1、Designation: D 6196 03Standard Practice forSelection of Sorbents, Sampling, and Thermal DesorptionAnalysis Procedures for Volatile Organic Compounds in Air1This standard is issued under the fixed designation D 6196; the number immediately following the designation indicates the year oforiginal adopt
2、ion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice is intended to assist in the selection ofsorbents and proc
3、edures for the sampling and analysis ofambient (1)2, indoor (2) and workplace (3, 4) atmospheres fora variety of common volatile organic compounds (VOCs). Itmay also be used for measuring emissions from materials insmall or full scale environmental chambers or for humanexposure assessment.1.2 A comp
4、lete listing of VOCs for which this practice hasbeen tested, at least over part of the measurement range (1.6),is shown in Tables 1-9. For other compounds this practice shallbe tested according to EN 1076 (pumped); Practice D 6246,ISO 16107, ANSI/ISEA 104, EN 838 or EN 13528-1/EN 13528-2 (diffusive)
5、; or other appropriate validation proto-cols (Sections 13 and 14). (5,1)1.3 This practice is based on the sorption of VOCs from aironto selected sorbents or combinations of sorbents. Sampledair is either drawn through a tube containing one or a series ofsorbents (pumped sampling) or allowed to diffu
6、se, undercontrolled conditions, onto the sorbent tube or tubes (diffusiveor passive sampling). The sorbed VOCs are subsequentlyrecovered by thermal desorption and analyzed by capillary gaschromatography.1.4 This practice applies to three basic types of samplersthat are compatible with thermal desorp
7、tion: (1) pumpedsorbent tubes containing one or more sorbents; (2) axialdiffusive samplers (typically of the same physical dimensionsas standard pumped sorbent tubes and containing only onesorbent); and (3) radial diffusive samplers.1.5 This practice recommends a number of sorbents that canbe packed
8、 in sorbent tubes, for use in the sampling of a widerange of different volatile organic compounds boiling in therange 0 to 400C (v.p. 15 to 0.01 kPa at 25C).1.5.1 For pumped sampling, sorbent selection is based onbreakthrough capacity. Single-bed tubes containing for ex-ample sorbent Type A3,4are ap
9、propriate for normal alkanesfrom n-C6(hexane) to n-C10(decane) and substances withsimilar volatility (v.p. 15 to 0.3 kPa at 25C). More volatilematerials should be sampled on stronger sorbents, such assorbent Type B3,5. Other sorbent types than those specified maybe used, if their breakthrough capaci
10、ties are adequate and theirthermal desorption blanks are sufficiently small. Examples aregiven in Appendix X2. A broader range of VOCs may besampled using multi-bed tubes.1.5.2 Guidance given for the selection of sorbents forpumped monitoring tubes can be applied equally well to axialdiffusive sampl
11、ing tubes. The restriction to a single samplingsurface (hence single sorbent), limits the target analyte rangethat can be monitored by a single tube. However, the unobtru-sive nature and low cost of diffusive samplers usually meansthat two or more samplers containing different sorbents can beused in
12、 parallel without impacting study objectives.1.5.3 The high sampling rate and associated risk of backdiffusion associated with radial diffusive samplers typicallyrestricts the use of these samplers to compounds of equal orlower volatility than benzene. It also means that strongersorbents are general
13、ly required for these samplers whencompared with either axial diffusive or pumped sorbent tubes.1.6 This practice can be used for the measurement ofairborne vapors of these volatile organic compounds over awide concentration range.1.6.1 With pumped sampling, this practice can be used forthe measurem
