Patent Description:
The invention concerns a trace analyte collection swab according to claim <NUM> and a trace analyte collection method according to claim <NUM>.

The use of the same reference number in different instances in the description and the figures may indicate similar or identical items.

The collection (or harvesting) efficiency of trace analyte collection swabs varies for different chemicals being collected, for the swab material being used, and for different surfaces being swabbed. In some instances, the efficiency of collection of trace analytes from a surface using a conventional collection swab can be very low or zero for some chemicals. For example, where swabs made from NOMEX or Sharkskin materials are used to collect Trinitrotoluene (TNT), a dry chemical, from a vinyl (e.g., "leatherette") surface, the collection or harvesting efficiency is virtually zero (<NUM>) even at fifty (<NUM>) times the minimum alarm level capability of a conventional detector.

Consequently, it is desirable to improve the collection efficiency of conventional swabs. The National Institute for Science and Technology (NIST) described a method of increasing the collection efficiency of twenty-four micrometer (<NUM>) polymeric spheres doped with one-half percent (<NUM>%) explosive. The method described used a tacky (to the touch) silicone material CV3-<NUM> manufactured by NuSil. NIST obtained significant improvement in pickup efficiency for the polymer spheres using the silicone tacky material. However, the use of NuSil CV3-<NUM> silicone at <NUM>% loading on the swab surface leaves behind discernible streaks of silicone on the substrate surface following swabbing. When coating material is left behind on the sampled substrate, the collected explosive may also be left behind on the surface. Additionally, NuSil CV3-<NUM> and similar two-part adhesives are difficult to use, in that such two-part adhesives require that precise quantities of the polymer base and the catalyst be thoroughly mixed prior to application. Moreover, the catalyst must be stored at below freezing (< 0C) temperatures. Further, the pot-life of the mixed silicone adhesive is short - on the order of a few hours. Still further, the final coating of the adhesive must be cured at an elevated temperature. NuSil CV3-<NUM> and other <NUM>-part adhesives also contain a peroxide catalyst which is a hazardous substance.

Accordingly, a trace analyte collection swab having a collection surface at least partially coated with a microscopically tacky substance to enhance pick-up efficiency is described. In embodiments, the trace analyte collection swab comprises a substrate including a surface having a trace analyte collection area and a coating disposed on the surface of the substrate in the trace analyte collection area. The coating is configured to be microscopically adhesive to collect particles of the trace analyte from a surface when the trace analyte collection area is placed against the surface.

In embodiments, the coating comprises Polyisobutylene (PIB). The coating may be applied in a pattern on the substrate in the trace particle collection area. The pattern may comprise one or more first areas where the coating is applied and one or more second areas where the coating is not applied. The one or more first areas are configured to collect particles of a trace analyte of a first type, while the one or more second areas are configured to collect particles of a trace analyte of a second type that are collected with a low collection efficiency, or that are not collected by the at least one first area. In embodiments, the substrate has a first color and the coating has a second color, wherein the second color is different than the first color.

In embodiments, the coating includes a dopant. The dopant may comprise a calibrating material for calibration of a detector. The dopant may comprise a reactant material configured to combine with a trace analyte when the swab is placed against a surface. The dopant may comprise a tracer material that can be used to indicate characteristics of the swab. The dopant may comprise a vapour-collecting material configured to collect particles of a trace analyte in vapour form.

In embodiments, the substrate comprises paper, filter paper (e.g., SHARKSKIN filter paper manufactured by Whatman Corporation), an aramid polymer material (e.g., NOMEX material manufactured by E. du Pont de Nemours and Company), and so forth. The substrate may be attached to a sampling wand. In other embodiments, the substrate comprises one or more bristles of a brush. The substrate may be provided with an identifier such as a barcode, Radio Frequency Identification (RFID) tag, and so forth, for furnishing identification of the swab. For example, in an embodiment, the substrate comprises a portion of a document such as a boarding pass, ticket, and so forth. The boarding pass may include an identifier such as a bar code configured to associate the particles of a trace analyte collected by the coating with the holder of the boarding pass. Similarly, in another embodiment, the substrate comprises a portion of package. The package may include a bar code configured to associate a trace analyte collected by the coating with the mailer and/or recipient of the package.

In embodiments, a plurality of substrates may be detachably joined together in a trace analyte collection swab dispensing system configured to dispense individual swabs.

Example implementations of trace analyte detection swabs will now be described with reference to the accompanying drawings.

