1、Designation: D6345 10Standard Guide forSelection of Methods for Active, Integrative Sampling ofVolatile Organic Compounds in Air1This standard is issued under the fixed designation D6345; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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 guide provides assistance in the selection of activeintegrative sampling methods, in which the v
3、olatile organicanalytes are collected from air over a period of time by drawingthe air into the sampling device, with subsequent recovery foranalysis. Where available, specific ASTM test methods andpractices are referenced.1.2 Guidance is provided for the selection of active sam-pling methods based
4、either on collection of an untreated airsample (whole air samples) or selective sampling using sorbentconcentration techniques that selectively concentrate compo-nents in air. Advantages and disadvantages of specific collec-tion vehicles are presented.1.3 This guide does not cover the use of cryogen
5、icallycooled field sampling devices used in some automated analysissystems. Detailed instructions for cryogenic recovery of com-pounds captured as whole air samples or thermally desorbedfrom sorbents are typically covered in standard methods forsample analysis and are beyond the scope of this guide.
6、1.4 Both thermal and solvent desorption techniques forsample recovery are discussed.1.5 Organic compounds are classified on the basis of vaporpressure as very volatile, volatile, semivolatile and nonvolatile.Physical characteristics of many volatile organic compounds(VOCs) are provided to aid in sel
7、ection of sampling techniquesfor VOC measurement. Semivolatile and nonvolatile organiccompounds are defined in the guide to help guide users avoidmisidentifying compounds that are not covered in this guide.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement
8、 are included in thisstandard.1.7 This standard does not purport to address all of thesafety concerns, 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 limitation
9、s prior to use.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheresD1357 Practice for Planning the Sampling of the AmbientAtmosphereD3686 Practice for Sampling Atmospheres to Collect Or-ganic Compound Vapors (Activated Charcoal Tube Ad-sorption
10、 Method)D3687 Practice for Analysis of Organic Compound VaporsCollected by the Activated Charcoal Tube AdsorptionMethodD5197 Test Method for Determination of Formaldehydeand Other Carbonyl Compounds in Air (Active SamplerMethodology)D5466 Test Method for Determination of Volatile OrganicChemicals in
11、 Atmospheres (Canister Sampling Methodol-ogy)D5953M Test Method for Determination of Non-MethaneOrganic Compounds (NMOC) in Ambient Air UsingCryogenic Preconcentration and Direct Flame IonizationDetection MethodD6196 Practice for Selection of Sorbents, Sampling, andThermal Desorption Analysis Proced
12、ures for Volatile Or-ganic Compounds in Air3. Terminology3.1 DefinitionsFor definitions of terms used in this guiderefer to Terminology D1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 cryofocusthe process of concentrating compoundsfrom an air sample for subsequent analysis by collecti
13、on on atrap cooled with a cryogen to very low temperatures (forexample, -186C).3.2.1.1 DiscussionCryogenic traps used for cryofocusingare typically U-shaped stainless steel tubes filled with glass1This guide is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the direct responsibili
