1、Designation: D7144 05a (Reapproved 2011)Standard Practice forCollection of Surface Dust by Micro-vacuum Sampling forSubsequent Metals Determination1This standard is issued under the fixed designation D7144; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the micro-vacuum collection ofsurface dust for subsequent det
3、ermination of metals. Theprimary intended application is for sampling from soft, rough,or porous surfaces.1.2 Micro-vacuum sampling is carried out using a collectionnozzle attached to a filter holder (sampling cassette) that isconnected to an air sampling pump.1.3 This practice allows for the subseq
4、uent determination ofmetals on a loading basis (mass of metal(s) per unit areasampled), or on a concentration basis (mass of metal(s) per unitmass of sample collected), or both.1.4 The values stated in SI units are to be regarded asstandard.1.5 LimitationsDue to a number of physical factors inher-en
5、t in the micro-vacuum sampling method, analytical resultsfor vacuum dust samples are not likely to reflect the total dustcontained within the sampling area prior to sample collection.Indeed, dust collection will generally be biased towardssmaller, less dense dust particles. Nevertheless, the use of
6、thisstandard practice will generate data that are consistent andcomparable between operators performing micro-vacuum col-lection at a variety of sampling locations and sites.21.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibi
7、lity of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1356 Terminology Relating to Sampling and Analysis ofAtmospheresD3195 Practice for Rotameter Cal
8、ibrationD4840 Guide for Sample Chain-of-Custody ProceduresD5438 Practice for Collection of Floor Dust for ChemicalAnalysisD6966 Practice for Collection of Settled Dust SamplesUsing Wipe Sampling Methods for Subsequent Determi-nation of Metals2.2 ISO Standard:4ISO 15202-1 Workplace airDetermination o
9、f metals andmetalloids in airborne particulate matter by inductivelycoupled plasma atomic emission spectrometryPart 1:Sampling3. Terminology3.1 DefinitionsFor definitions of terms relating to sam-pling and analysis of dust not given here, refer to D1356.3.2 Definitions of Terms Specific to This Stan
10、dard:3.2.1 air sampling pumpa portable pump that is used todraw air through a filter holder/collection nozzle assembly formicro-vacuum collection of surface dust. An example wouldinclude a personal sampling pump (D1356).3.2.2 batcha group of field or quality control samples, orboth, that are collect
11、ed together in a similar environment andare processed together using the same reagents and equipment.1This practice is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.Current edition approved March 1, 2011. P
12、ublished March 2011. Originallyapproved in 2005. Last previous edition approved in 2005 as D7144 - 05a. DOI:10.1520/D7144-05AR11.2Reynolds, S. J., et al., “Laboratory comparison of vacuum, OSHA, and HUDsampling methods for lead in household dust.” American Industrial HygieneAssociation Journal, Vol.
13、 58, pp. 439-446 (1997).3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American National Sta
14、ndards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 collection nozzlea piece of flexible plastic tubingcut at a 45 angle at the inlet end, an
15、d connected at the outletend to the inlet orifice of a filter holder (sampling cassette).3.2.4 field blanka sample that is handled in exactly thesame way that field samples are collected, except that no air isdrawn through it.3.2.5 filter holderan apparatus that supports and containsthe filter mediu
16、m upon which dust is collected. It is also oftenreferred to as a sampling cassette.3.2.6 internal capsulea device inserted into a filter holder(sampling cassette) that allows complete capture of contami-nant within its envelope and prevents deposition of collectedmaterial on the internal walls of th
17、e sampling cassette. Use ofan internal capsule is necessary for gravimetric analysispurposes.NOTE 1Such capsules are commercially available.3.2.7 sampling device (assembly)for micro-vacuum sam-pling, an apparatus consisting of the collection nozzle, filterholder (containing internal capsule, if nece
18、ssary), and airsampling pump, used to collect surface dust. The collectionnozzle is attached to the inlet end of the filter holder. The filterholder houses the filter, through which air is drawn by using theair sampling pump. The filter holder is attached to the pump byflexible tubing.3.2.8 surface
19、dustparticulate matter on a given surfacewhich has been transported to its present location by variousmeans, such as settling through the air or tracking from othersources.4. Summary of Practice4.1 Samples of surface dust are collected from selectedsampling locations into individual filter holders b