14、ent of airborne vapors of VOCs in a concentra-tion range of approximately 0.1 g/m3to 1 g/m3, for individualorganic compounds in 110 L air samples. The method is alsosuitable for the measurement of the airborne concentrations of1This practice is under the jurisdiction of ASTM Committee D22 on Samplin
15、gand Analysis of Atmospheres and is the direct responsibility of SubcommitteeD22.05 on Indoor Air.Current edition approved May 10, 2003. Published July 2003. Originallyapproved in 1997. Last previous edition approved in 1997 as D 6196 - 97.2The bold face numbers in parentheses refer to the list of r
16、eferences at the endof this practice.3If you are aware of alternative sorbent types, please provide this information toASTM Headquarters. Your comments will be carefully considered at a meeting ofthe responsible technical committee, which you may attend.4An example of sorbent Type A known to perform
17、 as specified in this practiceis Chromosorb 106 manufactured by Manville Corp., USA and available fromseveral commercial sources.5An example of sorbent Type B known to perform as specified in this practiceis Carboxen 569 manufactured by Supelco, Inc., USA.1Copyright ASTM International, 100 Barr Harb
18、or Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.individual components of volatile organic mixtures, providedthat the total loading of the mixture does not exceed thecapacity of the tube. Quantitative measurements are possiblewhen using validated procedures with appropriate qua
19、lityassurance measures.1.6.2 With axial diffusive sampling, this practice is valid forthe measurement of airborne vapors of volatile organic com-pounds in a concentration range of approximately 2 mg/m3to10 mg/m3for individual organic compounds for an exposuretime of8hor0.3mg/m3to 300 mg/m3for indivi
20、dual organiccompounds for an exposure time of four weeks. The method isalso suitable for the measurement of the airborne concentra-tions of individual components of volatile organic mixturesprovided that the total loading of the mixture does not exceedthe capacity of the tube.1.6.3 With radial diffu
21、sive sampling, this practice is validfor the measurement of airborne vapors of volatile organiccompounds in a concentration range of approximately 0.3mg/m3to 300 mg/m3for individual organic compounds forexposure times of one to six hours. The method is also suitablefor the measurement of the airborn
22、e concentrations of indi-vidual components of volatile organic mixtures provided thatthe total loading of the mixture does not exceed the capacity ofthe tube.1.6.4 The upper limit of the useful range is set by thesorptive capacity of the sorbent used, and by the lineardynamic range of the gas chroma
23、tograph, column and detector,or by the sample splitting capability of the analytical instru-mentation used. The sorptive capacity is measured as abreakthrough volume of air, which determines the maximumair volume that must not be exceeded when sampling with apump.1.6.5 The lower limit of the useful
24、range depends on thenoise level of the detector and on blank levels of analyte orinterfering artifacts, or both, on the sorbent tubes.1.6.6 Artifacts are typically 50C) maximumdesorption temperatures such as sorbent Type A and graphi-tized carbon, must NOT be packed into a single tube or it willbe i
25、mpossible to condition or desorb the more stable sorbent(s)sufficiently thoroughly without causing degradation of the leaststable sorbent(s).7.3 Sorbent tubes for axial diffusive sampling, compatiblewith the thermal desorption apparatus to be used (7.5) and withthe sampling surface of the sorbent re
