US20030000318A1 - Apparatus for sampling & analysis of thermally-labile species and a method relating thereto - Google Patents
Apparatus for sampling & analysis of thermally-labile species and a method relating thereto Download PDFInfo
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- US20030000318A1 US20030000318A1 US10/232,368 US23236802A US2003000318A1 US 20030000318 A1 US20030000318 A1 US 20030000318A1 US 23236802 A US23236802 A US 23236802A US 2003000318 A1 US2003000318 A1 US 2003000318A1
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- quartz
- filter member
- tube
- beads
- sampling
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- Abandoned
Links
- 238000005070 sampling Methods 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 title abstract description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 53
- 239000010453 quartz Substances 0.000 claims abstract description 51
- 239000011324 bead Substances 0.000 claims abstract description 29
- 239000012530 fluid Substances 0.000 claims abstract description 14
- 238000010438 heat treatment Methods 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 6
- 239000000919 ceramic Substances 0.000 claims description 5
- 239000005350 fused silica glass Substances 0.000 claims 2
- 239000013618 particulate matter Substances 0.000 abstract description 16
- 239000011236 particulate material Substances 0.000 abstract description 12
- 239000000463 material Substances 0.000 abstract description 6
- 230000000717 retained effect Effects 0.000 abstract description 5
- 238000003795 desorption Methods 0.000 abstract description 4
- 239000007788 liquid Substances 0.000 abstract description 4
- 239000000126 substance Substances 0.000 abstract description 4
- 239000013626 chemical specie Substances 0.000 abstract description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 17
- 229910052753 mercury Inorganic materials 0.000 description 15
- 239000012494 Quartz wool Substances 0.000 description 11
- 239000000835 fiber Substances 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
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- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 239000012080 ambient air Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 150000007513 acids Chemical class 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000012159 carrier gas Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- -1 for example Substances 0.000 description 2
- 231100001261 hazardous Toxicity 0.000 description 2
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- 230000005526 G1 to G0 transition Effects 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000007825 activation reagent Substances 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
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- 150000007522 mineralic acids Chemical class 0.000 description 1
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- 230000003647 oxidation Effects 0.000 description 1
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- 229910052711 selenium Inorganic materials 0.000 description 1
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Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
- G01N15/0606—Investigating concentration of particle suspensions by collecting particles on a support
- G01N15/0618—Investigating concentration of particle suspensions by collecting particles on a support of the filter type
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
- G01N1/2205—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling with filters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/24—Suction devices
-
- G01N15/075—
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
- G01N2001/222—Other features
- G01N2001/2223—Other features aerosol sampling devices
Definitions
- This invention relates to an apparatus for sampling and analysis of thermally-labile species, such as mercury, arsenic, selenium, sulfur, lead, carbon, polyaromatic hydrocarbons, n-alkanes and the like, as may be associated with a variety of solid matrices (e.g., airborne particulate matter, suspended particles, soil materials, colloids).
- thermally-labile species such as mercury, arsenic, selenium, sulfur, lead, carbon, polyaromatic hydrocarbons, n-alkanes and the like
- solid matrices e.g., airborne particulate matter, suspended particles, soil materials, colloids
- Such devices include filter packs which collect the material(s) of interest and the filter(s) then being treated as, for example, by using one or more acids or oxidation reagents, with the resulting final solution then being analyzed.
- a quartz wool stationary phase is used to retain particulate material on a manually-loaded plug contained in a quartz tube. The tube, along with the collected sample, are heated to an elevated temperature and the released elements of interest are detected and quantified.
- a miniaturized device using a quartz fiber filter disc. Particulate material, suspended in one or more gases or liquids, is trapped on the filter disc, following which the device is heated and the released elements detected and quantified.
- the present invention provides a novel apparatus, and a method, which is efficient, economical and which can be easily automated.
- a device for trapping particulate material in a fluid (usually/generally gaseous) stream, such as ambient air, or other fluid media together with a pyrolyzer for sample pre-treatment prior to analysis.
- the present invention is suitable for sampling and analyzing mercury, for example, as well as other thermally-labile species.
- a device of the present invention comprises a quartz housing with a filter member having a quartz bead plug and bead retainers such as quartz frits positioned on either side of the quartz beads.
- the housing preferably in the form of a tube, is variable in length and in width.
- the porosity of the bead plugs may vary, as desired, depending on the size range of the particulate matter to be collected.
- the dimensions of the plug can vary as can the pore size of the quartz frits.
- a filter member comprising a quartz bead plug having quartz frits on either side thereof is loaded into a quartz housing e.g. a tube.
