1、Designation: D7144 05a (Reapproved 2016)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. No other units of measurement are included in thisstandard
5、.1.5 LimitationsDue to a number of physical factors inher-ent 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 towardss
6、maller, less dense dust particles. Nevertheless, the use of 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 co
7、ncerns, if any, associated with its use. It is theresponsibility 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 Samplin
8、g and Analysis ofAtmospheresD3195 Practice for Rotameter CalibrationD4840 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 Meta
9、ls2.2 ISO Standard:4ISO 15202-1 Workplace airDetermination of 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, r
10、efer to TerminologyD1356.3.2 Definitions of Terms Specific to This Standard: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. D13563.2.2 batch
11、a group of field or quality control samples, orboth, that are collected together in a similar environment andare processed together using the same reagents and equipment.3.2.3 collection nozzlea piece of flexible plastic tubing cutat a 45 angle at the inlet end, and connected at the outlet endto the
12、 inlet orifice of a filter holder (sampling cassette).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 Oct. 1, 2016. Published October 2016. Originallyapproved in 200
13、5. Last previous edition approved in 2011 as D7144 05a (2011).DOI: 10.1520/D7144-05AR16.2Reynolds, S. J., et al.,“Laboratory Comparison of Vacuum, OSHA, and HUDSampling Methods for Lead in Household Dust,” American Industrial HygieneAssociation Journal, Vol. 58, 1997, pp. 439446.3For referenced ASTM
14、 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 Standards Institute (ANSI), 25 W. 43rd St.,4th
15、Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4 field blanka sample that is handled in exactly thesame way that field samples are collected, except that no air isdrawn through it.3.2
16、.5 filter holderan apparatus that supports and containsthe filter medium 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 a
17、nd prevents deposition of collectedmaterial on the internal walls of the sampling cassette. Use ofan internal capsule is necessary for gravimetric analysispurposes.3.2.6.1 DiscussionSuch capsules are commercially avail-able.3.2.7 sampling device (assembly)for micro-vacuumsampling, an apparatus consi
18、sting of the collection nozzle,filter holder (containing internal capsule, if necessary), 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 samplin
19、g pump. The filter holder is attached to the pump byflexible tubing.3.2.8 surface 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 d
20、ust are collected from selectedsampling locations into individual filter holders by 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
21、may include particles which ad-here to the internal walls of the filter holder. This 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 accura
22、tely weighed is used duringsample collection.5. Significance and Use5.1 Human exposure 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, st
23、andardizedmethods for the collection and analysis of metals in surfacedust samples 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 f
24、or use by qualified technical professionals.5.3 This practice allows for the subsequent 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 l
25、ength of thecollection nozzle is specified in order that such losses arecomparable 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
26、roughened wood; (c) confined areas that cannot be easilysampled by other means (such 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
27、technique that may be used for samplingcarpets is described in Practice D5438.5.6 Procedures 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). Addition
28、ally, theprocedure described uses equipment that is readily availableand in common 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
29、 internal capsule is used if gravimetricanalysis is necessary.6. Apparatus6.1 Dust Sampling EquipmentThe sampling assembly(see Fig. 1) for the micro-vacuum collection of surface dustsamples has the following components:6.1.1 Filters, of a diameter suitable for use with the filterholders, and with a
30、collection efficiency of not less than 99.5 %for particles with a diffusion diameter 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 d
31、etermine the mass of collected dust.5Que 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, 1985, pp. 7795.A: Flexible tubing connecting the filter holder to the sampling pump (not sh
32、own);B: Outlet of filter holder;C: Back-up pad/support;D: Filter;E: Inlet of filter holder;F: Housing of filter holder;G: Flexible tubing collection nozzle.FIG. 1 Schematic of Sampling Assembly for Micro-Vacuum Sur-face Dust SamplingD7144 05a (2016)2NOTE 1If the filters are to be weighed in order to
33、 determine the massof dust collected, it is important that they be resistant to 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-sivel
34、y brittle, since this can introduce weighing errors due to loss of filtermaterial.6.1.2 Filter holders, for 25- or 37-mm diameter filters.6.1.3 Internal capsules, for gravimetric analysisIf it isdesired to determine the mass of collected dust, internalcapsules shall be weighed to the nearest 0.1 mg.
35、NOTE 2If pre-weighed internal capsules and filters are used, it will benecessary to 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.NOT
36、E 3If pre-weighed filters are used, it is not necessary to know themass of each back-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
37、 nearest 0.1 mg).6.1.5 Collection nozzle, consisting of a piece of flexiblepolyvinyl 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
38、 sampling pump(maximum length 1 m).6.1.7 Air sampling pump, portable, capable of sampling 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 d
39、evice, for air sampling pumps; soapbubble meter or equivalent, as specified in Practice 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
40、 or cardboard.6.1.11 Gloves, powderless, latex-free, for handling of filters,back-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 oftemp
41、lates is impractical.6.1.13 Tape measure or ruler, metric, for measurement ofsampling 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 b
42、ags, or boxes, or other airtightcontainers, or a combination of the three, for transportingcollected 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,
43、 with the filtersupported on a back-up pad or metallic screen. To preventcontamination, 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 4If desired, pre-lo
44、aded filter holders and capsules with pre-weighed filters and internal capsules may be purchased, alreadyassembled, 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
45、.1.4 Attach the outlet end of the collection nozzle to theinlet end of the filter 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 equi
46、valent calibrationdevice (for example, a calibrated rotameter; see PracticeD3195), set the flow rate of the air sampling pump, with asampling assembly in the line, to 2.5 6 0.1 L/min.NOTE 5While soap bubble meters are useful for applications in thelaboratory and in the field, calibrated rotameters a
47、re especially convenientfor on-site calibrations and calibration checks.7.2.3 Calibration 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, theass
48、embly with the collection nozzle attached to filter holder) tothe calibrated sampling pump by means of a piece of flexibletubing.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
49、example, 10 cm by 10 cm) using a template, andsecure the outside edges of the template 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 6Areas 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 sampl
