosure are set forth in the independent claims, and optional features are set forth in the dependent claims. The aspects of this disclosure may be provided in combination with each other, and features of one aspect may be applied to the other aspects.

[0011] This article discloses two specific aspects relating to the structure of an entry device configured to solve the technical problem under discussion.

[0012] One aspect provides an inlet device for a detection system, the device comprising: An inlet for receiving the airflow to be measured, the inlet including a first heater configured to vaporize air-borne aerosols for sampling by the analytical device; The trap is configured to collect aerosols from an air stream and vaporize the collected aerosols for sampling by an analytical device. A first flow path includes the first heater and one or more sampling ports located downstream of the first heater, through which the analysis device can obtain samples from the inlet; A second flow path, including the trap, is configured to provide the airflow to be measured; A first flow provider is configured to allow a first portion of the airflow to flow along the first flow path from the first heater through the one or more sampling ports; and A second flow provider is used to cause a second portion of the airflow to flow through the trap along the second flow path.

[0013] It will be understood that the first flow path and the second flow path are separate. In this way, the inlet device allows aerosols to be collected on the trap by diverting a second portion of the airflow into the second flow path, while also allowing aerosols in the first portion of the airflow to be vaporized and sent to the analyzer for analysis along with the vapor present in the airflow. Therefore, it is possible to collect low-concentration aerosols while simultaneously allowing real-time analysis of both aerosols and vapors in the air being tested.

[0014] Another aspect provides an inlet device for a detection system, the device comprising: An inlet for receiving the airflow to be measured, the inlet including a first heater configured to vaporize air-borne aerosols for sampling by the analytical device; The trap is configured to collect aerosols from an air stream and vaporize the collected aerosols for sampling by an analytical device. The flow path has a first end and a second end, the first end being configured to receive the airflow to be measured; One or more sampling ports, through which the analytical device can acquire samples from the inlet, the one or more sampling ports being arranged between the first heater and the second end, such that aerosol flowing from the first end to the second end through the inlet can be vaporized by the first heater and provided to the one or more sampling ports; The trap is arranged between the one or more sampling ports and the second end, such that aerosols carried by the airflow through the first heater and through the one or more sampling ports are collected on the trap.

[0015] In this configuration, aerosols can be vaporized as they pass through the first heater for sampling and analysis via one or more sampling ports, and when the heater is not operating, the aerosols can be collected on a trap via the heater and one or more sampling ports. Therefore, by intermittently operating the heater, aerosols can be supplied to the trap for collection to allow for the detection of low concentrations, and also analyzed as they enter the inlet.

[0016] Nevertheless, it will be understood that the concepts addressed in this disclosure can generally be implemented in a variety of different ways in addition to these specific configurations.

[0017] Therefore, in one aspect, an inlet device for a detection system is provided, the device comprising: an inlet for receiving a test airflow, the inlet including a first heater configured to vaporize air-borne aerosols for sampling by an analytical device; and a trap configured to collect aerosols from the airflow and vaporize the collected aerosols for sampling by the analytical device; wherein the inlet device is configured to provide the test airflow to: (i) the first heater to vaporize aerosols in the airflow for sampling by the analytical device, and (ii) the trap to collect aerosols on the trap while the airflow is provided to the first heater.

[0018] What will be understood is that supplying the airflow to be measured to a heater (which vaporizes aerosols as the air passes through the inlet) and simultaneously supplying the airflow to a trap allows for real-time analysis of aerosols in the environment by vaporizing the aerosols, while also allowing for the collection of aerosols on the trap to enable the detection of low concentrations of aerosols that might not be reliably detectable upon entry through online vaporization. In this way, low concentrations of aerosols can be collected to allow for reliable analysis without inhibiting the detection of aerosols containing the substance of interest during the period of low-concentration aerosol collection.

[0019] The inlet device can be configured to transfer a portion of the airflow to be tested into a second flow path, so that the aerosol can be collected in the second flow path, while the aerosol is also allowed to pass along a first flow path, in which the aerosol can be vaporized when it passes through a first heater.

[0020] Therefore, in a preferred embodiment, the inlet includes: a first flow path including the first heater and one or more sampling ports located downstream of the first heater, through which the analytical device can acquire samples from the inlet; a second flow path including the trap; a first flow provider for causing a first portion of the airflow to flow along the first flow path from the first heater through the one or more sampling ports; and a second flow provider for causing a second portion of the airflow to flow along the second flow path through the trap. It will be understood that "downstream" refers to the direction along the first flow path from the first heater to the one or more sampling ports, and similarly, "upstream" refers to the direction along the first flow path from the one or more sampling ports to the first heater.

[0021] The second flow path may extend upstream of the first flow path from the one or more sampling ports. For example, the inlet may include a common inlet portion configured to receive the airflow to be measured, wherein the common inlet portion branches into the first flow path and the second flow path upstream of the one or more sampling ports. The first flow path may include a continuation of the common inlet, while the second flow path extends laterally from the first flow path; for example, the inlet may have a constant cross-sectional area between the common inlet and the first flow path.

[0022] Typically, when referring to a flow path, it may suitably include a conduit having one or more walls configured to contain fluid within the conduit in order to guide the fluid along the flow path, for example, where the flow path is defined by one or more walls of the conduit. Thus, a conduit may comprise a closed channel for guiding and containing fluid traveling along a given flow path.

[0023] The first flow path may be defined by a first conduit configured to guide a first portion of the airflow through the first heater and then through the one or more sampling ports configured to provide a sample to the analytical device through the wall of the first conduit.

[0024] Therefore, the inlet may suitably include one or more sampling ports through which the analytical device can be configured to acquire samples. For example, the one or more sampling ports may be independently selected from a via, a capillary inlet, or a membrane inlet. The analytical device may be configured to acquire samples from the inlet in any suitable manner, such as by pulse-operated sampler (e.g., a pump) to extract samples from the inlet through the one or more sampling ports.

[0025] The second flow path may be defined by a second conduit that branches off from the first conduit at a junction upstream of one or more sampling ports, wherein a trap is disposed at the junction of the first and second conduits to collect aerosols present in a second portion of the airflow entering the second conduit, while allowing aerosols in a first portion of the airflow to pass through the first conduit.