<FIG> illustrate trace analyte collection swabs <NUM> in accordance with example embodiments of the present disclosure. As shown, the trace analyte collection swabs <NUM> comprise a substrate <NUM> including a surface having a trace analyte collection area <NUM> and a coating <NUM> disposed on the surface of the substrate <NUM> in the trace analyte collection area <NUM>. In embodiments, the coating <NUM> may be disposed on the surface of the substrate <NUM> by coating the coating material onto the surface, depositing the coating material onto the surface, spraying the coating material onto the surface, soaking the coating material into the substrate <NUM> through the surface, combinations thereof, and so forth. Thus, a coating <NUM> disposed on the surface of the substrate <NUM> of a trace analyte collection swab <NUM> may be placed on the surface of the substrate <NUM> and/or may be soaked into the surface of the substrate <NUM>.

In embodiments, the substrate <NUM> comprises a suitable substrate material such as paper, filter paper (e.g., SHARKSKIN filter paper manufactured by Whatman Corporation), an aramid polymer material (e.g., NOMEX material manufactured by E. du Pont de Nemours and Company), and so forth. The substrate <NUM> may be configured to be received by a chemical/explosives detector which may employ any of a variety of detection technologies including: ion mobility spectrometry (IMS), mass spectrometry, gas chromatography, liquid chromatography, high performance liquid chromatography (HPLC), combinations thereof, and so forth. For example, in the embodiment shown, the substrate <NUM> comprises a generally rectangular strip of the substrate material (e.g., paper, filter paper, aramid polymer material, etc.) which may be placed against a surface to collect particles of one or more trace analytes, and then inserted into a detector where collected particles are desorbed. In a specific example of this embodiment, the substrate <NUM> may comprise a strip of substrate material having a length of <NUM> (<NUM> in) and a width of <NUM> (<NUM> in). In this example, the substrate material may comprise paper having a paper weight of approximately <NUM> gsm (<NUM> lb). However, it is contemplated that the substrate material may comprise papers having paper weights greater or less than <NUM> gsm (<NUM> lb). Moreover, it is contemplated that the substrate material may also comprise filter paper, an aramid polymer material, combinations thereof, and so forth. Further, it is contemplated that the substrate <NUM> may have other shapes (e.g., square, oval, triangular, circular, irregular, etc.). The surface of the substrate <NUM> can be smooth or roughened.

In embodiments, the substrate <NUM> may be configured for attachment to a sampling wand. For example, an adhesive may be disposed on the surface of the substrate opposite the coating <NUM> (e.g., on the reverse side of the trace analyte collection area <NUM> of the substrate <NUM>) to facilitate attachment of the swab <NUM> to and/or removal of the swab <NUM> from a sampling wand (not shown).

The coating <NUM> is configured to be microscopically adhesive to collect particles of the trace analyte from a surface when the trace analyte collection area <NUM> is placed (e.g., pressed) against the surface. In embodiments, the coating comprises Polyisobutylene (PIB) having a formulation such as PIB 4T or other PIB formulations, The PIB may have a molecular weight of approximately <NUM>,<NUM> GPC (Gel Permeation Chromatography). PIB (e.g., PIB 4T or other PIB formulation) is not hazardous to humans or animals, can be stored at room temperature indefinitely, readily dissolves in hexane, is stable in solution, and has substantially no pot-life.

The coating <NUM>, which, in embodiments, comprises PIB (e.g., PIB 4T or other PIB formulation), is not perceptibly tacky or sticky (e.g., the coating <NUM> is dry-to-the-feel) and does not adhere to the surface being sampled, but is microscopically adhesive (e.g., microscopically sticky or tacky) to particles of the trace analyte. Additionally, the coating <NUM> leaves no residue when the trace analyte collection area <NUM> is placed against the surface to be swabbed. For dry particles, the coating <NUM> improves the collection (pick-up or "harvesting") efficiency of the swab <NUM> from the surface being swabbed compared to swabs that are not provided with the coating <NUM>. The coating <NUM> microscopically adheres the collected particles of the trace analyte to the swab <NUM> so that collected particles do not become dislodged and fall from the swab <NUM> during detection. Moreover, the coating <NUM> may retain volatile trace chemicals that would otherwise rapidly evaporate. The coating <NUM> withstands exposure to high temperatures without degradation, permitting use of the trace analyte collection swab <NUM> with a heated detector. Further, the coating, when heated, has limited or no outgassing of volatile materials that might otherwise contaminate a collected sample.