26、tained by a metal(typically stainless steel) gauze to give a precisely defined airgap (7.3.1). Typically, but not exclusively, they are constructedof stainless steel tubing, 6.4 mm 14 in. OD, 5 mm ID and 89mm long and with the sorbent held in place 14.3 mm from thesampling end using a stainless stee
27、l gauze. (Fig. 1) Tubes ofother dimensions may be used but the uptake rates given inTables 7 and 8 are based on these tube dimensions. For labileanalytes, such as sulfur-containing compounds, fused silica-coated steel should be used for both the tube and sorbent-retaining gauze. One end of the tube
28、is marked, for example bya scored ring about 14 mm from the sampling inlet end. Thetubes are packed with sorbents (8.3) such that the sorbent bedwill be within the desorber heated zone and a consistent innerair gap of about 14.3 mm is retained between the end of thetube and the surface of the sorben
29、t-retaining gauze at thesampling marked (diffusive) end of the tube. Tubes containbetween 200 and 1000 mg sorbent, depending on sorbentdensity - typically about 250 mg sorbent Type D, 300 mgsorbent Type A or 500 mg sorbent Type B. Label the tubesuniquely prior to conditioning. Do not use solvent-con
30、tainingpaints and markers or adhesive labels to label the tubes. Tubesmay be obtained, pre-marked with suitable identifiers such asunique serial numbers.7.3.1 Uptake rates in Tables 7 and 8 are given for tubes witha nominal total air gap (between the sampling surface of thesorbent bed and sampling s
31、urface of the diffusive end capFIG. 1 Schematic of a Typical Axial Diffusive SamplerD6196038(7.3.2) of 15 mm. In practice packed tube dimensions will varyslightly (11) and tubes should be rejected where the inner airgap (between stainless steel screen retaining the sorbent bedand the end of the tube
32、) is outside the range 14.0 and 14.6 mm(See Fig. 1).7.3.2 Diffusive End Caps, typically push-on, “O”-ring sealcaps fitted with a metal gauze allowing the diffusive ingress ofvapor. The size of the gauze covered opening in the samplingcap should being the same as the cross section of the tube (Fig.1)
33、. Some versions of the diffusive end cap incorporate a siliconmembrane next to the gauze to minimize ingress of water.TABLE 7 Diffusive Sampling Rates on Axial Diffusion TubesAat 20CB(15)Compound Sorbent Level Uptake Rateng.ppm-1.min-1Hydrocarbons1,3-Butadiene Molecular SieveCA 1.30n-Pentane Type A
34、A 1.46Type F B 1.77n-Hexane Type A A 1.77Cyclohexane Type A D 1.60Type D D 1.32Benzene Type E A 1.37Type C B 1.81Type A B 1.72n-Heptane Type A A 1.95Type D A 1.77Type F B 1.942-Methylhexane Type A D 1.79Type D D 1.483-Methylhexane Type A D 1.80Type D D 1.48Methylcyclohexane Type A D 1.88Type D D 1.5
35、5Toluene Type D B 1.67Type C B 2.12Type A B 1.94Type F B 2.062-Methylheptane Type A D 2.33Type D D 1.95n-Octane Type A A 2.13Type D A 2.00Xylene Type D B 1.82Type A B 2.10Type C B 2.48Ethyl Benzene Type D B 2.00Type C B 2.43Type A B 1.90Type E D 2.38Styrene Type D A 2.00Type A B 2.15n-Nonane Type A
36、A 2.40Type D A 2.12n-Propylbenzene Type A D 2.45Type D D 2.28Iso-propyl Benzene Type A D 2.38Type D D 2.281,2,3-Trimethylbenzene Type A D 2.45Type D D 2.341,2,4-Trimethylbenzene Type A D 2.26Type D D 2.161,3,5-Trimethylbenzene Type A D 2.33Type D D 2.231,3-Dimethyl-4-Ethylbenzene Type D D 2.451,4-Di
37、ethylbenzene Type D D 2.56m-Ethyltoluene Type A D 2.43Type D D 2.25o-Ethyltoluene Type A D 2.57Type D D 2.44p-Ethyltoluene Type A D 2.35Type D D 2.21n-Decane Type D A 2.30Type A A 2.47Cumene Type E D 2.50a-Pinene Type D D 2.35Type A A 2.56D6196039TABLE 7 ContinuedNaphthalene Type D A 2.55Chlorinated
38、 hydrocarbonsMethyl Chloride Type IDB 1.30Vinyl Chloride Type I B 2.001,1-Dichloro-Ethene Type I B 2.50Trichloro Trifluoroethane Type O B 3.50Chloro Trifluoromethane Type O B 1.80Dichloro Methane Type A B 1.56Type O B 1.561,2-Dichloroethane Type O B 1.90Type A B 2.03Type C B 1.72Halothane Type O B 3
