Sampling system, detection device and use method thereof

Abstract

A sampling system for a detection device comprising (i) an ion analyzer having an ionizer and (ii) an optical analyzer for detecting a substance of interest on a sample receiving surface. The sampling system comprises: a detector inlet for obtaining a volume of air to be sampled; an ion analyzer sampling inlet arranged at the detector inlet, obtaining a first sample from the volume of air at the detector inlet and providing the first sample to the ionizer; and a sample receiving surface disposed at the detector inlet to receive a second sample from the volume of air at the detector inlet for optical analysis thereof.

Description

Technical Field

[0001] The present disclosure relates to the field of detection devices and methods. For example, the present disclosure relates to a sampling system for a detection device, and a detection device including such a sampling system. The present disclosure also includes methods of operating such a sampling system and / or a detection device. Background Art

[0002] There are many different spectrometry-related techniques for identifying the presence of a substance of interest in a given sample. Implementations of these techniques can be used to detect the presence of chemical warfare agents ("CWA") or toxic industrial chemicals ("TIC") or any other chemical of interest (including, for example, explosives and their precursors). For such implementations, different sampling methods are typically implemented. In some cases, dedicated vapor sampling ("vapor sniffing mode") is implemented. In other cases, the sample is typically provided on some form of substrate. The substrate and sample are then heated to desorb the sample from the substrate in vapor form. The vapor is then passed to a detector, which measures the properties of the vapor and detects the presence of the substance of interest based on these measurements. For example, in an ion mobility spectrometer ("IMS") or a mass spectrometer ("MS"), ionized molecules can be identified based on their mobility in a carrier buffer gas or air or based on other properties. Detection devices that utilize these techniques to detect the presence of dangerous or illegal materials (such as CWAs and TICs) are known. Summary of the invention

[0003] Various aspects of the disclosure are set out in the independent claims, and optional features are set out in the dependent claims. Various aspects of the disclosure may be provided in combination with each other, and features of one aspect may be applied to other aspects.

[0004] In one aspect, a sampling system for a detection device is provided, the detection device comprising: (i) an ion analyzer having an ionizer, and (ii) an optical analyzer (e.g., a surface enhanced Raman spectroscopy (SERS) analyzer) for detecting a substance of interest on a sample receiving surface (e.g., a SERS active surface). The sampling system comprises: a detector inlet for obtaining a volume of air to be sampled; an ion analyzer sampling inlet, which is arranged in the detector inlet to obtain a first sample from the volume of air in the detector inlet and provide the first sample to the ionizer; and a sample receiving surface (e.g., a SERS active surface), which is arranged in the detector inlet to receive a second sample from the volume of air in the detector inlet for optical (e.g., SERS) analysis thereof.

[0005] Embodiments can achieve increased reliability for detecting substances of interest. For example, using an ion analyzer with an ionizer and an optical (e.g., SERS) analyzer to detect the presence of substances of interest can enable the presence or absence of potentially obscure substances to be confirmed or denied based on data from two analyzers. For example, a positive result from an ion analyzer can be confirmed or denied using an optical analyzer, or a positive result from an optical analyzer can be confirmed or denied using an ion analyzer. In other words, embodiments can enable optically active detection (e.g., SERS detection) to be performed in conjunction with ion analyzer detection (e.g., ion mobility spectroscopy or mass spectrometry). For example, this can enable orthogonal detection to be provided.

[0006] The optical analyzer may be a surface enhanced Raman spectroscopy (SERS) analyzer for detecting a substance of interest on a SERS active sample receiving surface. The sample receiving surface may be an optically active sample receiving surface for optical analysis thereof. The sample receiving surface of the sampling system may be a SERS active surface arranged to receive a second sample for SERS analysis thereof.

[0007] The sample receiving surface (e.g., SERS active surface) can be arranged downstream of the ion analyzer sampling inlet in the direction of air flow through the detector inlet. For example, the sampling system can include a blower configured to provide an air flow through the sampling system (e.g., from an upstream position toward a downstream position). The sample receiving surface (e.g., SERS active surface) can be arranged so that the air flow through the detector inlet hits the sample receiving surface (e.g., SERS active surface). The sample receiving surface (e.g., SERS active surface) can be arranged to span the direction of air flow through the detector inlet and / or it can be arranged parallel to the direction of air flow through the detector inlet. The surface can be gas permeable, or it can be a solid, gas impermeable surface. The system can be arranged so that air flowing through the detector inlet is forced through the sample receiving surface (e.g., SERS active surface) to deposit a second sample on the sample receiving surface (e.g., SERS active surface). The sample receiving surface (e.g., SERS active surface) can be arranged to hinder air from passing through the detector inlet. The sampling inlet can be disposed upstream of the sample receiving surface (e.g., SERS active surface) so that some of the air that has passed through (and not been drawn into) the sampling inlet will be directed to and blocked by the sample receiving surface (e.g., SERS active surface). In other examples, the sample receiving surface can be located in the same region as the ion analyzer sampling inlet or upstream of the ion analyzer sampling inlet.

[0008] The detector inlet may include a housing, such as a body, which defines a channel through which a gas sample can flow. The detector inlet may channel the gas sample to flow in a downstream direction. Some of the sample may be sucked in through the detector inlet. The remainder of the sample may travel further downstream (e.g., toward a sample receiving surface). A first portion of the gas sample (e.g., a first sample) may be sucked into the ion analyzer (e.g., toward the IMS) so that it may be analyzed by the ion analyzer. A second portion of the gas sample (e.g., a second sample) may contact a sample receiving surface (e.g., a SERS active surface) and be received thereon for optical (e.g., SERS) analysis thereof. In other words, the sampling inlet includes a portion of the detector inlet for sucking in some gas from the detector inlet so as to bring it to the ion analyzer. A sample receiving surface (e.g., a SERS active surface) is provided in the detector inlet for receiving a sample passing through the region (e.g., for optical analysis thereof). The first sample may be obtained before, simultaneously with, or after obtaining the second sample. The other of the first sample or the second sample may be analyzed only if analysis of one of the first sample and the second sample indicates that a substance of interest may be present. The sample may be a gas. The sample may include a vaporized aerosol (eg, an aerosol vapor).