20、y using amicro-vacuum collection technique that employs a personalsampling pump.5The sample is then processed for transportand subsequent laboratory analysis for determination of metalscontent.4.2 The collected sample may include particles which ad-here to the internal walls of the filter holder. Th
21、is materialshould be rinsed or wiped off and added to the sample meantfor subsequent chemical analysis. However, this materialcannot be included in gravimetric determination unless aninternal capsule that can be accurately weighed is used duringsample collection.5. Significance and Use5.1 Human expo
22、sure to toxic metals present in surface dustcan result from dermal contact with or ingestion of contami-nated dust.Also, inhalation exposure can result from disturbingdust particles from contaminated surfaces. Thus standardizedmethods for the collection and analysis of metals in surfacedust samples
23、are needed in order to evaluate the potential forhuman exposure to toxic elements.5.2 This practice involves the use of sampling equipment tocollect surface dust samples that may contain toxic metals, andis intended for use by qualified technical professionals.5.3 This practice allows for the subseq
24、uent determination ofcollected metals concentrations on an area (loading) or massconcentration basis, or both.5.4 Because particle losses can occur due to collection ofdust onto the inner surfaces of the nozzle, the length of thecollection nozzle is specified in order that such losses arecomparable
25、from one sample to another.5.5 This practice is suitable for the collection of surface dustsamples from, for example: (a) soft, porous surfaces such ascarpet or upholstery; (b) hard, rough surfaces such as concreteor roughened wood; (c) confined areas that cannot be easilysampled by other means (suc
26、h as wipe sampling as describedin Practice D6966). A companion sampling technique that maybe used for collection of surface dust from hard, smoothsurfaces is wipe sampling (Practice D6966). A companionvacuum sampling technique that may be used for samplingcarpets is described in Practice D5438.5.6 P
27、rocedures presented in this practice are intended toprovide a standardized method for dust collection from sur-faces that cannot be reliably sampled using wipe collectionmethods (for example, Practice D6966). Additionally, theprocedure described uses equipment that is readily availableand in common
28、use for other environmental and occupationalhygiene sampling applications.5.7 The entire contents of the filter holder, that is, the filterplus collected dust, is targeted for subsequent analysis formetals content. An internal capsule is used if gravimetricanalysis is necessary.6. Apparatus6.1 Dust
29、sampling equipmentThe sampling assembly (seeFig. 1) for the micro-vacuum collection of surface dust sampleshas the following components:6.1.1 Filters, of a diameter suitable for use with the filterholders, and with a collection efficiency of not less than 99.5 %for particles with a diffusion diamete
30、r of 0.3 m, and with avery low metal content (typically less than 0.1 g of each metalof interest per filter) (see ISO 15202-1).6.1.1.1 Weight-stable filters or matched-weight filters shallbe used if it is desired to determine the mass of collected dust.NOTE 2If the filters are to be weighed in order
31、 to determine the mass5Que Hee, S. S., et al., “Evolution of efficient methods to sample lead sources,such as house dust and hand dust, in the homes of children.” EnvironmentalResearch, Vol. 38, pp. 77-95 (1985).FIG. 1 Schematic of Sampling Assembly for Micro-VacuumSurface Dust SamplingA: Flexible t
32、ubing connecting the filter holder to the samplingpump (not shown); B: Outlet of filter holder; C: Back-up pad/support; D: Filter; E: Inlet of filter holder; F: Housing of filterholder; G: Flexible tubing collection nozzleD7144 05a (2011)2of dust collected, it is important that they be resistant to
33、moistureretention, so that blank weight changes that can occur as a result ofchanges in temperature and humidity are as low and repeatable aspossible. Also, filters selected for weight stability should not be exces-sively brittle, since this can introduce weighing errors due to loss of filtermateria
34、l.6.1.2 Filter holders, for 25- or 37-mm diameter filters.6.1.3 Internal capsules, for gravimetric analysisIfitisdesired to determine the mass of collected dust, internalcapsules shall be weighed to the nearest 0.1 mg.NOTE 3If pre-weighed internal capsules and filters are used, it will benecessary t