[0026] The second flow path may be separated from the first flow path by the trap. For example, the trap may extend across the inlet from the first flow path to the second flow path, such that aerosols entering the second flow path must pass through the trap.

[0027] Suitable, the trap is arranged such that when the second flow provider is turned off, or when the second flow provider provides a reverse flow from the trap into the first flow path, vaporized aerosols from the trap can enter the first flow path for sampling at the one or more sampling ports. For example, the trap may be located in the second flow path adjacent to the first flow path, such that even when no flow from the first flow path into the second flow path is provided, aerosols vaporized from the trap diffuse into the first flow path and can be carried along the first flow path to the one or more sampling ports.

[0028] The configuration of the trap in the second flow path allows aerosol material to be collected upstream of the trap, for example, such that the aerosol is collected on the side of the trap facing the first flow path. Therefore, when the aerosol material vaporizes from the trap, it is already concentrated on the side of the trap closest to the one or more sampling ports, which facilitates the delivery of the vaporized aerosol material from the trap to the first flow path and to the one or more sampling ports.

[0029] The first heater can be arranged downstream of the second flow path in the first flow path, for example, downstream of the inlet (e.g., a node) of the second flow path, such that a second portion of the airflow is provided to the trap without passing through the first heater. This configuration allows the first heater to be operated without interfering with the collection of aerosols on the trap. In an embodiment, the first heater can alternatively be arranged upstream of the inlet of the second flow path, and the first heater can operate in a pulsed mode to provide heating intermittently. Thus, when the heater is off, the aerosol can pass through unvaporized and be collected on the trap. With the first heater operating in pulsed mode, the analyzer can be configured to synchronize the sampling of vaporized aerosols through the one or more sampling ports with the operation of the first heater to provide vaporized aerosols from the first heater to the analyzer.

[0030] The inlet device can operate in a first mode and a second mode. In the first mode, the first heater is operated to vaporize aerosols carried by a first portion of the airflow for sampling by the analytical device, and wherein aerosols carried by a second portion of the airflow are collected on the trap. In the second mode, aerosols collected on the trap are vaporized for sampling by the analytical device.

[0031] In the first mode, the first flow provider and the second flow provider can operate simultaneously to provide a first portion of the airflow along the first flow path and a second portion of the airflow along the second flow path. Therefore, in the first mode, the first flow provider and the second flow provider operate simultaneously to divide the airflow to be measured into a first portion passing along the first flow path and a second portion passing along the second flow path.

[0032] In the second mode, the inlet device is operable such that when the second flow provider is closed or operated in reverse, aerosols collected from the trap vaporized in the trap enter the first flow path and are supplied by the first flow provider to the one or more sampling ports. As described above, in the second mode, vapors desorbed from the trap can diffuse into the first flow path, for example, when the second flow provider is closed, and then be carried along the first flow path to the one or more sampling ports by the operation of the first flow provider. Alternatively, in the second mode, the second flow provider can be operated to provide reverse flow along the second flow path, such that fluid flows along the second flow path, through the trap, into the first flow path, and reaches the one or more sampling ports.

[0033] The flow providers mentioned herein, such as the first or second flow providers, can typically be provided by a pump, fan, or any other suitable means for providing airflow through the inlet along a given flow path.

[0034] In a further embodiment, the inlet device can be configured to allow the airflow to be tested to pass through along a common flow path (e.g., a single duct or closed channel). Therefore, this configuration can be provided as an alternative to the previously described configuration in which the airflow to be tested is allocated into the first and second flow paths.

[0035] Therefore, in another preferred embodiment, the inlet defines a flow path having a first end and a second end, the first end being configured to receive the airflow to be measured, the inlet including: one or more sampling ports through which the analytical device can acquire a sample, the one or more sampling ports being arranged between the first heater and the second end such that aerosols flowing from the first end to the second end through the inlet can be vaporized by the first heater and provided to the one or more sampling ports; wherein, the trap is arranged between the one or more sampling ports and the second end such that aerosols carried by the airflow through the first heater and through the one or more sampling ports are collected on the trap.

[0036] It will be understood that the various elements of the inlet device may still be as defined herein, for example, with reference to the conduits, flow paths and flow providers described above.

[0037] The inlet may suitably include a conduit configured to receive and guide the airflow to be measured along the flow path.

[0038] The inlet device may include a flow provider operable in a first mode to provide a first flow from the first end to the second end through the inlet, and in a second mode to provide a second flow from the second end to the first end through the inlet. In one embodiment, the flow provider may include a first flow provider and a second flow provider, the first flow provider operable to provide the first flow from the first end to the second end through the inlet, and the second flow provider operable to provide the second flow from the second end to the first end through the inlet. Alternatively, the flow provider may include a single flow provider configured to provide both the first flow and the second flow, for example, wherein the flow provider is operable to provide bidirectional flow, such as providing flow in a first direction and in the opposite direction.

[0039] The first heater is suitably operable in the first mode to provide intermittent heating, for example, the first heater may be operable in a pulse mode to provide intermittent heating so as to allow the aerosols in the first portion to pass through the first heater unvaporized for collection on the trap. In the second mode, the trap is suitably operable to vaporize the collected aerosols, the vaporized aerosols being carried by the second flow for sampling by the analytical device through the one or more sampling ports.

[0040] Therefore, in the first mode, the inlet device is configured to intermittently operate the first heater to provide vaporized aerosol for the analyzer to sample, while also collecting unvaporized aerosol that has passed through the first heater on the trap when the first heater is turned off (e.g., between each pulse of operating the first heater).

[0041] It will be understood that, since the trap is arranged between the one or more sampling ports and the second end, a second portion of the airflow supplying aerosols to the trap reaches the upstream side of the trap closest to the one or more sampling ports. Thus, the aerosols collected on the trap are collected on the side of the trap facing the one or more sampling ports, which can increase the proportion of aerosols reaching the one or more sampling ports when vaporized aerosols travel from the trap to the one or more sampling ports for sampling, because they do not need to pass through the trap structure to reach the one or more sampling ports.