[0009] A portion of the detector inlet may be arranged to enable optical (e.g., SERS) measurements to be obtained from a sample receiving surface (e.g., a SERS active surface). The portion of the detector inlet may be arranged to provide an optical path to the sample receiving surface to one or more light sources and / or one or more optical detectors. For example, the light source may include a Raman light source, and the optical detector may include a Raman detector. The Raman source and the detector may be arranged in a reflection mode, for example, the Raman detector is arranged to detect the associated light associated with the reflection from the SERS active surface. The portion of the detector inlet may include one or more holes in the detector inlet. The system may include a heater for heating the sample receiving surface (e.g., a SERS active surface). The heater may be operable to remove accumulated material from the surface. For example, the heater may be controlled to turn on and start heating to remove the sample that has been analyzed. Then, the heater may be controlled to turn off so that subsequent measurements can be made on the surface. The ion analyzer sampling inlet may include a pinhole inlet. The sampling system may be used for an ion analyzer including an ion mobility spectrometer IMS or a mass spectrometer MS. As described above, the optical analyzer may include a SERS analyzer. Additionally or alternatively, the system may include any suitable type of optical analyzer and / or any type of surface enhanced spectroscopic analysis method. Example optical analysis methods include the use of an infrared IR analyzer. An optical analyzer, such as an IR analyzer, may include an analyzer based on transmission (e.g., where light passes through the substrate) or reflection (e.g., where light reflects from the substrate). For example, a cross flow IR analyzer may be used.

[0010] In one aspect, a detection device for detecting substances of interest is provided, the device comprising: a sampling system as disclosed herein; an ion analyzer having an ionizer, wherein the ion analyzer is coupled to the sampling system and is arranged to identify the presence of one or more substances of interest in the first sample provided to the ion analyzer through an ion analyzer sampling inlet of the sampling system; and an optical analyzer (e.g., a SERS analyzer) coupled to the sampling system and is arranged to identify the presence of one or more substances of interest in the second sample received by the sample receiving surface (e.g., the SERS active surface) of the sampling system.

[0011] The ion analyzer may include an IMS or MS. The device may include a thermal desorber (e.g., a thermal desorber module) for generating a vapor sample that will be provided to the detector inlet as a sample. For example, the thermal desorber may be arranged upstream of the detection inlet to generate a gaseous sample to be provided to the detector inlet.

[0012] The device may be arranged so that the first sample and the second sample are provided by the same volume of air flowing through the detector inlet of the sampling system. The device may be configured to selectively control the operation of the two analyzers. For example, the device may be configured to first perform an analysis using one of the analyzers before subsequently performing an analysis with the other analyzer. The device may be configured so that one of the analyzers is used only when the other analyzer detects a substance of interest. For example, one of the analyzers may be used only as a confirmation analyzer, for example to confirm or deny a result obtained by the other analyzer.

[0013] The device may be configured to selectively control the operation of at least one of: (i) the operation of the optical (e.g., SERS) analyzer based on the operation of the ion analyzer, and / or (ii) the operation of the ion analyzer based on the optical (e.g., SERS) analyzer. The device may be configured to determine the presence of a substance of interest in the air from the detector inlet of a sampling system based on an analysis performed by both the ion analyzer and the optical (e.g., SERS) analyzer. The device may be configured to identify the presence of a substance of interest in the air from the detector inlet of a sampling system when both of the following occur: (i) the analysis performed by the ion analyzer indicates the presence of the substance of interest, and (ii) the analysis performed by the optical (e.g., SERS) analyzer indicates the presence of the substance of interest. The device may be configured to determine the absence of the substance of interest when at least one of the following occurs: (i) the analysis performed by the ion analyzer indicates the absence of the substance of interest, or (ii) the analysis performed by the optical (e.g., SERS) analyzer indicates the absence of the substance of interest. For example, the apparatus may be configured to determine that a substance of interest is not present if one of the analysers indicates that the substance is present, but the other analyser indicates that it is not present.

[0014] The device may be configured to control the operation of the ion analyzer to identify the presence of one or more substances of interest in the first sample, and in the case of identifying substances of interest in the first sample using the ion analyzer, the device may be configured to control the operation of the optical (e.g., SERS) analyzer to identify the presence of the substances of interest in the second sample. The device may be configured to control the operation of the optical (e.g., SERS) analyzer to identify the presence of one or more substances of interest in the second sample, and in the case of identifying substances of interest in the second sample using the optical (e.g., SERS) analyzer, the device may be configured to control the operation of the ion analyzer to identify the presence of the substances of interest in the first sample. The device may be configured to initially use only one active analyzer. The device may be configured to use the second analyzer only if the first analyzer indicates that substances of interest may be present. For example, the device may be configured to perform optical (e.g., SERS) analysis on second samples until one of the second samples contains substances of interest. In the case where the optical (e.g., SERS) analysis indicates the presence of substances of interest, the device may be configured to perform ion analysis (e.g., then use IMS or MS to analyze the sample).

[0015] The operation of the second analyzer can be controlled based on the results from the first analyzer. For example, in the case where the first analyzer indicates the presence of a first substance of interest, the second analyzer can be operated based on the first substance. For example, the analyzers can have different operating configurations, and a particular operating configuration can be selected based on the first substance to be identified. For example, a particular ion analyzer detection configuration (e.g., a detection algorithm) can be used based on the first substance detected by an optical (e.g., SERS) analyzer.

[0016] The apparatus may be configured to provide an output signal indicative of the detected material of interest. The output signal may include an indication of which analyzer indicated the material of interest was present, or an indication that both analyzers indicated the material of interest was present. For example, the output signal may provide a confidence score associated with how likely the output is to be correct based on whether only one or both of the analyzers found the material of interest to be present in the sample.

[0017] In one aspect, a method of controlling the operation of a sampling system for a detection device is provided, the detection device comprising: (i) an ion analyzer having an ionizer, and (ii) an optical analyzer (e.g., a surface enhanced Raman spectroscopy (SERS) analyzer) for detecting a substance of interest on a sample receiving surface (e.g., a SERS active surface). The method comprises: flowing air through a detector inlet of the sampling system; acquiring a first sample from the detector inlet and providing the first sample to an ionizer of the ion analyzer; and receiving a second sample from the detector inlet on a sample receiving surface (e.g., a SERS active surface) in the detector inlet.