39、.60Type D B 2.59Enflurane Type D B 2.29Type A D 2.80Isoflurane Type D B 2.20Type A D 2.51Bromoethane Type A A 2.55Bromobenzene Type A D 3.59Type D D 3.31Trichloromethane(Chloroform)Type C B 1.97Type O B 2.35Type A B 2.47Tetrachloromethane (CarbonTetrachloride)Type C B 3.72Type O B 2.87Trichloroethen
40、e Type A B 2.64Type O B 2.301,1,1-Trichloroethane Type A B 2.30Type O B 2.30Type C B 2.92Tetrachloroethene Type A B 3.19Type D B 2.80Type O B 2.60Type C B 2.90Epichlorohydrin Type A E 2.45Allyl Chloride Type A D 1.75Benzyl Chloride TypeED 2.72PerfluorodimethylCyclobutaneType GEB 15 mL/hPerfluorometh
41、yl-CyclopentaneType GEB 15 mL/hPerfluoromethyl-CyclohexaneType GEB 15 mL/hEsters and Glycol EthersMethyl Acetate Type A A 1.74Ethyl Acetate Type A B 1.98Type D B 1.65n-Butyl Acetate Type D B 1.93Type A A 2.60Type C B 1.93Isobutyl Acetate Type A D 2.17Type D D 1.91Sec-butyl Acetate Type A D 2.29Type
42、D D 1.90Tert-butyl Acetate Type A D 2.26Type D D 1.79Vinyl Acetate Type A D 1.93Methyl Methacrylate Type E B 2.00Type A D 2.14Type D D 1.77Methyl Acrylate Type A D 1.96Type D D 1.50Butyl Acrylate Type D D 2.00Type A D 2.11Ethylhexyl Acrylate Type D D 2.992-Methoxyethanol Type E A 1.50Type A A 2.102-
43、Ethoxyethanol Type D A 1.802-Methoxyethyl Acetate Type E A 2.80Type A B 2.08Type C B 1.81D61960310TABLE 7 ContinuedType D B 1.642-Ethoxyethyl Acetate Type A B 2.25Type D B 2.05Type C B 2.08Butoxyethanol Type A B 2.06Type D B 1.771-Methoxy-2-Propanol Type A B 1.88Type D B 1.56Type C B 1.55Methoxyprop
44、yl Acetate Type A A 2.50Type D B 2.21Type C B 2.231-Ethoxy-2-Propanol Type A B 1.94Type C B 1.64Type D B 1.652-Butoxyethyl Acetate Type A B 2.79Type C B 2.19Type D B 2.25Propoxyethanol Type A D 1.94Type D D 1.65Dipropylene Glycol MethylEtherType A A 2.70Ketones2-Butanone Type A B 1.72Type C B 1.37Ty
45、pe D B 1.34Methyl Isobutyl Ketone (2-Methyl-4-Pentanone)Type D B 1.71Type C B 1.69Type A B 2.01Cyclohexanone Type D B 1.78Type A B 1.96Type C B 1.782-Methylcyclohexanone Type D D 2.313-Methylcyclohexanone Type D D 2.224-Methylcyclohexanone Type D D 2.14Furfural Type D A 2.50Hexanal Type D D 1.64Type
46、 A A 2.06Decanal Type D D 2.32AlcoholsEthanol Type A A 1.30Propan-1-ol Type A D 1.47Propan-2-ol (Isopropanol) Type IDC 2.00Type A A 1.52n-Butanol Type A A 1.74Type D D 1.33Isobutanol Type A B 1.61Type C B 1.26Type D B 1.26Furfuryl Alcohol Type D D 2.50Tetrahydrofurfuryl Alcohol Type A D 2.39Type D D
47、 1.90MiscellaneousAcrylonitrile Type H A 1.35Type A D 1.48Acetonitrile Type HFA 1.00(2h)Type H A 0.80 (8 h)Type A A 1.48Propionitrile Type HFA 1.40(2h)Type H A 1.30 (8 h)Carbon Disulphide Type IDA 2.60Nitrous Oxide MolecularSieveGB 1.25Ethylene Oxide Type IDB 1.60Propylene Oxide Type A A 1.241,4-Dio
48、xane Type I C 3.00Allyl Glycidyl Ether Type A D 2.40Type D D 1.83Butyl Glycidyl Ether Type A D 2.61Type D D 2.36Tetrahydrofuran Type A D 1.64n-Methyl Pyrrolidone Type D C 1.83D61960311TABLE 7 ContinuedType A A 2.41n-Vinyl Pyrrolidone Type D A 2.51AThis list has been complied from sources available t
49、o ASTM. It is not complete. Unless otherwise stated, rates refer to eight hour exposure using samplers without amembrane in the diffusion cap. Users of the data are strongly advised to consult the original source material to determine the level of confidence and the range ofapplicability of the values.BThe source material does not always give the applicable temperature. See EN 13528-3 for the relationship between diffusive sampling rate and temperature.CSampler with membrane: An example of the zeolite molecular sieve known to perform as specified in this practice is molecular