14、ty of Subcommittee D22.05 on Indoor Air.Current edition approved April 1, 2010. Published June 2010. Originallyapproved in 1998. Last previous edition approved in 2004 as D6345 - 98(2004)1.DOI: 10.1520/D6345-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cust
15、omer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.beads or other inert material. An e
16、xample of such a cryofocus-ing trap is given in Test Method D5953M. Compounds aretypically released from cryogenic traps into the analyticalsystem by rapid heating to elevated temperatures. Sorbent-filled tubes cooled to sub-ambient temperatures (for example,-30C) have also been used for this purpos
17、e.3.2.2 very volatile organic compounds (VVOCs)Low mo-lecular weight organic compounds that possess vapor pressuresgreater than 15 kPa at 25C and boiling points typically below30C.4. Significance and Use4.1 This guide provides a broad perspective on techniquesthat can be used by environmental manage
18、rs for selecting VOCair monitoring methods. It summarizes various methods formeasurement of VOC in air derived from a variety of sourcesand experiences and incorporates them into condensed guide-lines. This guide provides a common basis for selectingmethods for VOC measurement as well a discussion o
19、f thelimitations of typical methods.4.2 This guide should be used during the planning stages ofan air monitoring program along with other applicable guidesand practices (for example, D1357) to select ASTM or otherappropriate methods.5. Characteristics of Organic Compounds5.1 Physical and chemical ch
20、aracteristics of VOCs areavailable from numerous references (1, 2, 3, 4).3The propertiesof the VOCs listed under the Clean Air Act of 1990 (5) arepresented in Table 1 and Table 2.TABLE 1 Properties of Clean Air Act Very Volatile Organic HAPsA,BVapor Boiling WaterPressure Point Solubility (g/L Custom
21、ary Reactivity inCompound CAS No. (kPa at 25C) (C) at C) Classification AirAcetaldehyde 75-07-0 127 21 33.0 / 25 PolarAcrolein 107-02-8 29 53 100 /21 Polar ReactiveAllyl chloride 107-05-1 45 45 19.5 / 20 Non-Polar1.3-Butadiene 106-99-0 267 -5 Insoluble Non-Polar Reactive (?)Carbon disulfide 75-15-0
22、35 47 100 / 20 PolarChloroform 67-66-3 21 61 0.85 / 20-24 Non-PolarChloromethly methylether107-30-2 30 59 Reacts Polar ReactiveChloroprene 126-99-8 30 59 Slightly soluble Non-PolarDiazomethane 334-88-3 373 -23 Reacts Polar Highly reactive1,1-Dimethylhydrazine 57-14-7 21 63 Reacts Non-Polar Reactive
23、(?)1,2-Epoxybutane 106-88-7 22 63 100 / 17 Polar ReactiveEthyl chloride 75-00-3 133 13 100 / 20 Non-PolarEthyleneimine 151-56-4 21 56 Miscible Polar Reactive (?)Ethylene oxide 75-21-8 147 11 Miscible Polar ReactiveEthylidene dichloride 75-34-3 31 57 100 / 20.5 PolarHexane 110-54-3 16 69 100 / 19 Pol
24、ar Highly reactive (?)Vinyl bromide 593-60-2 147 16 Insoluble Non-PolarVinyl chloride 75-01-4 427 -14 Slightly soluble Non-PolarVinylidene chloride 75-35-4 67 32 5-10 / 21 Non-PolarACompounds with vapor pressures 15 kPa.BData taken from Ref. (3).TABLE 2 Properties of Clean Air Act Volatile Organic H
25、APA,BVaporPressure Water(kPa at Boiling Point Solubility Customary ReactivityCompound CAS No. 25C) (C) (g/L at C) Classification in AirAcetonitrile 75-05-8 9.86 82 100 / 22 PolarAcetophenone 98-86-2 0.13 202 6.3 / 25 Polar3The boldface numbers in parentheses refer to the list of references at the en
26、d ofthis standard.D6345 102TABLE 2 ContinuedVaporPressure Water(kPa at Boiling Point Solubility Customary ReactivityCompound CAS No. 25C) (C) (g/L at C) Classification in AirAcrylamide 79-06-1 0.07 125/25 mm 100 / 22 Polar ReactiveAcrylic acid 79-10-7 0.43 141 100 / 17 PolarAcrylonitrile 107-13-1 13