[0042] Typically, when referring to a heater, this can include one or more individual heating elements or a single device. For example, a heater can include conductors, such as one or more elongated conductors, for instance, wires that can be arranged to heat the object being heated by resistance. The elongated conductors can include metal. The heater can be arranged in a grid or mesh to provide an obstruction in the flow path, causing air flowing through or around the heater. Typically, a heater, such as a first heater, preferably includes an array of wires or elongated conductors arranged in the path of the airflow in the flow path, such that the airflow must pass through the wires or elongated conductors to reach the analytical apparatus.

[0043] For example, the first heater preferably includes a conductor arranged across the inlet, such that the airflow to be measured passes between the conductors. For instance, the first heater includes an array of elongated conductors or wires extending across the inlet, such as a grid or parallel array of elongated conductors. The elongated conductors can extend from one wall of a duct defining a flow path across the flow path to the opposite wall of the duct. The wires or elongated conductors can be manufactured by any suitable means, including providing the elongated conductors of the first heater by etching a metal substrate.

[0044] A first heater may be arranged within the inlet or at least partially within the inlet; for example, one or more inner walls of the inlet may include the first heater. It will be understood that the first heater is suitably configured such that vaporized aerosols pass through the first heater along a corresponding flow path in which the heater is arranged.

[0045] Typically, the first heater may include an array of elongated conductors (e.g., wires), such as parallel conductors, or an array of elongated conductors following a curved or meandering path (e.g., a zigzag path) across the inlet. In a preferred embodiment, the first heater may be configured to allow fluid to pass through the first heater while minimizing the capture of aerosols and vapors on the heater. The first heater may include elongated conductors, such as resistance heating wires, arranged across the inlet in a flow path through the inlet (e.g., extending across the inlet perpendicular to the flow direction through the inlet). The first heater may include an array of elongated conductors arranged across the inlet, such as an array of elongated conductors arranged in a plane perpendicular to the flow direction through the inlet. The thickness of the conductors (e.g., wires) and the spacing between the conductors may be selected to minimize aerosol capture on the first heater. The first heater may include more than one array of conductors, such as more than one array of conductors arranged in corresponding planes offset from each other in the flow direction. In other embodiments, the first heater may include a braided structure, such as a coil of wire or a wire winding. One embodiment of such a structure includes a braided wire mesh, such as a wire mesh (RTM).

[0046] The first heater structure can be arranged such that the conductor occupies 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 by the conductor of the first heater, with the remaining volume occupied by an air space through which heated air can flow. In one embodiment, the first heater structure is at least 60% air by volume, and in some embodiments, the first heater structure is approximately 70% air by volume. Using a lower density can improve the efficiency of the device and the sensitivity achieved by heating the airflow. The heater can provide a contraction zone in the second sampling path, or it can be arranged around a contraction zone in the second airflow path. In some embodiments, the first heater can include an infrared source, such as an infrared lamp or LED, or an infrared laser. In some embodiments, the first heater can include one or more jets of hot air injected into the flow path.

[0047] The first heater can be configured to heat the airflow to a temperature of at least 150°C to vaporize the aerosol, such as at least 200°C, and / or wherein the heater is configured to heat the airflow to a temperature not exceeding 300°C, such as not exceeding 250°C. Therefore, the heater can be configured to heat the airflow to a temperature between 150°C and 300°C, such as between 200°C and 250°C.

[0048] Typically, the trap may suitably include a second heater for vaporizing the collected aerosols. The second heater may have any suitable configuration to allow heating the trap to vaporize the aerosols.

[0049] A trap can include any suitable structure or material for collecting aerosols from an airflow passing through it. A trap is typically a filter configured to allow gases and vapors to pass through while collecting aerosols in the form of liquid or solid particles. For example, a trap can include a fiberglass material, such as glass wool. Fiberglass materials like glass wool have been found to effectively collect aerosol substances while allowing vapors to pass through, providing selective trapping of the aerosol of interest without interference from vapors that may be analyzed separately while the aerosols are collected in the trap.

[0050] It will be understood that the trap is separate from the first heater, so that heating the first heater does not vaporize the aerosols collected on the trap.

[0051] Collection of aerosols on a trap appropriately includes any method in which aerosol material is immobilized on the trap for subsequent vaporization. For example, aerosol material may be deposited on the surface of a material constituting the trap (e.g., glass fiber), and solid or liquid aerosol material may be deposited on the surface of the trap material to immobilize the collected aerosols for subsequent vaporization.

[0052] As described herein, the inlet device is configured to operate in a first mode for real-time detection of aerosols in the airflow under test and in a second mode for detection of aerosols collected on the trap.

[0053] Therefore, in one aspect, an inlet device for a detection system is provided, the device comprising: an inlet for receiving a stream of air to be tested, the inlet including a first heater configured to vaporize aerosols carried by the air for sampling by an analytical device; and a trap configured to collect aerosols from the air stream and vaporize the collected aerosols for sampling by the analytical device; wherein the inlet device is operable in the first mode and the second mode, in the first mode, operating the first heater to vaporize aerosols carried by a first portion of the air stream for sampling by the analytical device, and wherein aerosols carried by a second portion of the air stream are collected on the trap; in the second mode, aerosols collected on the trap are vaporized for sampling by the analytical device.

[0054] The inlet device may, for example, include an air movement device comprising one or more ducts configured to receive and guide a first portion and a second portion of the airflow; and one or more flow providers, wherein the trap, the first heater, and the one or more flow providers are arranged in the one or more ducts to provide the first mode and the second mode.

[0055] It will be understood that any element of the entry device in this respect may be substantially as defined herein.

[0056] Another aspect provides a detection device, including an inlet device as defined above and an analytical device configured to acquire a sample from the inlet to detect a substance of interest.

[0057] The analytical apparatus may include any suitable analyzer for detecting the substance of interest in vapor form. The analytical apparatus may include at least one of ion mobility spectrometry (IMS), differential ion mobility spectrometry (DMS), mass spectrometry (MS), chromatographic apparatus (e.g., a gas chromatography system), and optical spectrometry (e.g., an infrared spectrometer or a Raman spectrometer). In embodiments, the analytical apparatus may include an ion mobility spectrometer, a mass spectrometer, or a combination of IMS-MS. The IMS may include positive mode IMS and / or negative mode IMS. In embodiments, the analytical apparatus includes both positive mode IMS and negative mode IMS, configured to analyze a sample from a single sampling volume. In some embodiments, a single IMS can switch between positive and negative modes and can be configured to switch rapidly between positive and negative modes to analyze a single sample in both positive and negative modes. The analytical apparatus preferably includes an ion mobility spectrometer (IMS).