- a flow of fluid gas for example air containing airborne particulate material, is passed through the tube with particulate material being collected in the quartz bead plug.
- the whole unit may be positioned in a heating chamber where the tube and filter member are heated to a high temperature, for example up to 900° C. or up to 1200° C., for thermal desorption and subsequent analysis of the collected material by an analyzer located downstream of the sampling unit.
- FIG. 1 diagrammatically illustrates one form of a device
- FIG. 2 is a diagrammatic illustration of a system embodying a device as in FIG. 1;
- FIGS. 3, 4 and 5 illustrate diagrammatically slightly different systems as further examples. Common reference numerals are used where applicable.
- an apparatus comprises a quartz tube 10 , having an inlet 12 and an outlet 14 .
- a filter member or element designated generally as 16 , having a central plug 18 of quartz beads with a layer quartz frit 20 on each side.
- fluid flow enters at inlet 12 as indicated, exiting at 14 .
- particulate material in the gas (or liquid) is retained on the quartz beads.
- the flow is cut off.
- the tube 10 and contained member 16 is then heated to, to a selected temperature for example, 1200° C.
- the chemical species of interest, which are associated with the particulate material on the beads are thermally desorbed (either slowly or rapidly depending upon the rate of heating of the apparatus).
- the tube 10 is normally connected to an analyzer 22 and the tube itself can be positioned in a heating enclosure, for example, a suitable housing as indicated at 24 , for the heating thereof.
- a suitable housing for example, a suitable housing as indicated at 24 , for the heating thereof.
- any suitable heating device may be employed; preferably, the means of heating is a heater which surrounds the quartz housing or tube and may be in the form of heating wires, an infrared heating device, or a suitable microwave oven or cavity.
- the diameter and length of the tube 10 will vary depending upon the specific application. The larger the tube, the higher the flow rate, but too large a tube can result in insufficient heating, particularly at the center of the filter member 16 , as well as reducing the rate at which the tube is heated.
- the tube has a bore of between 10 and 20 mm., with the filter member 16 having a length of about 2 mm.
- the size of the quartz beads can vary depending upon the specific application. As a general rule, the smaller the particle size of the particulate matter to be collected, the smaller the size of the beads.
- the length of the quartz bead plug 18 should be long enough to retain all particulate material in the desired size range.
- the particulate filtration medium 18 may be in the form of quartz or ceramic beads which have a size of from about 8 to about 170 mesh, and more desirably from about 40 mesh to about 120; or between 80 and 170 mesh.
- the porosity of the quartz frits can vary depending upon the specific application. As a general rule, the pore size of the quartz frits 20 should be smaller than the size of the quartz beads 18 . Typically, the porosity of the quartz frits will vary from a porosity value in the range of 00 to 4. Suitable quartz frits are commercially available from Heraeus Amersil Inc.
- the quartz frits may be sintered to the quartz housing.
- the frits are fused to the interior bore of the housing, with a space there between within which quartz or ceramic beads are packed.
- the bead plug is thus effectively integrated with the quartz housing.
- the method of operation according to the present invention is generally as follows (with reference to FIG. 2).
- a fluid for example, air containing suspended particulate matter is drawn (with a suitable pump or other flow creating device) through the tube 10 , with the particulate matter being retained on the quartz of beads.
- the flow is shut off.
- the tube and filter member now containing the sample is connected to an analyzer 22 and is then heated to thermally desorb the material collected on the quartz or ceramic filter media.
- the species released are then passed through the analyzer 22 for the purpose of qualitative and/or quantitative chemical analysis.
- FIG. 3 illustrates a system for collecting particulate matter suspended in a fluid medium.
- Ambient air as an example, is drawn through the filter device, the flow being produced by a pump 30 and passed through a flow meter/controller 32 to measure/regulate the flow rate of the fluid medium.
- the filter device After collection, the filter device is connected (in reverse) to an analytical system, as shown in FIG. 4.
- the filter device including the collected sample, has a carrier gas supply, for example from a cylinder 36 through a detection device 38 .
- Any suitable detector may be employed for quantifying and/or identifying the species to be analyzed.
- a detector for mercury can be a commercially available cold vapor atomic fluorescence spectrometer (CVAFS).
- a heater 40 surrounds the filter device. The heater is controlled by a variable transformer (Variac) 42 .
- a suitable carrier gas for mercury is, for example, argon, and a suitable detector would be a conventional CVAFS tuned to 253.7 nm in the case of mercury. On heating, the sample on the filter device will be thermally released and detected.