In embodiments, the coating <NUM> comprises a dopant such as a trace chemical that may be subsequently released during desorption by the detector. It is contemplated that a variety of dopants may be applied to the coating <NUM>. For example, in an embodiment, the dopant may comprise a calibrating material for calibration of a detector. In another embodiment, the dopant may comprise a reactant material configured to combine with the particles of trace analyte when the swab <NUM> is placed against a surface to be sampled. The reactant material may, for example, help to collect particles of a trace analyte from a surface, help to adhere particles of a trace analyte to the swab <NUM>, and/or help to desorb particles of a trace analyte from the swab <NUM>. In another embodiment, the dopant may comprise a vapour-collecting material configured to collect particles of the trace analyte in vapour form which are subsequently released upon heating or desorption. Example vapour-adsorbing materials include charcoal, a chromatographic absorption material such as TENAX, and so forth. In another embodiment, the dopant may comprise a tracer material that can be used to indicate characteristics of the swab <NUM> when desorbed. For example, the coating <NUM> may be doped with a tracer material to verify the authenticity of the swab <NUM>. The coating <NUM> may also be doped with a tracer material to indicate the suitability of the swab for collecting the trace analyte. The coating may further be doped with a tracer material that indicates the life of the swab <NUM> in multiple use applications (e.g., indicates when the swab <NUM> has exceeded its useful life). The coating <NUM> may also be doped with a tracer material to furnish a valid minimum response when used in combination with a detector to indicate correct operation of the detector.

In embodiments, the coating <NUM> is applied over a limited portion (e.g., area) of the trace analyte collection area <NUM> so that collected particles of trace analyte are concentrated for delivery to a detector for desorption of the trace analyte. For example, the position and area covered by the coating <NUM> may at least substantially match the position and area of the inlet opening of the detector with which the swab <NUM> is used. In the embodiment illustrated in <FIG>, the coating <NUM> is applied over a circular area of the trace analyte collection area <NUM> of the substrate <NUM>. In one specific example, the circular area has a diameter of approximately <NUM> (<NUM> in). However, it is contemplated that the portion of the substrate <NUM> over which the coating <NUM> is applied may have other shapes and surface areas.

In embodiments, the coating <NUM> is applied in a pattern <NUM> on the substrate <NUM> in the trace particle collection area <NUM>. <FIG> illustrate example trace analyte collection swabs <NUM>, wherein the coating <NUM> is patterned. As shown, the pattern <NUM> may comprise one or more first areas <NUM> where the coating <NUM> is applied and one or more second areas <NUM> where the coating is not applied. The one or more first areas <NUM> are configured to collect particles of a trace analyte of a first type, while the one or more second areas are configured to collect particles of a trace analyte of a second type. Thus, for example, the coating <NUM> may be applied to one or more first areas <NUM> to collect particles of dry chemicals such as TNT which do not efficiently adhere to the uncoated swab surface, while the second areas <NUM> where the coating is not applied may collect particles of sticky trace chemicals that adhere to the uncoated swab surface more efficiently than to the coating <NUM>, or do not adhere to the coating <NUM>. Additionally, the second areas <NUM> allow the swab surface to be exposed so that the swab material, which may be absorbent, can wick away traces of moisture that might otherwise contaminate or suppress the collection of trace analytes. Moreover, patterning of the coating <NUM> can facilitate printing of indicia such as, directions for use of the swab, a barcode, a logo or other marketing information, and so forth. <FIG> illustrate different coating patterns <NUM>. In <FIG>, the coating <NUM> is patterned so that the first areas <NUM> and the second areas <NUM> comprise interspersed concentric rings (e.g., the coating <NUM> is patterned in a "target" pattern). In <FIG>, the first areas <NUM> and the second areas <NUM> are arranged in alternating squares (e.g., the coating <NUM> is patterned in a "checkerboard" pattern <NUM>). In <FIG>, the first areas <NUM> and the second areas <NUM> are patterned in alternating strips (e.g., the coating <NUM> is patterned in a spaced-apart bar pattern <NUM>). Other patterns <NUM> may also be employed.