[0058] The detection device can be portable, such as a handheld detector, and may include a portable power source that can be carried by the detector. The portable power source may include a battery, fuel cell, capacitor, or any other portable power source suitable for providing power to the detector.

[0059] The detection device can be suitably configured to draw the analyte airflow from the surrounding environment of the detector into the inlet. For example, the detection device can be configured to detect the substance of interest in the ambient air surrounding the detector operation (rather than drawing the analyte fluid from another device (such as a chromatography device) or a pre-collected sample). For example, the detection device can include a housing configured to house the inlet device and the analysis device, wherein the detection device is configured to draw the analyte airflow from the ambient air outside the housing.

[0060] The detection device may include a controller configured to control the operation of the detection device. For example, the controller may be configured to operate the detection device in either a first mode or a second mode as described herein. The controller may be configured to alternately operate the detection device in the first mode and the second mode multiple times, for example, wherein the detection device operates in the first mode for most of the time to detect the presence of the substance of interest in real time, and intermittently operates in the second mode after a specified time period to analyze aerosol substances deposited on the trap.

[0061] Typically, the analytical device can be operated to sample vapor regardless of whether the aerosol is being vaporized by the first heater or the trap. For example, the detection device can operate in a third mode in which neither the first heater nor the trap is heated, and vapor present in the test airflow is sampled for analysis. The device can operate in the third mode when neither the first heater nor the trap is heated. For example, the device can be configured to operate in the third mode whenever the first heater and the trap are not heated. The device can operate in the third mode at any time during which the device is not operating in either the first or second mode. For example, in the case of intermittent operation of the first heater as described elsewhere herein, the device can operate in the third mode during the intervals of intermittent heating of the first heater. The device can be configured to sample vapor, for example, while the aerosol is being collected on the trap. Therefore, in the case of intermittent operation of the first heater, the first mode can further include sampling vapor present in the test airflow for analysis.

[0062] The controller can be configured to receive information from the analysis device indicating whether the substance of interest has been detected or not, and to provide that indication to the user, such as providing an alarm to the user that the substance of interest has been detected.

[0063] The controller may be suitably configured to synchronize the operation of the analytical apparatus with the operation of the flow feeder, the first heater and / or the second heater to obtain vaporized aerosol samples supplied to the analytical apparatus from the first heater or the trap, for example, in a first mode or a second mode.

[0064] Another aspect provides a method for operating a detection device to analyze vapors and aerosols, the method comprising: during a first time period, operating the detection device in a first mode to: provide a stream of air to be tested to an inlet of the device; heating a first portion of the air stream to vaporize aerosols carried by the first portion of the air stream for sampling by the analysis device, while simultaneously collecting aerosols carried by a second portion of the air stream on a trap; and during a second time period, operating the detection device in a second mode to: vaporize the collected aerosols from the trap for sampling by the analysis device.

[0065] As described regarding the inlet device, one exemplary way of implementing this disclosure is to split the airflow to be tested into a first portion and a second portion, such that one portion can be analyzed while the aerosol is being collected on a trap. Therefore, in a preferred embodiment, in the first mode, the airflow to be tested is split into the first portion and the second portion by guiding the first portion along a first flow path through a first heater and then through one or more sampling ports (through which the analytical device acquires samples), and guiding the second portion along a second flow path including the trap, the second flow path extending upstream of the one or more sampling ports from the first flow path.

[0066] In the second mode, the collected aerosols can be vaporized from the trap and provided along a first flow path to one or more sampling ports for sampling by the analytical device. For example, a reverse flow is provided from the second flow path through the trap into the first flow path, or the trap separates the first flow path from the second flow path, and the aerosol material vaporized from the trap enters the first flow path (e.g., by diffusion) and is carried to one or more sampling ports by an airflow along the first flow path.

[0067] In the first mode, the first portion may be provided by a first flow provider arranged in the first flow path, passing through the first heater and then through the one or more sampling ports, and the second portion may be provided to the trap by a second flow provider arranged in the second flow path.

[0068] In the first mode, the analytical device can be operated to sample and analyze aerosols vaporized by the first heater, while the aerosols are collected on a trap. In the second mode, the analytical device can be operated to sample and analyze aerosols collected from the trap vaporization.

[0069] As described regarding the inlet device, another exemplary manner of implementing this disclosure is to allow a portion of the airflow to pass through a first heater to a trap downstream of one or more sampling ports, thereby allowing aerosol material to be collected on the trap while also allowing the aerosol to be vaporized for analysis. Thus, in another preferred embodiment, in the first mode, the airflow to be tested is provided along a flow path, passing through a first heater for vaporizing aerosols in the airflow, then through one or more sampling ports from which an analytical device obtains a sample for analysis, and finally reaching the trap. For example, the flow path may be provided by a conduit having walls configured to receive and guide the airflow along the flow path.

[0070] In the first mode, the aerosol carried by the first portion of the airflow can be vaporized by the first heater for sampling through the one or more sampling ports, wherein the first heater is operated intermittently during the first time period, and when the heater is turned off, a second portion of the airflow passes through the first heater to provide the aerosol to the trap.

[0071] In the second mode, a reverse flow can be provided along the flow path, through the trap, and then through the one or more sampling ports for sampling by the analysis device.

[0072] In the first mode, the operation of the analytical device can be synchronized with the operation of the first heater to sample aerosols vaporized by the first heater through one or more sampling ports, and in the second mode, the operation of the analytical device can be synchronized with the vaporization of aerosols collected on the trap to sample aerosols vaporized from the trap through one or more sampling ports.

[0073] The method may include alternating between operating in a first mode and then in a second mode multiple times. This allows for real-time detection of aerosols while also intermittently collecting low-concentration aerosols for analysis.