27、.33 77 716.0 / 254 PolarAniline 62-53-3 0.09 184 1.0 / 254 Polaro-Anisidine 90-04-0 0.01 224.0 100 / 21.5 PolarChloroacetic acid 79-11-8 0.09 189 100 / 20 PolarChlorobenzene 108-90-7 1.17 132 100 / 22 PolarDimethyl sulfate 77-78-1 0.13 188 100 / 20 Polar Reactive(?)1,4-Dioxane 123-91-1 4.93 101 100
28、/ 20 PolarEpichlorohydrin 106-89-8 1.60 117 50-100- / 22 Polar Highly reactiveEthyl acrylate 140-88-5 3.91 100 4.2 / 204 PolarEthylbenzene 100-41-4 0.93 136 100 / 22 PolarEthyl dibromide 106-93-4 1.47 132 100 / 18 PolarIsophorone 78-59-1 0.05 215 0.1-1 / 18 PolarMethanol 67-56-1 12.26 65 100 / 21 Po
29、larMethyl chloroform 71-55-6 13.33 74 100 / 19 PolarMethylhydrazine 60-34-3 6.61 88 100 / 19 Polar ReactiveN-Nitrosomorpholine 59-89-2 0.04 225 100 / 19 PolarPhenol 108-95-2 0.03 182 50-100- / 19 Polar1,3-Propane sultone 1120-71-4 0.27 180/30 mm 0.1 Polar Reactive(?)Beta-Propiolactone 57-57-8 0.45 D
30、ecomposes at 162 37.0 / 20 PolarPropylene dichloride 78-87-5 5.60 97 0.1 / 21.5 Non-Polar PesticideQuinoline 91-25-5 0.01 238 0.1 / 22.5 PolarStyrene 100-42-5 0.88 145 1 / 19 Non-PolarStyrene oxide 96-09-3 0.04 194 1 / 19.5 Polar Highly reactive1,1,2,2-Tetrachloroethane79-34-5 0.67 146 0.1 / 22 Non-
31、PolarTetrachloroethylene 127-18-4 1.87 121 0.1 / 17 Non-PolarToluene 108-88-3 2.93 111 1 / 18 Non-Polaro-Toluidine 95-53-4 0.01 200 5-10 / 15 Polar1,2,4-Trichlorobenzene 120-82-1 0.02 213 1 / 21 Non-Polar1,1,2-Trichloroethane 79-00-5 2.53 114 1-5 / 20 Non-PolarTrichloroethylene 79-01-6 2.67 87 1 / 2
32、1 Non-PolarTriethylamine 121-44-8 7.20 90 Soluble Polar Reactive (?); strong base2,2,4-Trimethylpentane540-84-1 5.41 99 Insoluble Non-polarVinyl acetate 108-05-4 11.06 72 Insoluble Polaro-Xylene 95-47-6 0.67 144 Insoluble Non-PolarD6345 103TABLE 2 ContinuedVaporPressure Water(kPa at Boiling Point So
33、lubility Customary ReactivityCompound CAS No. 25C) (C) (g/L at C) Classification in Airm-Xylene 108-38-3 0.80 139 Insoluble Non-Polarp-Xylene 106-42-3 0.87 138 Insoluble Non-PolarACompounds with vapor pressures between 102and 15 kPa.BData taken from Ref. (4).5.2 Organic compounds can be divided into
34、 four groupsbased on volatility (1).5.2.1 VOCs with vapor pressures above 15 kPa at 25C(boiling points typically below 30C) are sometimes referred toas very volatile organic compounds (VVOCs). At room tem-perature and atmospheric pressure, VVOCs are present in thegas phase in air. Due to their high
35、vapor pressures, VVOCs aregenerally more difficult to collect and retain on sorbents thanother VOCs.5.2.2 Volatile organic compounds typically have vapor pres-sures above 10-2kPa at 25C (typical boiling points from about30 to 180C). VOCs with boiling points at the upper end of therange still have a
36、significant vapor pressure at room tempera-ture and atmospheric pressure. At room temperature andatmospheric pressure VOCs are present in the gas phase in air.5.2.3 Semivolatile organic compounds (SVOCs) typicallyhave vapor pressures between 10-2and 10-8kPa at 25C(typical boiling points from 180 to
37、350C). SVOCs may bepresent in both the vapor and particulate phases (1).5.2.4 Nonvolatile organic compounds have vapor pressuresbelow 10-8kPa at 25C (boiling points typically above 300C).Nonvolatile organic compounds occur primarily in the particu-late phase.NOTE 1Boiling points are not reliable pre
38、dictors of volatility. Somecompounds that boil above 300C are volatile at room temperature.5.3 The polarity, water solubility, and reactivity of a VOCare critical in the choice of the sampling and analyticalmethods.5.3.1 VOCs range in polarity from nonpolar (for example,propane) to very polar (for e