In embodiments, the coating <NUM> may be clear or translucent. In other embodiments, the coating <NUM> may be tinted so that the substrate <NUM> may have a first color and the coating <NUM> may have a second color, wherein the second color is different than the first color. In this manner, coating <NUM> of the swab <NUM> may function to indicate which side of the swab <NUM> to use to collect a sample, the location on the substrate <NUM> to which to apply swabbing pressure (e.g., on the surface opposite the coating <NUM> behind the trace analyte collection area <NUM>), the correct location of the swab <NUM> in a sampling wand, and so forth. <FIG> illustrate example trace analyte collection swabs <NUM>, wherein the substrate <NUM> has a first color and the coating <NUM> has a second color different than the first color. In <FIG>, the coating <NUM> is applied over a circular area and is shown as being tinted blue against a white substrate <NUM>. In <FIG>, the coating <NUM> is patterned with a checkerboard pattern <NUM> having first areas <NUM> provided with the coating <NUM> and second areas <NUM> without the coating <NUM>. The coating <NUM>, applied in the second areas <NUM> is shown as being tinted red against a white substrate <NUM> in the first areas <NUM>. However, it is contemplated that the coating <NUM> may be tinted in other colors, combinations of colors (e.g., green and yellow, red and blue, a multicolored logo, etc.), and so forth.

In embodiments, the substrate <NUM> of the trace analyte collection swab <NUM> may be provided with an identifier <NUM>, which may be machine readable, such as a barcode, a Radio Frequency Identification (RFID) tag or patch, identification indicia, combinations thereof, and so forth, for furnishing identification of the swab <NUM>. For example, in <FIG>, the substrate <NUM> is illustrated as including an identifier <NUM> comprised of a two dimensional (2D) barcode. In embodiments, the identifier <NUM> may be used to verify the authenticity of the swab <NUM>, to indicate the suitability of the swab for collecting the trace analyte, to indicate the life of the swab <NUM> in multiple use applications (e.g., indicates when the swab <NUM> has exceeded its useful life), and so forth.

In embodiments, a plurality of substrates <NUM> may be detachably joined together in a trace analyte collection swab dispensing system configured to dispense individual swabs <NUM>. <FIG> illustrate trace analyte collection swab dispensing systems <NUM>, <NUM> in accordance with example embodiments of the present disclosure.

In the embodiment shown in <FIG>, the trace analyte collection swab dispensing system <NUM> comprises a plurality of substrates <NUM> detachably joined together in a stacked arrangement. For example, a releasable adhesive <NUM> may be applied to an end portion of the surfaces of respective substrates <NUM> opposite the trace analyte collection area <NUM> and coating <NUM> (e.g., the backside of the swab <NUM>). However, it is contemplated that, in embodiments, the coating <NUM> could be made sufficiently tacky to join the substrates <NUM> together without the use of an additional releasable adhesive <NUM>. The releasable adhesive <NUM> (or tacky coating <NUM>) is configured to detachably join the bottom surface respective substrates <NUM> to the top surface of an adjacent substrate <NUM> in the stacked arrangement. In this manner, the surface of the substrate <NUM> on which the coating <NUM> is disposed is occluded and thus protected from contamination. By occluding or protecting the surface of the substrate <NUM> containing the coating <NUM>, the cleaning processes typically employed for cleaning raw-material swabs in order to make them suitable for use as a trace detection swab may be reduced or eliminated.

As shown in <FIG>, the substrates <NUM> of the respective trace analyte collection swabs <NUM> may be provided with an identifier <NUM>, which may be machine readable, such as a barcode, an RFID tag or patch, identification indicia, combinations thereof, and so forth, for furnishing identification of the swab <NUM>. In embodiments, the identifier <NUM> may be used to verify the authenticity of a swab <NUM> when dispensed, to indicate the suitability of the swab for collecting the trace analyte, and so forth. In embodiments, the substrates <NUM> of the respective trace analyte collection swabs <NUM> may be configured for attachment to a sampling wand. For example, an adhesive may be disposed on the surface of the respective substrates <NUM> opposite the coating <NUM> (e.g., on the reverse side of the trace analyte collection area <NUM> of the substrate <NUM>) to facilitate attachment of the swab <NUM> to and/or removal of the swab <NUM> from a sampling wand (not shown).

In the embodiment shown in <FIG>, the trace analyte collection swab dispensing system <NUM> comprises a dispensing apparatus <NUM> containing a roll <NUM> of trace analyte collection swabs <NUM>, wherein the respective substrates <NUM> of the swabs <NUM> are joined end-to-end via a perforated section <NUM> (which may be generally V-shaped) within the roll <NUM>. The perforated sections <NUM> allow individual swabs <NUM> to be separated from the roll <NUM> for use. Again, the surface of the substrate <NUM> on which the coating <NUM> is disposed is occluded and thus protected from contamination so that the cleaning processes typically employed for cleaning raw-material swabs in order to make them suitable for use as a trace detection swab may be reduced or eliminated.