[0074] In the first mode, the airflow to be tested can be intermittently heated to vaporize aerosols, and the analytical device can be operated to acquire samples from the airflow without heating it, to sample the vapors present in the airflow. Therefore, the method may include operating the detection device during periods when neither the airflow to be tested nor the trap is heated, and sampling the vapors present in the unheated airflow to be tested for analysis.

[0075] It will be understood that the detectors mentioned in the method may include the detectors or entry devices described elsewhere herein, and the method may include controlling the detector or entry device as previously described herein. For example, the method may include operating the detector or entry device using a controller as described herein. For example, these methods may be implemented by the controller according to instructions stored in the controller's memory.

[0076] The controllers described herein can be suitably provided by any appropriate control logic, such as analog control circuitry and / or digital processors, including field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), digital signal processors (DSPs), or provided via software loaded into a programmable processor. Aspects of this disclosure include computer program products, which may be recorded on a non-transient computer-readable medium, and these may be operable to program a processor to perform any or more of the methods described herein.

[0077] Another aspect provides a computer program product configured to program a controller of a detection device to perform the methods disclosed herein, or a fixed logic circuit configured to control the detection device to perform the methods disclosed herein. Attached Figure Description

[0078] Embodiments of this disclosure will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1A A schematic diagram of the detection device is shown, which includes an ion mobility spectrometer coupled to an inlet device operating in a first mode; Figure 1B A schematic diagram of the detection device is shown, which includes an ion mobility spectrometer coupled to an inlet device operating in a second mode; Figure 2A A schematic diagram of the detection device is shown, which includes an ion mobility spectrometer coupled to an alternative inlet device operating in a first mode; Figure 2B A schematic diagram of the detection device is shown, which includes an ion mobility spectrometer coupled to an alternative inlet device operating in a second mode; Figure 3 A schematic diagram of a detection device including two sampling ports is shown; and Figure 4 The method of operating the detection device is shown.

[0079] In the accompanying drawings, the same reference numerals are used to indicate the same elements. Detailed Implementation

[0080] This disclosure relates to a detector inlet, which includes a heater for vaporizing aerosols therein as the airflow to be analyzed reaches the analysis apparatus through the inlet, and a trap for collecting aerosols from the airflow.

[0081] Figure 1A A detection device 100 is shown, comprising an inlet 102 for receiving a test airflow 104. The inlet includes a first flow path 108 defined by a first conduit 109 and a second flow path 110 defined by a second conduit 111. The first conduit 109 and the second conduit 111 are closed flow paths defined by walls, receiving and guiding fluid flow along the first flow path 108 and the second flow path 110. The inlet 102 includes a common inlet portion 112, which includes a conduit for receiving the test airflow 104 and supplying it to the first flow path 108 and the second flow path 110.

[0082] At node 106, inlet 102 branches into a first flow path 108 and a second flow path 110. (Example) Figure 1AAs shown, in the first mode, the first flow provider 114 and the second flow provider 116 (each flow provider including, for example, a fan or any other suitable air movement device) operate simultaneously to draw airflow 104 along both the first flow path 108 and the second flow path 110. Figure 1A As shown, the flow passing through the first flow provider 114 and the second flow provider 116 is supplied to the exhaust port 130 from the detection device.

[0083] The second flow path 110 includes a trap 118 at the inlet of the second flow path 110 / second conduit 111. The trap 118 separates the second flow path 110 from the first flow path 108 by extending across the diameter of the second conduit 111 at a junction 106 between the first flow path 108 and the second flow path 110. The trap 118 may, for example, include a glass fiber structure that allows vapors and gases to pass through while trapping solid and liquid aerosol particles. The trap 118 may, for example, include glass wool.

[0084] A first heater 120 is disposed in a first flow path 108, downstream of the second flow path inlet and the trap 118. The first heater 120 is arranged to extend across a first conduit 109 such that, when the first heater 120 is operated, aerosols present in the airflow 104 passing through the first flow path 108 are vaporized and carried to a sampling port 122 downstream of the first heater 120. The sampling port 122 is configured to obtain a sample for analysis from a sampling volume 124 adjacent to the sampling port 122 in the first flow path 108. The first heater 120 may, for example, comprise an array of elongated conductors extending in diameter across the first conduit 109.

[0085] In such Figure 1A In the first mode shown, a first portion of the airflow to be measured is drawn in by a first flow provider 114 and passes through a first heater 120 along a first flow path 108. The first heater 120 is operated to heat and vaporize the aerosol present in the first portion of the airflow, and the vaporized aerosol reaches the sampling volume 124 along the first flow path 108 so that it can be sampled by the spectrometer 302 through the sampling port 122.

[0086] Also in the first mode, the second portion of the airflow to be tested is drawn in by the second flow provider 116 and enters the second flow path 110. The second portion of the airflow passes through the collector 118, and the aerosols present in the second portion of the airflow are collected on the collector 118.

[0087] A first heater 120 is arranged in the first flow path 108, located at the inlet of the second flow path 110 and downstream of the trap 118. This allows for the collection of aerosols on the trap 118 while the first heater 120 is operated to vaporize the aerosols for sampling through the sampling port 122. In an alternative embodiment, the first heater may be arranged upstream of the trap 118 in the inlet 102. In this case, the first heater 120 can operate intermittently to provide vaporized aerosols along the first flow path 108 for sampling, and during the intermittent periods when the first heater is not operating, the aerosols flow through the heater 120 and can be collected on the trap 118. It will be understood that when the first heater 120 is upstream of the trap 118, the aerosols are vaporized by the first heater 120 when the first heater 120 is operating and can pass through the trap 118 without being trapped. When the first heater 120 is not heating, the device can also be operated to sample vapors from the first flow path 108 through the sampling port 122. This saves electricity associated with powering the first heater 120 (for vaporization and aerosol detection) while maintaining continuous detection of vapor in the air stream under test.

[0088] Therefore, in such Figure 1A In the first mode shown, aerosols are collected on trap 118 and simultaneously vaporized by first heater 120 for sampling through sampling port 122. This allows low-concentration aerosols to be enriched on trap 118 without interrupting real-time analysis of aerosols in the test airflow 104.