35、o tare the internal capsules, plus backup pads, prior to use.Procedures for accurate weighing of internal capsules are described indetail elsewhere.66.1.4 Back-up pads, cellulosic; or metallic screen back-upsupport.NOTE 4If pre-weighed filters are used, it is not necessary to know themass of each ba
36、ck-up pad. However, if pre-weighed internal capsules andpre-weighed filters are used, it will be necessary to know the influence ofthe mass of each back-up pad on the overall mass of the entire samplingassembly (to the nearest 0.1 mg).6.1.5 Collection nozzle, consisting of a piece of flexiblepolyvin
37、yl chloride (PVC) tubing of length 5.5 6 0.5 cm and0.60 6 0.005 cm inside diameter, cut at a 45 angle at the inletend.6.1.6 Tubing, flexible, inside diameter 0.60 6 0.005 cm forconnecting the sampling device to the air sampling pump(maximum length 1 m).6.1.7 Air sampling pump, portable, capable of s
38、ampling at aflow rate of 2.5 6 0.5 L/min. The pump shall be calibratedwith a representative sampling assembly in line so that thevolume of air sampled can be measured to an accuracy of65 % or better.6.1.8 Calibration device, for air sampling pumps; soapbubble meter or equivalent, as specified in Pra
39、ctice D3195.6.1.9 Rotameter, calibrated, as specified in Practice D3195.6.1.10 Sampling templates, minimum dimensions 10 cm by10 cm, maximum dimensions 30 cm by 30 cm; reusablemetallic or plastic; or disposable plastic or cardboard.6.1.11 Gloves, powderless, latex-free, for handling of filters,back-
40、up pads/supports, samplers, tubing, collection nozzles,and other sample collection components.6.1.12 Tape, adhesive, for immobilization of sampling tem-plates; and for delineation of sampling areas where the use oftemplates is impractical.6.1.13 Tape measure or ruler, metric, for measurement ofsampl
41、ing areas when the use of templates is impractical, andfor measurement of tubing, collection nozzles, and so forth.6.1.14 Tweezers, plastic or plastic-tipped metallic, for han-dling of filters.6.1.15 Sealable plastic bags, or boxes, or other airtightcontainers, or a combination of the three, for tra
42、nsportingcollected samples.7. Procedure7.1 Assembly of micro-vacuum sampling deviceThe fol-lowing shall be carried out in an uncontaminated area whilewearing clean gloves:7.1.1 Assemble the filter in the filter holder, with the filtersupported on a back-up pad or metallic screen. To preventcontamina
43、tion, the filter should be handled only with tweezers.7.1.2 If pre-weighed filters and internal capsules are used,record their masses to the nearest 0.1 mg using establishedacceptance criteria.6NOTE 5If desired, pre-loaded filter holders and capsules with pre-weighed filters and internal capsules ma
44、y be purchased, already as-sembled, from the manufacturer.7.1.3 Close and seal the sampling device to prevent leakageof air around the filter or into/out of the sampler. Label thesampler with a unique sample identifier.7.1.4 Attach the outlet end of the collection nozzle to theinlet end of the filte
45、r holder, and secure tightly.7.2 Calibration of sampling train for micro-vacuum sam-pling:7.2.1 Ensure that sampling pumps, if battery-powered, aresufficiently charged prior to use.7.2.2 Using a soap bubble meter or equivalent calibrationdevice (for example, a calibrated rotameter; see PracticeD3195
46、), set the flow rate of the air sampling pump, with asampling assembly in the line, to 2.5 6 0.1 L/min.NOTE 6While soap bubble meters are useful for applications in thelaboratory and in the field, calibrated rotameters are especially convenientfor on-site calibrations and calibration checks.7.2.3 Ca
47、libration of sampling pumps shall be checked priorto and following use.7.3 Preparation for samplingThe following shall be car-ried out while wearing clean gloves:7.3.1 Attach the sample collection device (that is, theassembly with the collection nozzle attached to filter holder) tothe calibrated sam
48、pling pump via a piece of flexible tubing.7.3.2 Using indelible ink, uniquely label the sampling cas-sette of each sample collection assembly.7.3.3 If possible, demarcate the area of the surface to besampled (for example, 10 cm by 10 cm) using a template, andsecure the outside edges of the template
49、with tape. If it is notpractical to use a template, carefully measure the area (in cmby cm) to be sampled using a tape measure or ruler, anddelineate the sampling area with tape.NOTE 7Areas where template-assisted sampling may not be possibleinclude, for example, locations where: (a) the surface to be sampled isconfined or otherwise not easily accessible; (b) the surface to be sampledis smaller (in at least one dimension) than the template; (c) the surface tobe sampled is curved (not flat); and so forth.7.3.4 Activate the sampling pump and allow for a suita