- FIGS. 3 and 4 can be combined, as shown in FIG. 5. Air is drawn through the filter device and the flow meters of 44 via a pump 46 . Particulate matter is collected or retained on the filter member. After collection of a sample, the valve 52 is actuated to close off direct connection to the flow meter, and thus permit flow through the detector 48 and flow restrictor 50 . Carrier gas is supplied from a gas cylinder or other source, at inlet 54 . The filter device is heated by heater 40 and the released species are detected/determined by the detector 48 . Such a system as illustrated in FIG. 5 can be operated manually or automatically.
- the apparatus described herein can be used for sampling and analysis of not only particulate-phase mercury but also any thermally-labile particulate species (chemical substance/element or compound) that can be thermally desorbed at, or below, a temperature of 1200° C. Typical of such species are those identified above.
- a suitable commercial mercury analyzer can be used for fully automated monitoring of mercury associated with airborne particulate matter.
- any suitable commercial carbon (or multi-element) analyzer can be used for determination of the total carbon (as well as other elemental or molecular species) associated with airborne particulate matter.
- any commercial detector with proper interfacing can be used for determination of thermally-labile species associated with particulate matter in ambient air.
- the invention provides for both sampling and analysis of thermally-labile species associated with airborne particulate matter (i.e., the sample) without direct handling, transfer and preparation of the sample.
- the actual filtering device that is the tube with the filter member supported by quarts frits, is entirely reusable. This makes possible the automated monitoring of mercury and other thermally-labile species associated with airborne particulate matter, for example, by connecting the apparatus of the present invention as a front-end device on a TEKRAN® automated mercury analyzer.
- quartz or ceramic beads and frits of this invention instead of conventional filter packs and quartz wool plugs according to the prior art, thus provides numerous distinct and significant advantages including the fact that the device is entirely reusable, easily cleaned, and sampling and analysis procedures are less time-consuming as well as being less costly. Automation (of sampling and/or analysis) is also possible and the sample collection apparatus is chemically inert and can withstand high temperatures.
- the sampling apparatus of this invention has an all quartz construction and no corrosive parts or components, thus making it chemically inert. It is, therefore, resistant to organic or inorganic acids and many other normally reactive chemicals. It is thus also suitable for filtration of corrosive gases and liquids containing suspended solids.
- the apparatus of the present invention is quickly assembled and easily decontaminated by thermal means and other types of treatment, thus avoiding the use of toxic or environmentally unfriendly cleaning agents/reagents/hazardous solutions or the like.
- the method and apparatus of the present invention can achieve ultra-trace analytical detection limits and extremely low (sub-ppt) operational analytical blanks.
- the sampling device is suitable for high temperature applications and the quartz tube 10 is of a transparent nature, allowing easy visual inspection and direct observation of the sample at all stages.
- the beads (uniform in diameter) give a precise pore size distribution and function as a good heat diffuser by having a large surface area conducive to heat distribution.
- the present invention overcomes the disadvantages of the generally known existing techniques (a) filter packs, (b) quartz wool plugs and (c) fiber discs or mats.
- Filter packs generally contain one or more membrane filter(s) of 47 mm diameter or larger, which are precleaned using acid solutions, or heating, depending upon the filter medium. The filters are then manually loaded into the filter holder. After sampling, the sample collected on the filter medium (e.g.
- cellulose (filter paper), polyethylene, “Teflon”, glass fiber or quartz fiber) is transferred, along with the filter, into either a container where it is extracted or digested using acids or mixtures of activation reagents (with or without ultrasonication) followed by analysis, or alternatively a chamber for thermal desorption, followed by identification and quantification.
- activation reagents with or without ultrasonication
- a chamber for thermal desorption followed by identification and quantification.
- the particulate matter is retained (at an unknown collection efficiency) by the quartz wool plug and then the apparatus is heated to a high temperature, the released elements detected and quantified. It is very difficult, if not impossible, to prepare wool plugs uniformly and thus collection efficiency can vary from plug to plug. Absorption of gaseous forms of the element(s) of interest (e.g. Hg° vapor in the case of determining particulate—phase mercury) by the quartz wool during the sample collection step can generate erroneously high results.
- gaseous forms of the element(s) of interest e.g. Hg° vapor in the case of determining particulate—phase mercury
- the invention provides for a reusable member, having a consistent bead size for consistent trapping. It is not detrimentally affected by heat or by other extraction/desorption steps, for example, such as corrosive acids or other hazardous reagents.
- the bead size can be optimized for any particulate material to be collected. The easy and effective cleaning feature and reusability provide for an economical system capable of complete automation.