[0089] Figure 1B The operation in the second mode is shown. Figure 1A The detection device. In the second mode, the trap 118 is heated by a second heater, which is arranged to heat the trap material to vaporize the aerosol material collected on the trap 118. The second flow provider 116 operates in reverse to provide a reverse flow along the second flow path 110, opposite to the operation in the first mode, while the first flow provider 114 maintains the flow along the first flow path 108 from the first heater 120 through the sampling port 122. The vaporized aerosol from the trap 118 is thus carried into the first flow path 108 for sampling through the sampling port 122. Although Figure 1B The second flow provider 116 is shown operating in reverse, but it will be understood that in the second mode, the second flow provider may alternatively not operate, in which case the aerosol material vaporized from the trap 118 may diffuse into the node 106 and then be carried along the first flow path 108 for sampling through the sampling port 122.

[0090] exist Figure 1A / 1B and Figure 2AIn / 2B, the analytical apparatus is shown as spectrometer 302, which includes an ion mobility spectrometer coupled to a sampling volume 124 via a sampling port 122. Spectrometer 302 includes a reaction region 308 in which a sample can be ionized. The sampling port 122 can be operated to obtain a sample from the sampling volume 124 into spectrometer 302. A gate electrode 310 can separate the reaction region 308 from a drift chamber 312. The drift chamber 312 includes a collector 314 facing the end of the drift chamber 312 opposite to the gate electrode 310. In other embodiments, the ion mobility spectrometer can be operated instead of the gate electrode 310 using an ion trap for holding and releasing sample ions. The drift chamber 312 also includes a drift gas inlet 316 and a drift gas outlet 318, the drift gas outlet 318 being arranged to provide a drift gas flow along the drift chamber 312 opposite to the direction of movement of the sample ions toward the collector 314, for example, a drift gas flow from the collector 314 toward the gate 310. Sampling port 122 can be operated to sample air from sampling volume 124 into reaction zone 308 of spectrometer 302. Reaction zone 308 includes an ionizer 320 for ionizing the sample. Figure 1A / 1B and Figure 2A In the embodiment shown in / 2B, ionizer 320 includes a corona discharge ionizer, which includes electrodes. Drift chamber 312 also includes drift electrodes 322, 324 for applying an electric field along drift chamber 312 to resist drift gas flow and accelerate ions toward collector 314. Detector may include a sampler (not shown) configured to draw a selected volume of fluid (smaller than sampling volume 124) through sampling port 122 to provide a sample to the analysis device. Sampler may include electromechanical actuators, such as solenoid-driven actuators, and / or mechanical pumps arranged to transfer vapor from sampling volume 124 through sampling port 122 into analysis device / spectrometer 302.

[0091] Figure 2A A detection device 200 is shown, which includes an inlet 202 for receiving a test airflow 204. The inlet includes a single conduit 212 configured to receive and guide the test airflow 204 through the inlet 202 to an exhaust port 230. Figure 2A As shown, inlet 202 / conduit 212 has a first end 240 and a second end 250, the first end 240 being configured to receive the airflow to be measured 204, and the exhaust flow from the second end 240 being shown as being supplied to the exhaust port 230.

[0092] A first heater 220 is disposed at a first end 240 of inlet 202. The first heater 220 is arranged to extend across conduit 212 such that when the first heater 220 is operated, aerosols present in the airflow 204 passing through the inlet are vaporized and carried to a sampling port 222 downstream of the first heater 220. This sampling port 222 is configured to acquire a sample from a sampling volume 224 adjacent to the sampling port 222 in inlet 202 for analysis. The first heater 220 may, for example, comprise an elongated array of conductors extending in diameter across inlet 202.

[0093] Inlet 202 also includes a trap 218 at the second end 250, such that when the flow provider 214 is in Figure 2A In the first mode of operation shown, the airflow to be measured 204 passes through the first heater 220, then through the sampling port 222, and reaches the trap 218. The trap 218 extends across the diameter of the inlet 202 and is configured to collect aerosols in the airflow reaching the exhaust port 230. The trap 218 may, for example, include a glass fiber structure that allows vapors and gases to pass through while capturing solid and liquid aerosol particles. The trap 218 may, for example, include glass wool.

[0094] Figure 2A The operation of the detection device 200 in a first mode is schematically illustrated, wherein the flow provider 214 is operated to provide the test airflow 204 through the first heater 220, through the sampling port 222, and then to the trap 218. The first heater 220 is operated to heat and vaporize the aerosols present in the test airflow 204. The vaporized aerosols then enter the sampling volume 224 along the inlet 202, and the analysis device (spectrometer 302) acquires the sample from the sampling volume 224 through the sampling port 222.

[0095] In the first mode, the first heater 220 operates in a pulsed manner to provide heating intermittently. Therefore, when the first heater 220 is operating, vaporized aerosols in the airflow 204 are sampled for analysis, as described above. Furthermore, during the time intervals between heating pulses of the first heater 220, when the first heater is not heating the inlet airflow 204, the aerosols in the airflow 204 pass unvaporized through the first heater 220 and are supplied to the trap 218 along the inlet 202, where they are collected. Therefore, through... Figure 2A The configuration shown operates the first heater 220 in a pulsed manner, which allows for real-time sampling of vaporized aerosols in the airflow 204, while also allowing aerosols present in the airflow 204 at low concentrations (or low number densities) to accumulate on the trap.

[0096] like Figure 2BAs shown, in the second mode, the flow provider 214 provides a reverse flow from the second end 250 of the inlet 202 to the first end 240. Simultaneously, the trap 218 is heated by a second heater, which is arranged to heat the trap material to vaporize the aerosol material collected on the trap 218. The vaporized aerosol material collected on the trap is thus carried by the reverse flow through the inlet 202 to the sampling port 222 for sampling by the spectrometer 302. Figure 2A As shown, the aerosols that reach the collector 218 for collection arrive at the side of the collector 218 closer to the sampling volume 224 and the sampling port 222. Therefore, when the collected aerosol material is vaporized by the second heater, the vaporized aerosols do not need to pass through the collector structure to reach the sampling port 222.