[0018] In one aspect, a method is provided for controlling the operation of a detection device to identify the presence of one or more substances of interest in a volume of air flowing through a detector inlet of a sampling system of the detection device, the method comprising at least one of the following: (i) operating an ion analyzer to identify the presence of one or more substances of interest in a first sample obtained from the detector inlet, and, if the ion analyzer identifies the presence of one or more substances of interest in the first sample, operating an optical (e.g., surface enhanced Raman spectroscopy (SERS)) analyzer to identify the presence of the one or more substances of interest in a second sample received on a sample receiving surface (e.g., a SERS active surface) in the detector inlet, and (ii) operating an optical (e.g., SERS) analyzer to identify the presence of one or more substances of interest in a second sample received on a sample receiving surface (e.g., a SERS active surface) in the detector inlet, and, if the optical analyzer identifies the presence of one or more substances of interest in the second sample, operating the ion analyzer to identify the presence of the one or more substances of interest in the first sample obtained from the detector inlet.

[0019] In one aspect, a method for detecting the presence of a substance of interest in a volume of air flowing through a detector inlet of a sampling system is provided, the method comprising: determining whether a first substance of interest is present in a first sample obtained from the detector inlet based on ion analyzer data from an ion analysis of the first sample; determining whether the first substance of interest is present in a second sample received on a sample receiving surface (e.g., a SERS active surface) in the detector inlet based on optical analyzer data from an optical (e.g., SERS) analysis of the second sample; and indicating the presence of the first substance of interest if it is determined that the first substance of interest is present in both the ion analyzer data and the optical (e.g., SERS) analyzer data.

[0020] Aspects of the present disclosure provide one or more computer program products comprising computer program instructions configured to program a controller to control the operation of an apparatus to perform any of the methods disclosed herein. For example, the computer program instructions may be configured to control the operation of a detection device to perform sample analysis using an ion analyzer such as an IMS or MS and an optical analyzer such as a SERS analyzer or an IR analyzer, as disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Some examples of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0022] Figure 1 is a schematic diagram of the sampling system.

[0023] Figure 2 is a schematic diagram of the detector.

[0024] In the drawings, the same reference numerals are used to denote the same elements. DETAILED DESCRIPTION

[0025] The present disclosure relates to systems and methods that can utilize optical analysis, such as surface enhanced Raman spectroscopy ("SERS"), in combination with additional detection techniques. To this end, a sample to be analyzed can be separated so that a portion of the sample is analyzed using a SERS analyzer, while another portion of the sample is analyzed using a different analytical technique, such as using an ion mobility spectrometer ("IMS"). Two different detection methods can be used in combination to increase the detection reliability of the sample. The present disclosure includes a sampling system for providing separate detection flows: (i) one for SERS detection, and (ii) one for different (e.g., IMS) detection. The sampling system can receive a sample through a detector inlet, and the sample can flow through the sampling system. A portion of the sample can flow through an ion analyzer sampling inlet in the sampling system to a detector, where the portion of the sample will be analyzed. Another portion of the sample can flow onto a SERS active surface, where a SERS analysis can be performed on the portion of the sample. The SERS active surface can obstruct the flow path through a sampling inlet (eg, downstream of an ion analyzer sampling inlet) such that at least some sample that does not flow to the detector must pass through the SERS surface, resulting in some sample being deposited on the SERS surface.

[0026] Now refer to Figure 1 Describe an example of a sampling system.

[0027] Figure 1A sampling system 10 is shown, comprising a detector inlet for obtaining a volume of air to be sampled. The sampling system 10 is formed by a body 12. The sampling system 10 also comprises a sampling inlet 14 and a receiving surface for receiving a sample to be optically analyzed. Figure 1 In the example of FIG. 1 , the sample receiving surface is a surface enhanced Raman spectroscopy (“SERS”) active surface 18 (i.e., a SERS active surface to be SERS analyzed). A detector 100 is shown connected to the sample inlet 14. An optional heater 19 is also provided. Figure 1 The line through the body 12 shows the direction of flow of the volume of air to be sampled.

[0028] The sampling system 10 may also include a plurality of optical apertures 16. One or more light sources 28 are shown, as well as one or more light detectors 38. Figure 1 , the light source 28 and the detector 38 are shown as the same components. For example, each "source 28 - detector 38" pair can be arranged in a reflective configuration (where the detector 38 is used to detect reflected emissions of light). Sinusoidal lines illustrate photons of light (to help illustrate the light path between the light source 28 and the light detector 38). The detector 100 and the light source 28 and the light detector 38 are shown in dashed lines because they can be provided by components separate from the components of the sampling system 10.

[0029] The body 12 of the sampling system 10 provides a housing through which the gas will flow. The body 12 defines a passage through which the gas flows through the sampling system 10. The sampling system 10 may include a blower, such as a pump or a fan. The blower may control the movement of air through the sampling system 10. The blower may be operated to move air through the body 12 (e.g., Figure 1 ).

[0030] The sampling inlet 14 is provided in the body 12. For example, the sampling inlet 14 may include a pinhole inlet. The pinhole inlet may be provided in the body 12. The sampling inlet 14 may optionally include a membrane (for selectively controlling the air flow toward the detector 100). The detector 100 is connected to the sampling inlet 14.

[0031] The SERS surface 18 is provided in the body 12 (in a channel defined by the body 12 through which the gas flows). Figure 1 As shown, the SERS surface 18 is located downstream of the sampling inlet 14. In other examples, the SERS surface 18 can be located upstream of or above the sampling inlet 14. In each example, the SERS analysis is provided in parallel with the ion analyzer (e.g., so that different portions of the same sample are analyzed in different ways). For example, the SERS analysis can be performed as a pre-filter to perform the ion analyzer analysis. Figure 1As shown by the arrows in , the gas will flow through the body 12 (from left to right). For example, a blower of the sampling system 10 can be positioned to provide such a controlled gas flow through the body.

[0032] The sampling system 10 is arranged to divert some of the gas flowing through the body 12 toward the detector 100. For example, the detector 100 may include a suction element configured to draw air from a passage within the body 12 toward the detector through the sampling inlet 14. The sampling inlet 14 may include a pinhole inlet and / or a membrane covering, for example, to inhibit unintended flow of gas through the sampling inlet 14. In other words, the sampling system 10 may be configured to selectively and actively draw gas through the sampling inlet 14 (e.g., when the gas is to be sampled by the detector 100).

[0033] Gas moving through the passages of body 12 that is not drawn into sampling inlet 14 will continue to flow downstream of the sampling inlet (eg, as controlled by a blower). Sampling system 10 is arranged so that some of the air flowing downstream of sampling inlet 14 will be provided to SERS surface 18 .