- the present invention when using quartz beads, provides the flexibility to adjust bead size to suit the particulate matter to be collected, thus ensuring high efficiency of retention during the sampling step.
Abstract
An apparatus for, and a method of, sampling and analyzing thermally-labile chemical species, comprises a quartz tube having a filter member positioned in the bore of the tube. The filter member comprises a plug of quartz beads having a layer of quartz frits on either side. A fluid (gas or liquid) carrying one or more chemical substances associated with particulate matter is passed through the tube, the particulate material being collected by the quartz beads. After sample collection, the material remaining/retained from the original sample is removed, as for example by thermal desorption, and the material is then analyzed.
Description
- This application is a divisional application of U.S. patent application Ser. No. 09/538,136 filed on Mar. 29, 2000.
- This invention relates to an apparatus for sampling and analysis of thermally-labile species, such as mercury, arsenic, selenium, sulfur, lead, carbon, polyaromatic hydrocarbons, n-alkanes and the like, as may be associated with a variety of solid matrices (e.g., airborne particulate matter, suspended particles, soil materials, colloids). The invention also relates to a method of carrying out such sampling and analysis.
- Various technologies exist for either collecting or separating particulate material from a fluid flow such as a gaseous stream. Such devices include filter packs which collect the material(s) of interest and the filter(s) then being treated as, for example, by using one or more acids or oxidation reagents, with the resulting final solution then being analyzed. In another example, a quartz wool stationary phase is used to retain particulate material on a manually-loaded plug contained in a quartz tube. The tube, along with the collected sample, are heated to an elevated temperature and the released elements of interest are detected and quantified. Yet another example is a miniaturized device using a quartz fiber filter disc. Particulate material, suspended in one or more gases or liquids, is trapped on the filter disc, following which the device is heated and the released elements detected and quantified.
- When using filter packs, “clean hands” techniques and a clean-room facility are necessary for accurate results. Furthermore, ultra pure reagents, which are expensive, are required in those procedures involving sample treatment prior to analysis. This mode of operation is, therefore, time consuming and costly. Quartz wool plugs are difficult, if not impossible, to prepare uniformly. Hence, collection efficiency may vary from plug to plug. More importantly, sorption of gaseous species, for example elemental mercury vapor by the quartz wool, may generate erroneously high results in the determination of “particulate-phase mercury” in air. Miniaturized devices with a quartz fiber disc overcome the disadvantages of quartz wool plugs, but the filter disc becomes brittle after being heated at a high temperature, for example over 900° C. A fresh filter disc is therefore required for each sample. Hence it is difficult to automate the whole measurement procedure, including sampling and sample analysis.
- With prior art technologies, e.g. quartz wool plugs, it is a major problem to collect particles of sub-micron size in such a way that uniform and consistent sampling is obtained. It is a further problem to provide an efficient automated and economical procedure.
- The present invention provides a novel apparatus, and a method, which is efficient, economical and which can be easily automated. In accordance with the present invention, there is provided a device for trapping particulate material in a fluid (usually/generally gaseous) stream, such as ambient air, or other fluid media, together with a pyrolyzer for sample pre-treatment prior to analysis. Thus, the present invention is suitable for sampling and analyzing mercury, for example, as well as other thermally-labile species. Broadly, a device of the present invention comprises a quartz housing with a filter member having a quartz bead plug and bead retainers such as quartz frits positioned on either side of the quartz beads. The housing, preferably in the form of a tube, is variable in length and in width. The porosity of the bead plugs may vary, as desired, depending on the size range of the particulate matter to be collected. The dimensions of the plug can vary as can the pore size of the quartz frits.
- In the method in accordance with the inventions, a filter member comprising a quartz bead plug having quartz frits on either side thereof is loaded into a quartz housing e.g. a tube. A flow of fluid gas, for example air containing airborne particulate material, is passed through the tube with particulate material being collected in the quartz bead plug. After passage of the fluid, the whole unit may be positioned in a heating chamber where the tube and filter member are heated to a high temperature, for example up to 900° C. or up to 1200° C., for thermal desorption and subsequent analysis of the collected material by an analyzer located downstream of the sampling unit.
- The invention will be readily understood by the following description of certain embodiments, by way of example, in conjunction with the accompanying drawings in which:
- FIG. 1 diagrammatically illustrates one form of a device;
- FIG. 2 is a diagrammatic illustration of a system embodying a device as in FIG. 1; and
- FIGS. 3, 4 and5 illustrate diagrammatically slightly different systems as further examples. Common reference numerals are used where applicable.