[0097] Figure 3 A schematic diagram of an inlet device 201 is shown, which includes more than one sampling port in the inlet. Inlet device 201 corresponds to... Figure 2A and Figure 2B The device differs in that instead of a single ion mobility spectrometer, it provides two ion mobility spectrometers, 302a and 302b. For example, spectrometers 302a and 302b can be configured to operate in different modes, specifically providing a positive-mode ion mobility spectrometer and a negative-mode spectrometer. Spectrometer 302a is configured to acquire samples through sampling port 222a, while spectrometer 302b is configured to acquire samples through sampling port 222b. It will be understood that, although Figure 3 It shows Figure 2A / Figure 2B The structure, but what will be understood is, Figure 3 The dual IMS configuration shown can also be used Figure 1A / Figure 1B The configuration shown. Figure 3 The aim is to demonstrate in general how to arrange inlet / detection devices that include more than one sampling port. Furthermore, although... Figure 3 The illustration shows spectrometers 302a and 302b spaced apart along the length of inlet 202, but in other embodiments, the spectrometers / sampling ports may be spaced apart around the diameter of inlet 202, such that sampling ports 302a / 302b are equidistant from the first heater 220 and the trap 218 (e.g., as shown). Figure 3 As shown above and below the entrance.

[0098] Figure 4 A method 400 is shown for operating a detection device to analyze vapor in real time while simultaneously collecting low-concentration aerosols on a trap. For example... Figure 4As shown, the method includes 402 providing the airflow to be tested to the inlet of the detection device. During a first time period, while operating in a first mode, steps 404, 406, and 408 are performed. In step 404, a first portion of the airflow is heated to vaporize aerosols in the airflow, and in step 406, the vaporized aerosols from the first portion are sampled by an analytical device for analysis. Also during the first time period, aerosols present in a second portion of the airflow are collected on a trap.

[0099] Finally, during the second time period, operating in the second mode, in step 410, the aerosol material captured on the trap is vaporized (e.g., by heating the trap), and the vaporized aerosol material from the trap is sampled by the analytical device for analysis.

[0100] What will be understood is that, although Figure 4 Only the operation under the first and second modes is shown, but the analytical apparatus can also be operated to sample vapor, regardless of whether the aerosol is being vaporized for analysis (e.g., via the first heater or trap). For example, where heating the airflow to vaporize the aerosol, as described elsewhere herein, is performed intermittently, the method may include sampling vapor from the test airflow for analysis during intervals when the test airflow is not heated for vaporization. For example, vapor may be sampled for analysis while the aerosol is collected on the trap in step 408, for example, if the test airflow has not been heated before sampling.

[0101] Although embodiments of this disclosure are described as having specific applications in ion mobility spectrometry, the described apparatus and methods can be applied to other analytical systems that require testing vapors, such as vapors associated with aerosols having low vapor pressures.

[0102] It will be understood that vapor can comprise the gaseous phase of a substance at a temperature below its critical point. In contrast to vapor or gas, aerosols comprise fine solid or liquid particles suspended in a gas. As used herein, the term "vaporization" is used to mean the conversion of at least some substance from a solid or liquid into vapor or gas.

[0103] Typically, the device features described in this paper can be provided as method features, and vice versa.

[0104] It should also be understood that specific 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 within the context of this disclosure.

Claims

1. An inlet device for a detection system, the device comprising: An inlet for receiving the airflow to be measured, the inlet including a first heater configured to vaporize air-borne aerosols for sampling by the analytical device; A trap, configured to collect aerosols from an air stream and vaporize the collected aerosols for sampling by the analytical device; The inlet device is configured to provide the airflow to be measured to: (i) The first heater, which vaporizes aerosols in the airflow for sampling by the analytical apparatus, and (ii) The trap is used to collect aerosols while an airflow is supplied to the first heater.

2. The inlet device according to claim 1, wherein, The entry point includes: A first flow path, the first flow path including a first heater and one or more sampling ports located downstream of the first heater, the analysis device being able to acquire a sample from the inlet through the one or more sampling ports; A second flow path, the second flow path including the trap; A first flow provider, the first flow provider being configured to cause a first portion of the airflow to flow along the first flow path from the first heater through the one or more sampling ports; and A second flow provider is used to cause a second portion of the airflow to flow through the trap along the second flow path.

3. The inlet device according to claim 2, wherein, The second flow path extends upstream of the first flow path from one or more sampling ports.

4. The inlet device according to claim 2 or 3, wherein, The second flow path is separated from the first flow path by the trap.

5. The inlet device according to claim 3 or 4, wherein, The trap is arranged such that when the second flow provider is turned off, or when the second flow provider provides a reverse flow from the trap into the first flow path, vaporized aerosols vaporized from the trap can enter the first flow path for sampling by the one or more sampling ports.

6. The inlet device according to any one of claims 2 to 5, wherein, The first flow path is defined by a first conduit configured to guide the first portion of the airflow through the first heater and then through the one or more sampling ports configured to provide a sample to the analytical device through the wall of the first conduit.

7. The inlet device according to claim 6, wherein, The second flow path is defined by a second conduit that branches off from the first conduit at a junction upstream of one or more sampling ports, and wherein the trap is disposed at the junction of the first and second conduits to collect aerosols present in the second portion of the airflow entering the second conduit, while allowing aerosols in the first portion of the airflow to pass along the first conduit.

8. The apparatus according to any one of claims 2 to 7, wherein, The inlet device is operable in a first mode and a second mode. In the first mode, the first heater is operated to vaporize the aerosol carried by the first portion of the airflow for sampling by the analytical device, and wherein the aerosol carried by the second portion of the airflow is collected on the trap. In the second mode, the aerosols collected on the trap are vaporized for sampling by the analytical device.

9. The inlet device according to claim 8, wherein, In the first mode, the first flow provider and the second flow provider can operate simultaneously to provide the first portion of the airflow along the first flow path and the second portion of the airflow along the second flow path.

10. The inlet device according to claim 9, wherein, The inlet device is capable of operating in the second mode such that when the second flow provider is closed or operated in reverse, the aerosol collected from the trap vaporization enters the first flow path and is provided by the first flow provider to the one or more sampling ports.

