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AssigneeThe Johns Hopkins University
InventorsWayne A. Bryden, Peter F. Scholl, Micah A. Carlson, Michael P. McLoughlin
Estimating the term…
A method and apparatus for particle collection (30) that is characterized by co-aerosolizing fluids (62) into an air stream (34) containing the particles to be analyzed to significantly enhance their collection and identification efficiency is provided.
A method for particle collection comprising the steps of:
A method for particle collection comprising the steps of:
A method for particle collection comprising the steps of:
The method for particle collection comprising the steps of:
An apparatus for collecting particles carried by an air stream, comprising:
An apparatus for collecting particles carried by an air stream, comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Investigating particle size or size distribution: with mechanical, e.g. inertial, classification, and investigation of sorted collections
In the gaseous state: involving separation of sample components during sampling
Investigating concentration of particle suspensions: using condensation nuclei counters
In the gaseous state: suction devices
Term ended 4 May 2023 (estimated)
1. Field of the Invention
The present invention generally relates to a sampling methodology. More particularly, the present invention is directed to a method and apparatus for improving capturing efficiency of airborne particulates and for providing immediate sample treatments which serve to enhance post-collection detection or identification systems.
2. Description of the Related Art
The above and other objects, features and advantages will become more readily apparent from a detailed description of the preferred embodiment of the present invention accompanied by the following drawings, in which:
FIG. 1 is a diagrammatic view illustrating an inventive process; and,
FIG. 2 is a schematic view of an inventive device configured to carry out the inventive process.
Referring to FIGS. 1 and 2, the inventive process 10 is configured to coagulate particles, particularly particles smaller than about 1 micrometer, with aqueous droplets to form larger particles that can be captured with much grater efficiency. Particularly, as denoted by box 12 in FIG. 1, an air stream 34 carrying particles to be analyzed is guided via a particle concentrator 24 (FIG. 2) towards an impaction-based sampler/collector 30 that can be a virtual air-air impactor or an air-surface (real) impactor. Finally, the concentrated air-stream is intercepted by an impaction surface 26, which, depending on a particle-analysis method, such as mass spectrometry, PCR, or culturing, may be a bare displaceable tape, metal surface, or a fluid reservoir, as will be discussed hereinbelow. As the air stream 34 advances along a flow path, an aerosol 62, generated at 14 by an aerosol generator 22, entrains the particles carried by the air stream. As a result of the aerosol introduction, particles carried by the air stream 34, even small particles having a size less than 1 micrometer, are co-aerosolized.
The co-aerosolization of the air stream triggers two particularly important mechanisms leading to the enhanced collection efficiency. First, aqueous droplets merge with small particles, which, thus, increase their aerodynamic diameter to form a target that can be relatively easily caught by the impaction surface 26. Second, since the enlarged particles hitting the surface 26 are wet, they do not bounce off the solid surface of the bare tape as easily as dry particles and remain “stuck” on the impaction surface. The combination of these mechanisms leads to an enhanced overall collection efficiency and sample spot localization with reference to the impaction surface 26, particularly in case of the bare tape or any other solid surface made from, for example, metal, as indicated by box 18 in FIG. 1.
The fluid co-aerosolization provides an enhanced capability for sample collection for a variety of analytical methods including, but not limited to a mass spectrometry based detection system 20 (FIG. 1), which is disclosed in U.S. application Ser. No. 10/030,396, filed Jan. 8, 2002, the contents of which are incorporated herein by reference. Briefly, the detection system 20 may comprise a laser configured to ionize the collected particulates (sample) from the tape located adjacent to a vacuum interface of mass spectrometer. Note, however, the inventive method can be applied to nearly all types of particulate collection including those that utilize a liquid impaction surface. The inventive method, carried out by an apparatus, as shown in FIG. 2, enhances the sample collection efficiency and spot localization that at least one order of magnitude higher than uncoated polymer substrates. Another benefit of implementing the aqueous co-aerosolization protocol is that the solid impaction surface 26, such as the tape, is mechanically easy to handle.