- As shown in FIG. 1, an apparatus comprises a
quartz tube 10, having aninlet 12 and anoutlet 14. Centrally positioned in thetube 10 is a filter member or element designated generally as 16, having acentral plug 18 of quartz beads with a layer quartz frit 20 on each side. Thus, fluid flow enters atinlet 12 as indicated, exiting at 14. During passage through themember 16, particulate material in the gas (or liquid) is retained on the quartz beads. After a predetermined volume of fluid flows through thefilter member 16, the flow is cut off. Thetube 10 and containedmember 16 is then heated to, to a selected temperature for example, 1200° C. The chemical species of interest, which are associated with the particulate material on the beads, are thermally desorbed (either slowly or rapidly depending upon the rate of heating of the apparatus). - The
tube 10 is normally connected to ananalyzer 22 and the tube itself can be positioned in a heating enclosure, for example, a suitable housing as indicated at 24, for the heating thereof. To this end, any suitable heating device may be employed; preferably, the means of heating is a heater which surrounds the quartz housing or tube and may be in the form of heating wires, an infrared heating device, or a suitable microwave oven or cavity. - The diameter and length of the
tube 10 will vary depending upon the specific application. The larger the tube, the higher the flow rate, but too large a tube can result in insufficient heating, particularly at the center of thefilter member 16, as well as reducing the rate at which the tube is heated. In one example, the tube has a bore of between 10 and 20 mm., with thefilter member 16 having a length of about 2 mm. - As noted above, the size of the quartz beads can vary depending upon the specific application. As a general rule, the smaller the particle size of the particulate matter to be collected, the smaller the size of the beads. The length of the
quartz bead plug 18 should be long enough to retain all particulate material in the desired size range. Typically, theparticulate filtration medium 18 may be in the form of quartz or ceramic beads which have a size of from about 8 to about 170 mesh, and more desirably from about 40 mesh to about 120; or between 80 and 170 mesh. - Also, the porosity of the quartz frits can vary depending upon the specific application. As a general rule, the pore size of the
quartz frits 20 should be smaller than the size of thequartz beads 18. Typically, the porosity of the quartz frits will vary from a porosity value in the range of 00 to 4. Suitable quartz frits are commercially available from Heraeus Amersil Inc. - In a preferred embodiment of the invention, where the quartz frits are in a quartz housing, the quartz frits may be sintered to the quartz housing. The frits are fused to the interior bore of the housing, with a space there between within which quartz or ceramic beads are packed. The bead plug is thus effectively integrated with the quartz housing.
- The method of operation according to the present invention is generally as follows (with reference to FIG. 2). A fluid, for example, air containing suspended particulate matter is drawn (with a suitable pump or other flow creating device) through the
tube 10, with the particulate matter being retained on the quartz of beads. After a predetermined volume of air, or other fluid medium, has been sampled, the flow is shut off. The tube and filter member now containing the sample, is connected to ananalyzer 22 and is then heated to thermally desorb the material collected on the quartz or ceramic filter media. The species released are then passed through theanalyzer 22 for the purpose of qualitative and/or quantitative chemical analysis. - FIG. 3 illustrates a system for collecting particulate matter suspended in a fluid medium. Ambient air, as an example, is drawn through the filter device, the flow being produced by a
pump 30 and passed through a flow meter/controller 32 to measure/regulate the flow rate of the fluid medium. - After collection, the filter device is connected (in reverse) to an analytical system, as shown in FIG. 4. The filter device, including the collected sample, has a carrier gas supply, for example from a
cylinder 36 through adetection device 38. Any suitable detector may be employed for quantifying and/or identifying the species to be analyzed. For example, a detector for mercury can be a commercially available cold vapor atomic fluorescence spectrometer (CVAFS). Aheater 40 surrounds the filter device. The heater is controlled by a variable transformer (Variac) 42. A suitable carrier gas for mercury is, for example, argon, and a suitable detector would be a conventional CVAFS tuned to 253.7 nm in the case of mercury. On heating, the sample on the filter device will be thermally released and detected. - In a manual approach for the determination of particulate-phase mercury in ambient air, airborne particulate matter is collected on the precleaned quartz medium at a flow rate ranging from 3 to 5 L/min. After twelve hours of sampling, the device, along with the sample, is connected to an analytical train, similar to that shown in FIG. 4. The device is then heated to 900° C. for 5 minutes and the released mercury species are carried downstream by argon gas at a flow rate of 200 ml per min. to a TEKRAN® mercury vapor analyzer, where the mercury (and/or other constituents) in the sample is/are quantified.