The trace analyte collection swab <NUM> may be fabricated as part of, or may be attached to, another item or device that could be handled by an individual leaving trace materials. In embodiments, the trace analyte collection swab <NUM> may comprise a portion of, or may be attached to, a document such as an airline boarding pass, a ticket, and so forth. For example, as shown in <FIG>, the substrate <NUM> of the trace analyte collection swab <NUM> is illustrated as comprising a portion of an airline boarding pass <NUM>. In the embodiment illustrated, the boarding pass <NUM>, or a portion thereof, is fabricated of a suitable substrate material as described above and may include a portion <NUM> that is retained by the airline, a governmental body such as the United States Transportation Security Administration (TSA), and so forth, and a portion <NUM> that is provided to the traveler prior to boarding an aircraft. As shown, the retained portion <NUM> includes a trace analyte collection area <NUM> positioned in an area of the boarding pass likely to be handled by the traveler and a coating <NUM> disposed on the surface of the substrate <NUM> in the trace analyte collection area <NUM> to collect trace analytes from the hands of the traveler for detection and/or analysis. In other embodiments, the trace analyte collection swab <NUM> may comprise a portion of the boarding pass <NUM> that is removed and retained by the airline, governmental body, and so forth (e.g., a peelable sticker, a perforated section, and so forth), such as for analysis. The boarding pass <NUM> may further include an identifier <NUM> such as a bar code, RFID tag or patch, or the like, configured to associate the particles of a trace analyte collected by the coating <NUM> with the holder of the boarding pass <NUM>.

In other embodiments, the trace analyte collection swab <NUM> may comprise a portion of, or be attached to, a mailed item such as an envelope, package, and so forth. For example, as shown in <FIG>, the substrate <NUM> of the trace analyte collection swab <NUM> is illustrated as comprising a portion of a package <NUM>. In the embodiment illustrated, the package <NUM>, or a portion thereof such as a flap <NUM>, is fabricated of a suitable substrate material as described above. However, in other embodiments, the substrate <NUM> may be adhered to the package <NUM> (e.g., via a peelable sticker, address label, stamp, and so forth), which may later be removed from the package <NUM>, such as for analysis. As shown, the package <NUM> includes a trace analyte collection area <NUM> (e.g., flap <NUM>) positioned in a portion of the package likely to be handled by the mailer (e.g., a person depositing the package in the mail, a person handling the package prior to mailing, and so forth) when sealing the package and a coating <NUM> disposed on the surface of the substrate <NUM> in the trace analyte collection area <NUM> to collect trace analytes from the hands of the mailer for detection and/or analysis. In embodiments, the package <NUM> may further include an identifier <NUM> such as a bar code, RFID tag or patch, or the like, configured to associate the particles of a trace analyte collected by the coating <NUM> with the mailer and/or a recipient of the package <NUM>.

In the embodiments described above, the substrate <NUM> of the trace analyte collection swab has comprised a generally flat sheet of substrate material. However, it is contemplated that the substrate <NUM> need not necessarily be limited to this form factor. For example, the substrate <NUM> may be formed of a sheet of substrate material that is shaped (e.g., folded, rolled, embossed, etc.) into a three dimensional shape (e.g., a cylinder, a cone, etc.). When formed into a three dimensional shape, the substrate <NUM> may be attached to a sampling wand, which may be configured to allow the trace analyte collection swab <NUM> to be rolled against a surface to collect analyte from the surface,.

For example, <FIG> illustrates a trace analyte collection swab <NUM> that includes a substrate <NUM> that is generally triangular (e.g., pie-shaped). As shown, the substrate <NUM> may be rolled into a cone having an outer surface that forms the trace analyte collection area <NUM> and a coating <NUM> disposed on the substrate <NUM> (e.g., on the outer surface of the cone) in the trace analyte collection area <NUM>.

Additionally, it is contemplated that non-sheet form factor substrates <NUM> may be used. For example, shown in <FIG>, the trace analyte collection swab <NUM> illustrated comprises a brush <NUM>. In this embodiment, the substrate is comprised of the bristles <NUM> of the brush <NUM>, which may be coated with a coating <NUM> for collection of particles of trace analyte from a surface. The coating <NUM> is configured to be microscopically adhesive to collect particles of the trace analyte from a surface when the bristles <NUM> of the brush are placed (e.g., brushed) against the surface. In embodiments, the coating comprises Polyisobutylene (PIB) having a formulation such as PIB 4T or other PIB formulations. The PIB may have a molecular weight of approximately <NUM>,<NUM> GPC (Gel Permeation Chromatography). PIB (e.g., PIB 4T or other PIB formulation) is not hazardous to humans or animals, can be stored at room temperature indefinitely, readily dissolves in hexane, is stable in solution, and has substantially no pot-life.

