Cold trap enhanced input into low-cost analyzer
Inventors
Smith, Barry T. • Brady, John • Barber, Jeffrey
Assignees
US Department of Homeland Security
Publication Number
US-11709149-B2
Publication Date
2023-07-25
Expiration Date
2042-09-07
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Abstract
Examples are directed toward systems and methods relating to collecting and analyzing samples. For example, a system includes a cold trap that directly collects a sample. The cold trap operates to serve as a collection filter while the system draws in a flow across the cold trap. A thermal heater, coupled to the cold trap, flash heats the cold trap to produce a released sample from the cold trap at a release concentration. An analyzer entrains the released sample at the release concentration into a sampling flow of the analyzer for analysis.
Core Innovation
The invention relates to systems and methods for collecting and analyzing samples, specifically using a cold trap that directly collects a sample while the system draws a flow across it. The cold trap serves as a collection filter and is coupled with a thermal heater that flash heats the cold trap to produce a released sample at a release concentration. An analyzer then entrains this released sample into its sampling flow for analysis.
The problem being solved involves the difficulty in detecting contraband vapors or suspended particles, like explosives or illicit drugs, which often exist in very low concentrations. Existing air samplers use collection filters to concentrate these vapors, but even these filters may collect only low mass amounts, necessitating expensive and high-performance detection equipment such as GC-MS systems. Budgetary or other constraints often make such high-performance equipment unavailable.
The invention provides an improved detection system where a high-volume sampler filter collects the sample, which is thermally desorbed by a thermal desorber. The released sample is captured by a cold trap operated as a collection filter, which can be rapidly heated by an integrated thermal heater to release a concentrated sample directly into a low-cost analyzer, like an ion mobility spectrometer or a non-triple quadrupole mass spectrometer. This approach enables effective detection of low concentration vapors at a reduced cost compared to traditional high-end analytical equipment.
Claims Coverage
The patent defines two main independent claims covering systems and methods involving thermal desorption, cold trap collection, flash heating, and sample analysis with low-cost analyzers. The inventive features relate primarily to how the sample is collected, concentrated, released, and introduced into the analyzer.
Thermal desorption and cold trap concentration system
A system including a thermal desorber that heats a high-volume sampler concentrating filter to release the collected sample, a cold trap that collects the sample while a flow is drawn across it, a thermal heater coupled to the cold trap that flash heats it to produce a released sample at a release concentration, and an analyzer that entrains and analyzes the released sample.
Integration of system components with controlled sampling flow
A system including a thermal desorber to heat a high-volume sampler concentrating filter, a valve to controllably release the sample into a sampling flow, a cold trap that directly collects the sample from the sampling flow, a thermal heater coupled to the cold trap for flash heating, an analyzer for analysis, and a controller directing the operation of these components.
Methods for sample collection, thermal desorption, and entrainment
Methods involving loading a high-volume sampler filter into a thermal desorber, heating it to release the sample, operating a cold trap to collect the released sample, flash heating the cold trap to produce the sample at a release concentration, and entraining the sample into an analyzer’s sampling flow for detection.
The independent claims collectively disclose systems and methods that leverage thermal desorption of concentrated filters, cold trap collection and rapid flash heating, and subsequent entrainment into analyzers. These inventive features enable sensitive detection of low concentration vapors by enhancing sample concentration and timing for low-cost analyzers.
Stated Advantages
Enables detection of low concentration vapor or suspended particles using relatively inexpensive analyzers such as ion mobility spectrometers or low-cost mass spectrometers instead of expensive high-performance detection equipment.
Provides a cost-effective alternative to high-cost analytical equipment by concentrating contraband vapors and timing the sample release for enhanced detection.
Improves sample transfer and prevents sample loss or background contamination by heating system components above ambient temperature and using chemically inert or passivated materials.
Allows operation with thermal desorption ramps and hold times to selectively release and detect different volatile compounds.
Documented Applications
Detection of contraband substances such as explosives, propellants, and illicit drugs by sampling vapors or suspended particles released into the vapor phase.
Sampling air or gases from environments suspected to contain concealed contraband by using high-volume samplers and thermal desorption.
Use in systems including ion mobility spectrometers or low-cost mass spectrometers for analyzing samples released from high-volume sampler filters and cold traps.
Direct sampling of ambient air vapor by operating a cold trap as a filter to enable detection without requiring a separate filter or thermal desorber component.
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