[0034] The channel of the body 12 can provide a detector inlet. The channel of the body 12 (e.g., the detector inlet) can be arranged to receive a sample to be analyzed. The sample can include a gas, such as a gas that has been desorbed from a swab (or any other suitable such sample collection device). In addition or alternatively, the sample can include an aerosol (e.g., an evaporated aerosol). For example, the device of the present disclosure can be configured to convert the aerosol into a vapor (e.g., using a heater), for example, where the vapor can be provided as a sample to be analyzed. The sampling system 10 is arranged so that some of the air flowing through the channel of the body 12 (e.g., as provided from the sample to be analyzed) will be delivered to the detector 100 (through the sampling inlet 14), and some of the air flowing through the channel of the body will be delivered to the SERS surface 18. An air mover can be arranged to control the flow of air, wherein the air is received from the sample (e.g., from a thermal desorption module) to the detector inlet, and then through the channel of the body 12 toward the analyzer. The sampling system is operable to draw some air through the sampling inlet 14 (eg, by providing suction in that area) and deliver some air to the SERS surface (eg, as the air continues to flow through the channels of the body 12, past the sampling inlet 14).

[0035] The SERS surface 18 may be arranged to span the channel of the body 12 (e.g. Figure 112 ). The SERS surface 18 can extend across a majority of the width of the channel. For example, the SERS surface 18 can obstruct a majority of the cross-section of the channel. The SERS surface 18 can extend across the channel to obstruct the flow of gas through the channel. For example, the SERS surface 18 can be substantially perpendicular (e.g., perpendicular) to the direction of flow through the channel (e.g., perpendicular to the longitudinal axis of the body 12). The SERS surface 18 can be at least partially gas permeable, or the surface 18 can be provided by a solid (e.g., impermeable) substrate.

[0036] However, it should be understood that the SERS surface 18 can be provided in an additional or alternative configuration. For example, the SERS surface 18 can be parallel to the direction of air flow through the channel. The SERS surface 18 can be arranged so that when air containing sample material moves through the channel, at least some sample material can be provided on the SERS surface 18.

[0037] The heater 19 may be located near the SERS surface 18. It should be understood that any suitable heater may be provided, such as a resistive heater (e.g. Figure 1 The SERS surface 18 may be electrically connected to the SERS surface 18, for example, they may be electrically connected to at least a portion of the SERS surface 18.

[0038] The optical apertures 16 may include optically transparent regions of the body 12. For example, the optical apertures 16 may be holes in the body 12 (e.g., regions where no material is present), or they may be regions of optically transparent material in the body 12. The optical apertures 16 may be located near the SERS surface 18. The optical apertures 16 may be located both upstream and downstream of the SERS surface 18, or they may be located only on one side of the SERS surface 18 (e.g., Figure 1 ). The sampling system 10 may have an optical aperture 16 for one or more (eg, multiple) light sources 28. The sampling system 10 may have an optical aperture 16 for one or more (eg, multiple) light detectors 38.

[0039] exist Figure 1In the example shown, the optical aperture 16 (both the light source 28 and the detector 38) is located upstream of the SERS surface 18. However, it should be understood that this is not intended to be limiting. The light source 28 and / or the detector 38 can be provided on either or both sides of the SERS surface 18. For example, both the light source 28 and the light detector 38 can be provided on the same side of the SERS surface 18. The light source 28 and the detector 38 are arranged to be disposed close enough to the SERS surface 18 so that they can be used to perform SERS analysis on samples on the surface 18.

[0040] exist Figure 1 In the example of , the sample receiving surface is a SERS surface 18. However, it should be understood that other forms of optical analysis can be used. For example, an infrared analyzer can be provided for optically analyzing the sample receiving surface. For the SERS surface 18, the light source 28 and the detector 38 can be provided in a reflective arrangement (e.g., for the detector 38 to detect reflected light from the light source 28). For an infrared surface, the light source 28 and the detector 38 can be provided in a transmissive arrangement (e.g., the detector 38 is located on the side of the surface opposite to the light source 28).

[0041] The sampling system 10 is arranged to receive a gaseous substance to be sampled. Although not shown, a gas sample receiving area may be located at Figure 1 10 upstream of the portion of the sampling system 10 shown in . That is, the sampling system 10 may include an intake region in which a gas sample is drawn into the sampling system 10, such as from a swab. The sampling system 10 is arranged to provide a flow through configuration. The sampling system 10 is arranged to provide a gas sample as an input to the sampling system 10 and flow through the sampling system 10. The blower may be arranged to operate to provide such a sample flow through the channel of the body 12. For example, the blower is configured to guide the gas sample from an upstream position (e.g., where the gas sample is received, such as from a swab) to downstream. The blower is configured to control the gas sample to flow downstream toward the sampling inlet 14 (and also toward the SERS surface 18). The sampling system 10 and / or the detector 100 may be arranged to extract at least some of the received gas samples toward the detector 100 through the sampling inlet 14. The blower is configured to flow the sample through the channel so that at least some of the received gas samples will be provided on the SERS surface 18 within the channel.

[0042] The sampling system 10 may be arranged to provide analyte neutrals from the same sample to both the detector 100 (through the sampling inlet 14) and the SERS surface 18. The sampling system 10 is arranged to provide: (i) a first portion of the gas sample (through the sampling inlet 14) to the detector 100, and (ii) a second portion of the same gas sample to the SERS surface 18. The sampling system 10 is arranged to facilitate parallel detection using the detector 100 (e.g., an IMS) and a SERS analyzer (which analyzes the sample provided on the SERS surface 18). In other words, the sampling system 10 is arranged to redistribute some portions of the same sample into one of two different regions where they can be analyzed. The sampling system 10 is arranged with the sampling inlet 14 upstream of the SERS surface 18. The detector 100 (or a blower of the sampling system 10) may be arranged to draw a portion of the sample to be analyzed by the detector 100 from a flow path through the channel of the body 12 toward the detector 100 (through the sampling inlet 14). The sampling system 10 is configured to provide some of the remaining portion of the sample (which is to be SERS analyzed) to the SERS surface 18 .

[0043] The body 12 may be arranged to define a fluid flow path for a gas sample. The body 12 may be arranged to restrict a gas flow through a channel of the body 12 from upstream to downstream. An upstream portion of the body 12 may be arranged to receive a gas sample. The body 12 may be configured to direct the gas sample to the SERS surface 18. The sampling inlet 14 may be arranged upstream of the SERS surface 18 in the body 12. The sampling inlet 14 may be arranged to receive a portion of the gas flowing through the channel in the body 12 (e.g., a portion of the gas flowing through the channel in the body 12 may be actively drawn in through the sampling inlet 14, such as through a pinhole inlet). The sampling system 10 is configured to operate so that a portion of the gas flowing through the channel toward the SERS surface 18 is instead diverted through the sampling inlet 14 (towards the detector 100). The body 12 is arranged so that the remainder of the gas will flow toward the SERS surface 18, some of which will be provided onto the SERS surface 18 (and some will flow outside the SERS surface 18, such as toward the outlet of the sampling system 10).

