Sampling system and process for sampling
Inventors
Assignees
National Institute of Standards and Technology NIST • United States Department of Commerce
Publication Number
US-9772263-B2
Publication Date
2017-09-26
Expiration Date
2033-08-23
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Abstract
A sampling system includes an analyte sampler that includes an enclosure; a mount disposed in the enclosure; a capillary tube disposed in the mount; and a thermal member disposed in the enclosure and including a first fluid supply member to provide a fluid to an interior of the enclosure. The sampling system also includes a manifold in fluid communication with the analyte sampler. A process for sampling an analyte includes subjecting the capillary tube to a negative pressure; and controlling the temperature of the capillary tube to immobilize the analyte in the capillary tube; providing an analyte to a second end of the capillary tube; and immobilizing the analyte in the capillary tube to sample the analyte.
Core Innovation
A sampling system includes an analyte sampler with an enclosure, a mount inside the enclosure, and a capillary tube disposed in the mount configured to receive an analyte. The sampling system further includes a thermal member disposed in the enclosure that pneumatically controls the temperature of the capillary tube by providing a fluid to the interior of the enclosure. A manifold is in fluid communication with the analyte sampler, and a flow member connects the manifold and the analyte sampler to communicate the fluid-carrying temperature control to the capillary tube.
The invention addresses the problem of sampling analytes, particularly at trace levels or with very low volatility, where longer collection times and efficient analyte immobilization in the sampling device are required. Conventional headspace sampling methods typically rely on positive pressure and static or dynamic approaches that may lack portability, robustness, or efficient thermal control, especially for field use outside laboratories.
Claims Coverage
The patent includes one independent claim covering a sampling system with multiple novel features addressing thermal control, fluid flow, and analyte sampling configurations.
Sampling system with pneumatically controlled thermal member
The sampling system comprises an analyte sampler with an enclosure, a mount housing a capillary tube configured to receive an analyte, and a thermal member that pneumatically controls the temperature of the capillary tube by providing fluid to the interior of the enclosure.
Flow member with countercurrent fluid flow and thermal insulation
The flow member interconnects the manifold and analyte sampler, including a second fluid supply member to communicate fluid to the sampling enclosure and a fluid return. The flow member is thermally insulated and includes a spacer arranged so that the fluid flows in the second fluid supply member counter to the fluid flow in the fluid return, improving thermal management.
Manifold incorporating negative pressure and temperature control via vortex tubes
The manifold integrates a vacuum member to generate a negative pressure applied to the capillary tube, and temperature control using first and second vortex tubes producing cold and hot fluids respectively. These fluids are communicated pneumatically to the thermal member controlling the capillary tube temperature.
Configurable analyte sampling with a probe and modular enclosure
The system includes a probe with a body, probe tip, and sampling orifice connected to the capillary tube for analyte acquisition. The enclosure can be a hand piece or sampling module providing portability and remote operation.
The independent claim covers a sampling system integrating a pneumatically temperature-controlled capillary tube within an analyte sampler, a thermally insulated flow member providing countercurrent fluid flow, a manifold providing vacuum and temperature regulation via vortex tubes, and a modular design including a probe for analyte acquisition, enabling efficient sampling and immobilization of analytes under controlled conditions.
Stated Advantages
The sampling system is field-portable, enabling remote vapor collection of analytes of high and medium volatility including polar solutes outside laboratory environments.
The system operates pneumatically using a compressed air source, eliminating electrical power requirements and spark sources, enabling safe use in explosive atmospheres compliant with National Electrical Code Class I Division I Groups A and B.
It supports multiple, consecutive uses in the field without analyzing collected analytes between sampling events and is self-cleaning through thermal desorption to prepare for subsequent sampling.
The analyte sampler is robust, rugged, and includes protective mounting of the capillary tube, providing a long operational lifetime with potential for serial or parallel use of multiple capillary tubes.
Documented Applications
Use in criminalistics for remote sampling at crime scenes.
Food safety applications involving remote analyte detection.
Environmental sampling, including vapor sampling in soil, beneath articles like concrete slabs, inside shipboard cargo containers, suitcases, motor vehicles, and similar environments.
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