- The systems of FIGS. 3 and 4 can be combined, as shown in FIG. 5. Air is drawn through the filter device and the flow meters of44 via a
pump 46. Particulate matter is collected or retained on the filter member. After collection of a sample, thevalve 52 is actuated to close off direct connection to the flow meter, and thus permit flow through thedetector 48 and flowrestrictor 50. Carrier gas is supplied from a gas cylinder or other source, atinlet 54. The filter device is heated byheater 40 and the released species are detected/determined by thedetector 48. Such a system as illustrated in FIG. 5 can be operated manually or automatically. - The apparatus described herein can be used for sampling and analysis of not only particulate-phase mercury but also any thermally-labile particulate species (chemical substance/element or compound) that can be thermally desorbed at, or below, a temperature of 1200° C. Typical of such species are those identified above.
- For example, a suitable commercial mercury analyzer can be used for fully automated monitoring of mercury associated with airborne particulate matter. Likewise, any suitable commercial carbon (or multi-element) analyzer can be used for determination of the total carbon (as well as other elemental or molecular species) associated with airborne particulate matter. Similarly, any commercial detector with proper interfacing can be used for determination of thermally-labile species associated with particulate matter in ambient air.
- The invention provides for both sampling and analysis of thermally-labile species associated with airborne particulate matter (i.e., the sample) without direct handling, transfer and preparation of the sample. The actual filtering device, that is the tube with the filter member supported by quarts frits, is entirely reusable. This makes possible the automated monitoring of mercury and other thermally-labile species associated with airborne particulate matter, for example, by connecting the apparatus of the present invention as a front-end device on a TEKRAN® automated mercury analyzer.
- The use of quartz or ceramic beads and frits of this invention, instead of conventional filter packs and quartz wool plugs according to the prior art, thus provides numerous distinct and significant advantages including the fact that the device is entirely reusable, easily cleaned, and sampling and analysis procedures are less time-consuming as well as being less costly. Automation (of sampling and/or analysis) is also possible and the sample collection apparatus is chemically inert and can withstand high temperatures.
- The sampling apparatus of this invention has an all quartz construction and no corrosive parts or components, thus making it chemically inert. It is, therefore, resistant to organic or inorganic acids and many other normally reactive chemicals. It is thus also suitable for filtration of corrosive gases and liquids containing suspended solids.
- The apparatus of the present invention is quickly assembled and easily decontaminated by thermal means and other types of treatment, thus avoiding the use of toxic or environmentally unfriendly cleaning agents/reagents/hazardous solutions or the like. Thus, the method and apparatus of the present invention can achieve ultra-trace analytical detection limits and extremely low (sub-ppt) operational analytical blanks. Furthermore, the sampling device is suitable for high temperature applications and the
quartz tube 10 is of a transparent nature, allowing easy visual inspection and direct observation of the sample at all stages. The beads (uniform in diameter) give a precise pore size distribution and function as a good heat diffuser by having a large surface area conducive to heat distribution. - The present invention overcomes the disadvantages of the generally known existing techniques (a) filter packs, (b) quartz wool plugs and (c) fiber discs or mats. Filter packs generally contain one or more membrane filter(s) of 47 mm diameter or larger, which are precleaned using acid solutions, or heating, depending upon the filter medium. The filters are then manually loaded into the filter holder. After sampling, the sample collected on the filter medium (e.g. cellulose (filter paper), polyethylene, “Teflon”, glass fiber or quartz fiber) is transferred, along with the filter, into either a container where it is extracted or digested using acids or mixtures of activation reagents (with or without ultrasonication) followed by analysis, or alternatively a chamber for thermal desorption, followed by identification and quantification. For accurate results, when using a conventional or traditional trace or ultra-trace measurement procedure, a “clean hands” technique and a clean-room facility are essential. Ultra-pure reagents, a necessity for traditional approaches are costly. The conventional procedure is time consuming and expensive to operate.
- For quartz wool plugs, the particulate matter is retained (at an unknown collection efficiency) by the quartz wool plug and then the apparatus is heated to a high temperature, the released elements detected and quantified. It is very difficult, if not impossible, to prepare wool plugs uniformly and thus collection efficiency can vary from plug to plug. Absorption of gaseous forms of the element(s) of interest (e.g. Hg° vapor in the case of determining particulate—phase mercury) by the quartz wool during the sample collection step can generate erroneously high results.