[0044] The detector 100 is configured to detect the presence of one or more substances of interest in a portion of a sample provided to the detector 100. The detector 100 includes an ion analyzer having an ionizer. The ionizer is arranged to ionize a portion of the sample provided to the detector 100. The ion analyzer is arranged to analyze those ions to detect the presence of substances of interest in the sample. The detector 100 can be any suitable detector, such as a mass spectrometer, or an ion mobility spectrometer ("IMS"). The detector 100 can be arranged to detect the presence of substances of interest based on one or more properties of the sample, such as the mobility or mass of the sample and / or ions ionized from the sample. The detector 100 can be arranged to receive analyte neutrals through the sampling inlet 14. The detector 100 can be arranged to ionize those analyte neutrals and perform detection on the ionized sample. In contrast, the sample deposited on the SERS surface 18 can be analyte neutral particles (e.g., which have not yet been ionized by the ionizer). The following will be combined with Figure 2 The illustrated IMS describes one example of detector 100 in more detail.

[0045] The SERS surface 18 may be arranged to hinder the flow of gas through the channel from an upstream position toward a downstream position. For example, the SERS surface 18 may be arranged in the channel so that at least some of the gas sample flowing in the channel downstream of the sampling inlet 14 will be deposited on the SERS surface 18. The sampling system 10 may be arranged to force (most of) the gas sample to attempt to flow through the SERS surface 18. The SERS surface 18 may be arranged so that some gas may flow through it, but some gas will not flow through it, resulting in a portion of the sample being provided on the SERS surface 18 (where it can be SERS analyzed).

[0046] The (one or more) light sources 28, (one or more) light detectors 38 and the SERS surface 18 may form a SERS analyzer. The SERS analyzer may be arranged to perform SERS analysis on any substance on the SERS surface 18. The SERS analyzer may include one or more light sources 28 arranged to direct light toward the SERS surface 18. Each light source 28 may be located near the optical aperture 16 of the body 12, and the line of sight is at the SERS surface 18 in the channel. The light source 28 may include a laser. Each light detector 38 may be located near the optical aperture 16 of the body 12, and the line of sight is at the SERS surface 18 in the channel. The light detector 38 may be arranged to detect scattered light from a sample on the SERS surface 18. The SERS analyzer may be configured to determine one or more properties of the sample based on the wavelength of the scattered light received by the light detector 28. The SERS analyzer may be arranged to determine whether a substance of interest is present in the sample based on the Raman scattered light of the sample (e.g., based on the wavelength of the Raman scattered light). The SERS analyzer can be arranged downstream of the sampling inlet 14 in the sampling system 10 so that the portion of the sample to be (ionized and) analyzed by the detector 100 is different from the portion of the same sample to be analyzed by the SERS analyzer. The detector 100 can be arranged to analyze analyte ions, and the SERS analyzer can be arranged to analyze analyte neutral particles.

[0047] The heater 19 may be selectively operable to heat the SERS surface 18. The heater 19 may include a resistive heater 19 arranged to generate heat in response to a voltage applied to the heater 19. The heater 19 may be arranged to heat the SERS surface 18 to drive off accumulated material on the SERS surface 18 (e.g., a sample that has been previously deposited on the surface). The heater 19 may be controlled to heat the SERS surface 18 before performing a subsequent SERS analysis (e.g., after the SERS analyzer has completed performing a previous SERS analysis on a sample on the SERS surface 18).

[0048] although Figure 1 10 . Although not shown, the sampling system 10 may be provided in conjunction with a flow control system. The flow control system may include one or more blowers, such as pumps or fans (as described above). The flow control system may be arranged to provide the fluid flow dynamics described above for the sampling system 10 (e.g., so that the gas sample flows downstream through the sampling system 10). The sampling system 10 may include a flow control system, for example, the sampling system 10 may include one or more blowers that are arranged to control the flow of air through the body 12 (e.g., the sampling system 10 may include one or more pumps). Additionally or alternatively, the flow control system may be provided by an external device, such as a device located upstream and / or downstream of the sampling system 10, or the flow control system may be provided as part of the detector 100.

[0049] Embodiments of the present invention may provide a detection device comprising a detector 100, a sampling system 10, and a SERS analyzer as described above. Such a detection device may also include a controller configured to control the operation of the detection device. The controller may be coupled to the detector 100 to control its operation, and / or receive from it a signal indicating the presence of any substance of interest in a sample analyzed by the detector 100. The controller may be coupled to the SERS analyzer to control its operation, and / or receive from it a signal indicating the presence of any substance of interest in a sample analyzed by the SERS analyzer. The controller may be coupled to a flow control system to selectively control the flow of gas through the sampling system 10.

[0050] The controller is configured to determine whether a material of interest is present in a sample based on: (i) an analysis performed by the detector 100 on a first portion of the sample (e.g., containing analyte ions), and (ii) a SERS analysis performed by the SERS analyzer on a second portion of the same sample (e.g., containing analyte neutrals). The controller can be configured to confirm or deny an analysis performed by one of the analyzers using the other analyzer. For example, a SERS analysis can be used to confirm / deny an IMS analysis, and vice versa. In one example, if a SERS analysis indicates that a material of interest is present in a sample, the use of the IMS can be limited by only using the IMS to analyze the sample.

[0051] The controller may be arranged to confirm the presence of a substance of interest in a sample when both the analysis from the detector 100 and the analysis from the SERS analyzer indicate the presence of the substance of interest in the sample. The controller may reduce the false alarm rate of the detector 100, for example, the controller may be configured to indicate that the substance of interest is present in the sample only when both the detector 100 and the SERS analyzer indicate the presence of the substance of interest. For example, in the case where two different substances have similar ion mobilities, the detector 100 may not be able to distinguish which of the two different substances is present. However, the use of a SERS analyzer may enable such a determination to be performed (and likewise the IMS is able to distinguish between two different substances that a SERS analyzer may not be able to distinguish).

[0052] The controller can be configured to determine that the material of interest is not present if the detector 100 indicates that the material of interest is present in the sample, but the SERS analyzer indicates that the material of interest is not present (or vice versa). The controller can be configured to determine that the material of interest is present in the sample if both the detector 100 and the SERS analyzer indicate that the material of interest is present.