The coating <NUM>, which, in embodiments, comprises PIB (e.g., PIB 4T or other PIB formulation), is not perceptibly tacky or sticky (e.g., the coating <NUM> is dry-to-the-feel) and does not adhere to the surface being sampled, but is microscopically adhesive (e.g., microscopically sticky or tacky) to particles of the trace analyte. Additionally, the coating <NUM> leaves substantially no residue when the bristles <NUM> of the brush are placed (e.g., brushed) against the surface to be swabbed. The coating <NUM> thus improves the collection (pick-up or "harvesting") efficiency of the swab <NUM> from the surface being swabbed compared to swabs that are not provided with the coating <NUM>. The coating <NUM> microscopically adheres the collected particles of the trace analyte to the bristles <NUM> of the swab <NUM> so that collected particles do not become dislodged and fall from the swab <NUM> during detection. Moreover, the coating <NUM> may retain particles of volatile trace chemicals that would otherwise evaporate. The coating <NUM> withstands exposure to high temperatures without degradation, permitting use of the trace analyte collection swab <NUM> with a heated detector. Further, the coating, when heated, has limited or no outgassing of volatile materials that might otherwise contaminate a collected sample.

In embodiments, the coating <NUM> comprises a dopant such as a trace chemical that may be subsequently released during desorption by the detector. It is contemplated that a variety of dopants may be applied to the coating <NUM>. For example, in an embodiment, the dopant may comprise a calibrating material for calibration of a detector. In another embodiment, the dopant may comprise a reactant material configured to combine with the particles of trace analyte when the swab <NUM> is placed against a surface to be sampled. The reactant material may, for example, help to collect particles of a trace analyte from a surface, help to adhere particles of a trace analyte to the swab <NUM>, and/or help to desorb particles of a trace analyte from the swab <NUM>. In another embodiment, the dopant may comprise a vapour-collecting material configured to collect particles of the trace analyte in vapour form which are subsequently released upon heating or desorption. Example vapour-collecting materials include charcoal, a chromatographic absorption material such as TENAX, and so forth. In another embodiment, the dopant may comprise a tracer material that can be used to indicate characteristics of the swab <NUM> when desorbed. For example, the coating <NUM> may be doped with a tracer material to verify the authenticity of the swab <NUM>. The coating <NUM> may also be doped with a tracer material to indicate the suitability of the swab for collecting the trace analyte. The coating may further be doped with a tracer material that indicates the life of the swab <NUM> in multiple use applications (e.g., indicates when the swab <NUM> has exceeded its useful life). The coating <NUM> may also be doped with a tracer material to furnish a valid minimum response when used in combination with a detector to indicate correct operation of the detector,.

In embodiments, the brush <NUM> can be capped so that particles of trace analyte collected remotely can be protected from subsequent contamination. The brush <NUM> may be capable of reuse (e.g., following a suitable cleaning process). In embodiments, the brush <NUM> is inserted into the inlet area of a detector directly, and heated radiatively or through convection. In other embodiments, the material from which the bristles <NUM> of the brush <NUM> are fabricated may be conductive to allow for resistive heating of the coated bristles <NUM>, providing increased control over the heating process. In this manner, heating at higher temperatures than would be achieved using a heated inlet may be possible. Additionally, the use of resistive heating may allow for temperature ramping at a much greater rate than is achievable using a ramped-temperature or fixed temperature inlet. In this manner, the release of the collected particles of trace analyte as vapour would be faster than with a ramped-temperature or fixed temperature inlet, providing a higher signal amplitude, and thus a better limit of detection.

Claim 1:
A trace analyte collection swab (<NUM>) comprising:
a substrate (<NUM>) comprising paper or an aramid polymer, the substrate comprising a surface having a trace analyte collection area (<NUM>); and
a coating (<NUM>) disposed on the surface of the substrate (<NUM>) in the trace analyte collection area (<NUM>), the coating (<NUM>) comprising polyisobutylene to collect particles of the trace analyte from a surface when the trace analyte collection area (<NUM>) is placed against the surface;
wherein the coating (<NUM>) is applied over a limited portion of the trace analyte collection area (<NUM>) so that collected particles of trace analyte are concentrated for delivery to a detector for desorption of the trace analyte.