- Other devices, such as those employing a quartz fiber disc, trap particulate material on the disc. The disc, with collected sample, is heated to a high temperature and released elements detected and quantified. Although overcoming the disadvantages of quartz wool plugs, the quartz fiber filter disc will become brittle after heating and therefore a fresh disc is required for each sample, making it difficult to automate the whole procedure.
- Thus the invention provides for a reusable member, having a consistent bead size for consistent trapping. It is not detrimentally affected by heat or by other extraction/desorption steps, for example, such as corrosive acids or other hazardous reagents. The bead size can be optimized for any particulate material to be collected. The easy and effective cleaning feature and reusability provide for an economical system capable of complete automation.
- The present invention, when using quartz beads, provides the flexibility to adjust bead size to suit the particulate matter to be collected, thus ensuring high efficiency of retention during the sampling step.
Claims (14)
1. Apparatus for sampling and analysis of thermally-labile species, comprising:
a quartz housing having a central passage, and a filter member positioned in said passage; said filter member comprising a particulate filtration medium and retainers associated with said particulate filtration medium through which a fluid flow is adapted to pass.
2. Apparatus as claimed in claim 1 , wherein said particulate filtration medium comprises quartz or ceramic beads.
3. Apparatus as claimed in claim 1 , said retainers each comprising fused quartz frit.
4. Apparatus as claimed in claim 1 , said quartz housing comprising a tube having an inlet end and an outlet end, said outlet end being connected to a single or multi-element analyzer.
5. Apparatus as claimed in claim 4 , said analyzer comprising a multi-element analyzer.
6. Apparatus as claimed in claim 4 , wherein said quartz tube being positioned in a heating enclosure.
7. Apparatus as claimed in claim 4 , wherein said quartz housing includes said filter member positioned to receive a fluid flow through said housing, said retainers forming a layer on both sides of said filter member.
8. Apparatus as claimed in claim 4 , wherein said quartz housing includes said filter member positioned to receive a gaseous flow through said housing, said retainers forming a layer on both sides of said filter member.
9. Apparatus as claimed in claim 2 , said beads having a size of about 8 to about 170 mesh.
10. Apparatus as claimed in claim 9 , said beads having a size of about 40 to about 120 mesh.
11. Apparatus as claimed in claim 2 , said beads having a size of about 80 to about 170 mesh.
12. Apparatus as claimed in claim 3 , said fused quartz frit having a porosity of from 00 to 4.
13. Apparatus as claimed in claim 2 , said tube having a bore of about 10 mm to about 20 mm at said filter member.
14. Apparatus as claimed in claim 13 , said filter member having a length of about 2 mm.
Priority Applications (1)
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US10/232,368 US20030000318A1 (en) | 2000-03-29 | 2002-09-03 | Apparatus for sampling & analysis of thermally-labile species and a method relating thereto |
Applications Claiming Priority (2)
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US09/538,136 US6520033B1 (en) | 2000-03-29 | 2000-03-29 | Apparatus for sampling & analysis of thermally-labile species and a method relating thereto |
US10/232,368 US20030000318A1 (en) | 2000-03-29 | 2002-09-03 | Apparatus for sampling & analysis of thermally-labile species and a method relating thereto |
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US09/538,136 Division US6520033B1 (en) | 2000-03-29 | 2000-03-29 | Apparatus for sampling & analysis of thermally-labile species and a method relating thereto |
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US20030000318A1 true US20030000318A1 (en) | 2003-01-02 |
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US09/538,136 Expired - Fee Related US6520033B1 (en) | 2000-03-29 | 2000-03-29 | Apparatus for sampling & analysis of thermally-labile species and a method relating thereto |
US10/232,368 Abandoned US20030000318A1 (en) | 2000-03-29 | 2002-09-03 | Apparatus for sampling & analysis of thermally-labile species and a method relating thereto |
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US09/538,136 Expired - Fee Related US6520033B1 (en) | 2000-03-29 | 2000-03-29 | Apparatus for sampling & analysis of thermally-labile species and a method relating thereto |
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CA (1) | CA2342126A1 (en) |
Cited By (6)