[0053] The controller can be configured to selectively use one of the analyzers based on an output from another analyzer. For example, the controller can be configured to use the SERS analyzer only when the detector 100 indicates that a substance of interest has been identified in the sample (e.g., when the detector 100 has identified one or more substances in the sample that have properties similar to the properties of the substance of interest (e.g., ion mobility or mass properties)), or vice versa (e.g., use the IMS only when the SERS analyzer indicates that a material of interest is present). For example, in the case where the controller obtains an indication that the detector 100 has identified such a substance of interest in the sample, the controller can control the operation of the SERS analyzer to perform a SERS analysis on the substance received by the SERS surface 18 in the sampling system 10. The controller can determine whether the substance of interest is present based on a subsequent SERS analysis performed on the sample. This approach can reduce the number of times the SERS analyzer needs to be used. For example, the SERS analyzer is used only when the detector 100 indicates that a substance of interest may be present in the sample. An alternative ordering can also be provided, that is, when the SERS analyzer indicates that a substance of interest is present, the number of times the IMS is used is reduced by using only the IMS.

[0054] The controller may be configured to control the operation of a flow control system (e.g., one or more blowers) and / or a heater 19. The controller may be configured to control the flow control system to operate such that a gas sample flows through the sampling system 10, wherein a portion of the sample is drawn into the detector 100 through the sampling inlet 14, and a portion of the sample is provided on the SERS surface 18. The controller may be configured to control the operation of the flow control system such that no new sample is delivered through the sampling system 10 until after it has been determined whether a substance of interest is present in the original sample. For example, the controller may control the flow control system to stop driving the sample to flow through the sampling system 10 until it has been determined whether a substance of interest is present. Once the controller determines whether a substance of interest is present in the sample (e.g., after the results of the detector 100 and the results of the SERS analyzer, if desired), the controller may control the operation of the heater 19 to heat the SERS surface 18 and desorb any material from the SERS surface 18 (e.g., it may be driven downstream of the SERS surface 18). The controller may then control the flow control system to provide a new sample to the sampling system 10 for analysis by the detector 100 and possibly the SERS analyzer.

[0055] In operation, a gas sample flow is provided through a channel in the body 12 of the sampling system 10. A first portion of the gas sample will be drawn into the detector 100 through the sampling inlet 14. The detector 100 will ionize and ion analyze the first portion of the sample. A second portion of the same gas sample will be provided on the SERS surface 18 in the channel downstream of the sampling inlet 14. If the analysis of the first portion of the sample indicates that a substance of interest may be present in the sample, a SERS analysis is performed on the material deposited on the SERS surface 18. If the SERS analysis indicates that the substance of interest is not present in the sample, a false alarm is output, indicating that the output from the detector 100 is a false positive (e.g., there is another substance with similar properties to the substance of interest in the sample, but it is not the substance of interest). If the SERS analysis indicates that a substance of interest is present in the sample, and it is the same substance as the substance indicated by the detector 100, an alarm is output to indicate that the substance of interest is present in the sample. A heater 19 can be used to heat the SERS surface 18 to remove any sample thereon (e.g., each time a new surface is provided to the SERS surface 18).

[0056] However, in the context of the present disclosure, it should be understood that such sequential sorting need not be performed. For example, detection data for each sample may be obtained from both the SERS analyzer and the detector 100. The controller may determine whether a substance of interest is present based on the two data streams for each sample.

[0057] As will be appreciated in the context of the present disclosure, the detector 100 may be provided by a variety of different forms of detectors. Examples include any suitable spectrometer, such as a mass spectrometer or IMS, to name a few. Reference will now be made to Figure 2 , which shows an example of a detector that can be used as described above.

[0058] Figure 2 is an illustration of a partial cross section through a detector in the form of an ion mobility spectrometer (“IMS”) 280 .

[0059] Figure 2 The ion mobility spectrometer 280 shown in FIG. 1 includes an ionizer 288 separated from a drift chamber 292 by a door 282. The door 282 can control the passage of ions from the ionizer 288 to the drift chamber 292. As shown, the IMS 280 includes an inlet 281 for enabling material to be introduced from a sample of interest to the ionizer 288 (e.g., via an inlet channel opening).

[0060] exist Figure 2In the example shown, the drift chamber 292 is located between the ionizer 288 and the detector 287, so that ions can reach the detector 287 by passing through the drift chamber 292. The drift chamber 292 can include a series of drift electrodes 283, 284 for applying a voltage distribution along the drift chamber 292 to move ions from the ionizer 288 along the drift chamber 292 toward the detector 287.

[0061] The IMS 280 can be configured to provide a drift gas flow in a direction generally opposite to the path of travel of the ions to the detector 287. For example, the drift gas can flow from near the detector 287 to the door 282. As shown, a drift gas inlet 289 and a drift gas outlet 290 can be used to pass the drift gas through the drift chamber. Example drift gases include, but are not limited to, nitrogen, helium, air, recycled air (e.g., clean and / or dry air), etc.

[0062] The detector 287 can be coupled to provide a signal to a detection controller 294. The current from the detector 287 can be used by the controller 294 to infer that the ion has reached the detector 287, and the characteristics of the ion can be determined based on the time it took for the ion to reach the detector 287 from the gate 282 along the drift chamber 292. Examples of the detector 287 are configured to provide a signal indicating that the ion has reached the detector 287. For example, the detector can include a conductive electrode (e.g., a Faraday plate).

[0063] The electrodes 283, 284 may be arranged to direct ions toward the detector 287, for example, the drift electrodes 283, 284 may include a ring that may be arranged around the drift chamber 292 to focus the ions onto the detector 287. Figure 2 The example includes only two drift electrodes 283, 284, but in some examples, multiple electrodes may be used, or a single electrode may be used in combination with detector 287 to apply an electric field to guide ions to detector 287.

[0064] The spectrometer 280 is shown as including ion modification electrodes 285, 286 arranged in the drift chamber, but it will be appreciated in the context of the present disclosure that these may not be included.

[0065] like Figure 2 As shown, the voltage provider 293 is coupled to be controlled by the controller 294. The voltage provider 293 can also be coupled to provide a voltage to the ionizer 288 to enable material from the sample to be ionized. In an embodiment, the voltage provider 293 is coupled to the gate electrode 282 to control the passage of ions from the ionization chamber into the drift chamber 292. The voltage provider 293 can be coupled to the drift electrodes 283, 284 for providing a voltage distribution for moving ions from the ionizer 288 toward the detector 287.