11. The inlet device according to claim 1, wherein, The inlet defines a flow path having a first end and a second end, the first end being configured to receive the airflow to be measured, and the inlet includes: One or more sampling ports, through which the analytical device can acquire a sample from the inlet, the one or more sampling ports being arranged between the first heater and the second end, such that aerosol flowing from the first end to the second end through the inlet can be vaporized by the first heater and provided to the one or more sampling ports; The trap is arranged between the one or more sampling ports and the second end, such that aerosols carried by the airflow that have passed through the first heater and the one or more sampling ports are collected on the trap.

12. The inlet device according to claim 11, wherein, The inlet includes a conduit configured to receive and guide the airflow to be measured along the flow path.

13. The inlet device according to claim 11 or 12, comprising a flow provider capable of operating in a first mode to provide a first flow from the first end to the second end through the inlet, and the flow provider capable of operating in a second mode to provide a second flow from the second end to the first end through the inlet.

14. The inlet device according to claim 13, wherein, In the first mode, the first heater is operable to provide intermittent heating so as to allow aerosols in the first portion to pass through the first heater unvaporized for collection on the trap.

15. The inlet device according to claim 13 or 14, wherein, In the second mode, the trap is operable to vaporize the collected aerosol carried by the second flow for sampling by the analytical device through the one or more sampling ports.

16. The inlet device according to any one of the preceding claims, wherein, The trap includes a second heater for vaporizing the collected aerosols.

17. The inlet device according to any one of the preceding claims, wherein, The trap comprises a fiberglass material, such as glass wool.

18. The inlet device according to any one of the preceding claims, wherein, The first heater includes conductors arranged across the inlet such that the airflow to be measured passes between the conductors, for example, wherein the first heater includes an array of elongated conductors or wires extending across the inlet, such as a grid or an array of parallel elongated conductors.

19. An inlet device for a detection system, the device comprising: An inlet for receiving the airflow to be measured, the inlet including a first heater configured to vaporize air-borne aerosols for sampling by the analytical device; as well as A trap, configured to collect aerosols from the airflow and vaporize the collected aerosols for sampling by the analytical device; The inlet device can operate in both a first mode and a second mode: In the first mode, the first heater is operated to vaporize the aerosol carried by the first portion of the airflow for sampling by the analytical device, and wherein the aerosol carried by the second portion of the airflow is collected on the trap. and In the second mode, the aerosols collected on the trap are vaporized for sampling by the analytical device.

20. The apparatus according to claim 19, wherein, The inlet device is further defined according to any one of claims 2 to 18.

21. A detection device comprising an inlet device as described in any of the preceding claims and an analysis device, the analysis device being configured to acquire a sample from the inlet for detecting a substance of interest, for example, wherein the analysis device comprises an ion mobility spectrometer.

22. A method of operating a detection device to analyze vapors and aerosols, the method comprising: During the first time period, the detection device is operated in the first mode to: The airflow to be measured is supplied to the inlet of the device; A first portion of the airflow is heated to vaporize the aerosols carried by the first portion of the airflow for sampling by the analysis device, while aerosols carried by a second portion of the airflow are also collected on a trap. as well as During the second time period, the detection device is operated in the second mode to: The aerosols collected by the trap are vaporized for sampling by the analytical device.

23. The method according to claim 22, wherein, In the first mode, the airflow to be tested is divided into a first part and a second part. The first part is guided along a first flow path through a first heater and then through one or more sampling ports. The analytical device acquires samples through the one or more sampling ports. The second part is guided to flow along a second flow path including the trap, which extends upstream of the one or more sampling ports from the first flow path.

24. The method according to claim 23, wherein, In the second mode, aerosols collected by the trap are vaporized and provided along the first flow path to the one or more sampling ports for sampling by the analytical device; for example, a reverse flow is provided from the second flow path through the trap into the first flow path, or the trap separates the first flow path from the second flow path, and aerosols vaporized from the trap enter the first flow path and are carried by the airflow along the first flow path to the one or more sampling ports.

25. The method according to claim 24, wherein, In the first mode, the first portion is provided by a first flow provider arranged in the first flow path, passing through the first heater and then through the one or more sampling ports, and the second portion is provided to the trap by a second flow provider arranged in the second flow path.

26. The method according to any one of claims 23 to 25, wherein, In the first mode, the analytical device is operated to sample and analyze aerosols vaporized by the first heater, while the aerosols are collected on the trap. In the second mode, the analytical device is operated to sample and analyze aerosols collected from the trap.

27. The method according to claim 22, wherein, In the first mode, the airflow to be tested is provided along a flow path, passes through a first heater for vaporizing aerosols in the airflow, then through one or more sampling ports through which the analytical device acquires samples for analysis, and then reaches a trap, for example, wherein the flow path is provided by a conduit having a wall configured to receive and guide the airflow along the flow path.

28. The method according to claim 27, wherein, In the first mode, the aerosol carried by the first portion of the airflow is vaporized by the first heater for sampling through the one or more sampling ports, wherein the first heater is operated intermittently during the first time period, and when the heater is turned off, the second portion of the airflow delivers the aerosol to the trap via the first heater.

29. The method according to claim 27 or 28, wherein, In the second mode, a reverse flow is provided along the flow path, through the trap, and then through the one or more sampling ports for sampling by the analysis device.

30. The method according to any one of claims 27 to 29, wherein, In the first mode, the operation of the analytical device is synchronized with the operation of the first heater to sample aerosols vaporized by the first heater through the one or more sampling ports, and in the second mode, the operation of the analytical device is synchronized with the vaporization of aerosols collected on the trap to sample aerosols vaporized from the trap through the one or more sampling ports.

31. The method according to any one of claims 22 to 30, wherein, The method includes alternating between operating in the first mode and then in the second mode multiple times.

32. The method according to any one of claims 22 to 31, wherein, In the first mode, the air stream to be tested is intermittently heated to vaporize the aerosol, and the analytical device is operated to acquire a sample from the air stream without heating the air stream to sample the vapor present in the air stream.

33. The detection apparatus of claim 21, further comprising a controller configured to control the detection apparatus to perform the method of any one of claims 22 to 32.

34. A computer program product configured to program a controller of a detection device to perform the method according to any one of claims 22 to 32, or a fixed logic circuit configured to control the detection device to perform the method according to any one of claims 22 to 32.

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