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US20060225522A1 (en) * | 2005-03-29 | 2006-10-12 | Lockheed Martin Corporation | Method and apparatus for sampling biological particles in an air flow |
US20070167029A1 (en) * | 2005-11-11 | 2007-07-19 | Kowalski Jeffrey M | Thermal processing system, components, and methods |
EP2357461A1 (en) * | 2010-02-17 | 2011-08-17 | MWT Mikrowellen Labor Technik AG | Container with a carrier material element for holding a component of a sample |
US20150206726A1 (en) * | 2009-08-19 | 2015-07-23 | Parisa A. Ariya | Method and system for the quantitative chemical speciation of heavy metals and other toxic pollutants |
CN111397977A (en) * | 2020-05-08 | 2020-07-10 | 西安热工研究院有限公司 | System and method for sampling and testing selenium and selenium compounds in waste gas of fixed pollution source |
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JP4301676B2 (en) * | 2000-02-09 | 2009-07-22 | 日本インスツルメンツ株式会社 | Method and apparatus for measuring mercury in hydrocarbons |
JP2004354067A (en) * | 2003-05-27 | 2004-12-16 | Central Res Inst Of Electric Power Ind | Method for measuring mercury in gas and measuring instrument therefor |
EP1664726A4 (en) * | 2003-09-22 | 2012-05-09 | Tekran Instr Corp | Conditioning system and method for use in the measurement of mercury in gaseous emissions |
US7799113B2 (en) * | 2004-09-02 | 2010-09-21 | Tekran Instruments Corporation | Conditioning system and method for use in the measurement of mercury in gaseous emissions |
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US3667688A (en) * | 1968-06-28 | 1972-06-06 | Huber Corp J M | Method for shearing solids in a solids-liquid suspension |
US3933431A (en) * | 1974-07-23 | 1976-01-20 | The United States Of America As Represented By The United States Energy Research And Development Administration | Method and apparatus for sampling atmospheric mercury |
DE3221570A1 (en) * | 1982-06-08 | 1983-12-08 | Willi Dr. 5483 Bad Neuenahr Jung | Double filtration system |
US4759210A (en) * | 1986-06-06 | 1988-07-26 | Microsensor Systems, Inc. | Apparatus for gas-monitoring and method of conducting same |
US4977095A (en) * | 1986-08-04 | 1990-12-11 | The United States Of America As Represented By The United States Department Of Energy | Liquid-absorption preconcentrator sampling instrument |
EP0309007B1 (en) * | 1988-05-19 | 1991-05-22 | Euroglas B.V. | Method for separating an aqueous liquid and active carbon including adsorbed material |
DE4205792C2 (en) * | 1992-02-26 | 1995-11-02 | Gfa Ges Fuer Arbeitsplatz Und | Method and device for sampling from exhaust gases |
NO933291L (en) * | 1992-09-18 | 1994-03-21 | Halliburton Co | The core stabilization |
AU3974293A (en) * | 1993-04-06 | 1994-10-24 | E.I. Du Pont De Nemours And Company | Separation of chloropentafluoroethane from pentafluoroethane |
EP0665054A1 (en) * | 1994-01-27 | 1995-08-02 | SECURETEC GmbH | Sorbent material for enrichment and recovery of trace element in gaseous phase |
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US5599764A (en) * | 1994-04-29 | 1997-02-04 | California Institute Of Technology | Size selective hydrophobic adsorbent for organic molecules |
JP3992114B2 (en) * | 1997-06-12 | 2007-10-17 | バイオセンサー、アプリケーションズ、スエーデン、アクチボラグ | Apparatus, system and method for detection of analytes in air |
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2000
- 2000-03-29 US US09/538,136 patent/US6520033B1/en not_active Expired - Fee Related
-
2001
- 2001-03-27 CA CA002342126A patent/CA2342126A1/en not_active Abandoned
-
2002
- 2002-09-03 US US10/232,368 patent/US20030000318A1/en not_active Abandoned
Cited By (8)
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US20060225522A1 (en) * | 2005-03-29 | 2006-10-12 | Lockheed Martin Corporation | Method and apparatus for sampling biological particles in an air flow |
US7293473B2 (en) | 2005-03-29 | 2007-11-13 | Lockheed Martin Corporation | Method and apparatus for sampling biological particles in an air flow |
US20070167029A1 (en) * | 2005-11-11 | 2007-07-19 | Kowalski Jeffrey M | Thermal processing system, components, and methods |
US20150206726A1 (en) * | 2009-08-19 | 2015-07-23 | Parisa A. Ariya | Method and system for the quantitative chemical speciation of heavy metals and other toxic pollutants |
US9627188B2 (en) * | 2009-08-19 | 2017-04-18 | Mcgill University | Method and system for the quantitative chemical speciation of heavy metals and other toxic pollutants |
EP2357461A1 (en) * | 2010-02-17 | 2011-08-17 | MWT Mikrowellen Labor Technik AG | Container with a carrier material element for holding a component of a sample |
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Also Published As
Publication number | Publication date |
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US6520033B1 (en) | 2003-02-18 |
CA2342126A1 (en) | 2001-09-29 |
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