[0066] As described above, the drift electrodes 283, 284 can provide a voltage profile that moves ions along the drift chamber, such that the ions travel from the ionizer to the detector. Figure 2 As shown, the first ion modifier electrode 285 and the second ion modifier electrode 286 may be spaced apart in the direction of ion travel.

[0067] The spectrometer and voltage provider may be contained in a common housing. In spectrometry, ion counts may be measured by peaks on the spectrum, and the height of the peak may be an indicator of the number of ions that arrive at the detector at a particular time. Ions produced by reactions of neutral molecules of a substance of interest may be referred to as "daughter ions," and ions that produce daughter ions may be referred to as "parent ions."

[0068] As mentioned above, other types of detectors can be used. For example, a mass spectrometer, such as a time-of-flight mass spectrometer, can be used. In such a spectrometer, the mass-to-charge ratio of the ions can be inferred from their flight time through the vacuum. In other types of mass spectrometers, ions can be separated based on their mass-to-charge ratio in other ways, such as by deflection under an electric or magnetic field.

[0069] The detection apparatus including the detector, the sampling system 10 and the SERS analyzer may be provided in a portable unit.

[0070] As disclosed herein, the detection device of the present disclosure can use a SERS analyzer to perform SERS analysis on a SERS surface. Such a SERS analyzer can be configured to provide excitation radiation in a typical band for Raman, such as near infrared (e.g., 850nm or 780nm), visible light (e.g., 635nm or 532nm), and / or possible UV (e.g., 250nm) to the active surface of the SERS surface. The SERS analyzer can be configured to collect radiation scattered by the SERS surface and analyze the scattered radiation to provide spectral data corresponding to the Raman signature of a sample (e.g., a sample provided on the SERS surface). The spectral data can be provided to a controller, which can store and / or process the data or provide the data for communication with another device.

[0071] Surface enhanced Raman spectroscopy or surface enhanced Raman scattering (SERS) is a surface sensitive technique that enhances Raman scattering by molecules adsorbed on a surface appropriately modified with nanostructures, such as plasmonic nanoparticles. For example, one method for performing SERS measurements is by depositing a sample onto a silicon or glass surface with nanostructured noble metal inclusions. The surface is typically prepared using a distribution of metal nanoparticles on the surface. The most commonly used visible light SERS metals are silver and gold. Aluminum has also been proposed for UV SERS. To reduce costs, SERS active particles can be provided on a substrate, for example nanoparticles can be provided on a substrate so that SERS can be performed on a sample on the substrate.

[0072] The SERS surfaces of the present disclosure can be modified with gold nanoparticles, possibly in a regular arrangement. The SERS surface can be selected to have reduced background fluorescence or no background fluorescence at a wavelength selected for SERS analysis (e.g., 850nm, 780nm, 633nm, 532nm, or 400nm). Example SERS surfaces include paper-based and / or other cellulose-based substrates modified with gold or silver nanoparticles. Other examples include membrane-based substrates (e.g., substrates commonly used in gas filters, such as PTFE and / or micron / nano porous glass, etc.) modified with gold or silver nanoparticles. Other examples also include (all of which can be modified with gold or silver nanoparticles): cloth-based substrates, such as carbon cloth, graphene or graphite sheets, and / or silicone or semiconductor structures.

[0073] It should be understood from the above discussion that the examples shown in the figures are exemplary only and include features that can be generalized, removed or replaced as described herein and as set forth in the claims. With reference to the drawings in general, it should be understood that the schematic functional block diagrams are used to indicate the functions of the systems and devices described herein. In addition, processing functions may also be provided by devices supported by electronic devices. However, it should be understood that the functions do not need to be divided in this manner and should not be considered to imply any specific hardware structure other than the hardware described and claimed below. The functions of one or more elements shown in the drawings may be further subdivided and / or distributed throughout the device of the present disclosure. In some examples, the functions of one or more elements shown in the drawings may be integrated into a single functional unit.

[0074] As those skilled in the art will appreciate in the context of the present disclosure, each example described herein can be implemented in a variety of different ways. Any feature of any aspect of the present disclosure can be combined with any other aspect of the present disclosure. For example, the method aspect can be combined with the device aspect, and the features of the operational description of the specific elements of the reference device can be provided in the method without using those specific types of devices. In addition, each feature of each embodiment is intended to be separable from the features described in conjunction with it, unless some other features are explicitly stated to be necessary for its operation. Of course, each of these separable features can be combined with any other feature in the examples in which these features are described, or combined with any other feature or combination of features in any other example described herein. In addition, without departing from the present invention, equivalents and modifications not described above can also be adopted.

[0075] Certain features of the methods described herein can be implemented in hardware, and one or more functions of the device can be implemented in method steps. It should also be understood in the context of the present disclosure that the methods described herein do not need to be performed in the order in which they are described, nor in the order in which they are depicted in the accompanying drawings. Therefore, the aspects of the present disclosure described with reference to products or devices are also intended to be implemented as methods, and vice versa. The methods described herein can be implemented in a computer program, or in hardware, or in any combination thereof. Computer programs include software, middleware, firmware, and any combination thereof. Such programs can be provided as signals or network messages, and can be recorded on computer-readable media, such as tangible computer-readable media that can store computer programs in non-transitory form. Hardware includes computers, handheld devices, programmable processors, general-purpose processors, application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and logic gate arrays.

[0076] For example, any controller (and any activities and devices outlined herein) may be implemented with fixed logic, such as an assembly of logic gates, or programmable logic, such as software and / or computer program instructions executed by a processor. The controller may include a central processing unit (CPU) and associated memory, which is connected to a graphics processing unit (GPU) and its associated memory. Other types of programmable logic include a programmable processor, programmable digital logic (e.g., a field programmable gate array (FPGA), a tensor processing unit (TPU), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), an application specific integrated circuit (ASIC), or any other type of digital logic, software, code, electronic instructions, flash memory, an optical disk, a CD-ROM, a DVD ROM, a magnetic or optical card, other types of machine-readable media suitable for storing electronic instructions, or any suitable combination thereof. Such data storage media may also provide data storage for the controller (and any devices outlined herein).

[0077] Other examples and variations of the present disclosure will be apparent to those skilled in the art in light of the context of the present disclosure.