39、xample, acetic acid). Polar organiccompounds typically contain oxygen, nitrogen, sulfur, or otherheteroatoms and may be categorized as either ionizable orpolarizable. The former category includes alcohols, phenols,amines, and carboxylic acids; the latter includes ketones,ethers, nitro-compounds, nit
40、riles, and isocyanates.5.3.2 VOCs also range in reactivity from stable (for ex-ample, benzene) to highly reactive (for example, diaz-omethane). Polar compounds are often also reactive com-pounds and are generally more difficult to recover fromsampling devices and present special analytical problemsb
41、ecause of their chemical reactivities, affinities for metal andother surfaces, and water solubilities. These problems are moresevere with ionizable compounds.5.4 The sampling location and concentration of VOCs arealso important in selecting a monitoring method. VOCs aretypically found in indoor air
42、in residences, offices, and publicaccess buildings at concentrations ranging from 0.1 to 100g/m3. VOC data may also be reported in parts per billion byvolume (ppbv). The conversion between these reporting unitsis shown in Eq 1 and requires the molecular weight and thestandard molar volume at standar
43、d temperature (273.15 K,0C) and pressure (101.3 kPa, 760 mm Hg):Cppbv! 5 Cg/m3! 3 22.4/molecular weight (1)NOTE 2Indoor sampling is usually performed at temperature near 293K (20C). The standard molar volume at this temperature is 24.1 L/mol.6. Selection of Sampling Methods for VOCs6.1 The first cri
44、teria for selection of an appropriate methodfor sampling are the physical and chemical characteristics ofthe compounds to be monitored. Once the analyte has beencharacterized as a volatile compound, the appropriate measure-ment method (sampling and analysis) is chosen. Samplingmethods can be active
45、or passive.6.1.1 Active methods employ some means of setting andcontrolling the air sampling rate (for example pump, syringe,or other vacuum source with a flow-controller).6.1.2 Passive/diffusive sampling methods have samplingrates that depend on the molecular diffusion rate, samplingtemperature, le
46、ngth and area of the diffusive path, and otherconditions.6.1.3 Active sampling methods can be divided into threebroad types: whole air methods which use canisters, bags, orsyringes; sorbent collection methods; and specialized samplingmethods for reactive compounds.6.1.4 Sampling can also be integrat
47、ive (accumulative) orcontinuous (real-time).6.2 Whole Air Sampling:6.2.1 If the VOC of interest is relatively stable, and volatileenough to be recovered from an inert container, then whole airsampling may be a valid choice. The major advantage of wholeair sampling is the ability to trap the most vol
48、atile compounds,since the entire air sample is collected and retained forsubsequent analysis. A fraction of this sample is then concen-trated under controlled conditions in the laboratory immedi-ately prior to analysis.6.2.2 Bags made from polyfluorinated polymer, polyester,or polyvinylidene plastic
49、s have been used for whole airsampling, but have the disadvantage of limited (24 to 48 h)useful sample holding times and should be used only whenanalyses can be performed within that time limit (6, 7).Shipping of bags is usually restricted to ground transport sincechanging pressures in aircraft shipping cause sample loss orcontamination. Bags also have the disadvantage of being bulkyand are inconvenient for personal monitoring.6.2.3 Passivated stainless steel canisters are superior to bagsfor collection of whole air samples. Two ASTM test method