Claims

1. A sampling system for a detection device, the detection device comprising: (i) an ion analyzer having an ionizer, and (ii) an optical analyzer for detecting a substance of interest on a sample receiving surface, the sampling system comprising: a detector inlet for obtaining a volume of air to be sampled; an ion analyzer sampling inlet disposed in the detector inlet to obtain a first sample from the volume of air in the detector inlet and to provide the first sample to the ionizer; and A sample receiving surface is disposed in the detector inlet to receive a second sample from the volume of air in the detector inlet for optical analysis thereof.

2. The sampling system of claim 1, wherein the optical analyzer is a surface enhanced Raman spectroscopy (SERS) analyzer for detecting substances of interest on a surface active sample receiving surface; and in, The sample receiving surface of the sampling system is a SERS active surface arranged to receive the second sample for SERS analysis thereof.

3. A sampling system according to any preceding claim, wherein the sample receiving surface is arranged downstream of the ion analyser sampling inlet in the direction of air flow through the detector inlet.

4. A sampling system according to any preceding claim, wherein the sample receiving surface is arranged such that the air flow through the detector inlet impinges on the sample receiving surface, optionally thereby depositing the second sample on the sample receiving surface.

5. The sampling system of claim 4, wherein the sample receiving surface is arranged transverse to the direction of air flow through the detector inlet.

6. A sampling system according to claim 4 or 5, wherein the system is arranged such that air flowing through the detector inlet is forced across the sample receiving surface to deposit the second sample on the sample receiving surface.

7. A sampling system according to any preceding claim, wherein a portion of the detector inlet is arranged to enable optical measurements to be obtained from the sample receiving surface.

8. A sampling system according to claim 7, wherein the portion of the detector inlet is arranged to provide one or more light sources and / or one or more optical detectors with optical access to the sample receiving surface.

9. The sampling system of claim 7 or 8, wherein the portion of the detector inlet comprises one or more apertures in the detector inlet.

10. A sampling system according to any preceding claim, wherein the system comprises a heater for heating the sample receiving surface, optionally wherein the heater is operable to dislodge accumulated material from the sample receiving surface.

11. A sampling system according to any preceding claim, wherein the ion analyser sampling inlet comprises a pinhole inlet.

12. A sampling system according to any preceding claim, wherein the sampling system is for an ion analyser comprising an ion mobility spectrometer IMS or a mass spectrometer MS.

13. A detection device for detecting a substance of interest, the device comprising: A sampling system according to any one of the preceding claims; an ion analyser having an ioniser, wherein the ion analyser is coupled to the sampling system and arranged to identify the presence of one or more substances of interest in the first sample provided to the ion analyser through the ion analyser sampling inlet of the sampling system; as well as An optical analyzer is coupled to the sampling system and is arranged to identify the presence of one or more substances of interest in the second sample received by the sample receiving surface of the sampling system. The detection device according to claim 13 , wherein the ion analyzer comprises IMS or MS.

15. A detection device according to claim 13 or 14, wherein the device is arranged such that the first sample and second sample are provided from the same volume of air flowing through the detector inlet of the sampling system.

16. The detection device according to any one of claims 13 to 15, wherein the device is configured to selectively control the following operations: (i) the operation of the optical analyzer based on the ion analyzer, or (ii) the operation of the ion analyzer based on the optical analyzer.

17. A detection device according to any one of claims 13 to 16, wherein the device is configured to determine the presence of a substance of interest in the air from the detector inlet of the sampling system based on analysis performed by both the ion analyser and the optical analyser.

18. A detection device according to claim 17, wherein the device is configured to identify the presence of the substance of interest in the air from the detector inlet of the sampling system when both of the following occur: (i) the analysis performed by the ion analyzer indicates the presence of the substance of interest, and (ii) the analysis performed by the optical analyzer indicates the presence of the substance of interest.

19. A detection device according to claim 17 or 18, wherein the device is configured to determine the absence of the substance of interest in at least one of the following situations: (i) the analysis performed by the ion analyzer indicates the absence of the substance of interest, and (ii) the analysis performed by the optical analyzer indicates the absence of the substance of interest.

20. The detection device according to any one of claims 13 to 19, wherein at least one of the following: the apparatus being configured to control operation of the ion analyser to identify the presence of one or more substances of interest in the first sample, and where substances of interest in the first sample are identified using the ion analyser, the apparatus being configured to control operation of the optical analyser to identify the presence of the substances of interest in the second sample; and The device is configured to control the operation of the optical analyzer to identify the presence of one or more substances of interest in the second sample, and when the substances of interest in the second sample are identified using the optical analyzer, the device is configured to control the operation of the ion analyzer to identify the presence of the substances of interest in the first sample.

21. A detection device according to any one of claims 13 to 20, wherein the device is handheld, optionally wherein the device is battery powered.

22. A method of controlling the operation of a sampling system for a detection device, the detection device comprising: (i) an ion analyzer having an ionizer, and (ii) an optical analyzer for detecting a substance of interest on a sample receiving surface, wherein the method comprises: flowing air through a detector inlet of the sampling system; taking a first sample from the detector inlet and providing the first sample to an ionizer of an ion analyzer; and A second sample is received from the detector inlet on a sample receiving surface in the detector inlet.

23. A method of controlling the operation of a detection device to identify the presence of one or more substances of interest in a volume of air flowing through a detector inlet of a sampling system of the detection device, the method comprising at least one of: operating an ion analyzer to identify the presence of one or more substances of interest in a first sample obtained from the detector inlet, and, if the ion analyzer identifies the presence of the one or more substances of interest in the first sample, operating an optical analyzer to identify the presence of the one or more substances of interest in a second sample received on a sample receiving surface in the detector inlet; and An optical analyzer is operated to identify the presence of one or more substances of interest in a second sample received on a sample receiving surface in the detector inlet, and when the optical analyzer identifies the presence of one or more substances of interest in the second sample, an ion analyzer is operated to identify the presence of the one or more substances of interest in a first sample obtained from the detector inlet.

24. A method of detecting the presence of a substance of interest in a volume of air flowing through a detector inlet of a sampling system, the method comprising: determining whether a first substance of interest is present in a first sample obtained from the detector inlet based on ion analyzer data from an ion analysis of the first sample; determining whether the first substance of interest is present in the second sample based on optical analyzer data from optically analyzing a second sample received on a sample receiving surface in the detector inlet; as well as In the event that it is determined that the first substance of interest is present in both the ion analyzer data and the optical analyzer data, an indication is given that the first substance of interest is present.

25. A computer program product comprising computer program instructions configured to program a controller to control the operation of an apparatus to perform the method according to any one of claims 22 to 24.

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