ASTM D6196-97
(Practice)Standard Practice for Selection of Sorbents and Pumped Sampling/Thermal Desorption Analysis Procedures for Volatile Organic Compunds in Air
Standard Practice for Selection of Sorbents and Pumped Sampling/Thermal Desorption Analysis Procedures for Volatile Organic Compunds in Air
SCOPE
1.1 This practice is intended to assist in the selection of sorbents and procedures for the sampling and analysis of ambient (Ref 1), indoor (2) and the workplace (3) atmospheres for a variety of common volatile organic compounds (VOCs). It may also be used for measuring emissions from materials in small or full scale environmental chambers or for human exposure assessment.
1.2 A complete listing of VOCs for which this practice has been tested, at least over part of the measurement range (1.5), is shown in Tables 1-6. For other compounds this practice shall be tested according to EN 1076 or other appropriate validation protocols (Sections 13 and 14). (4,1)
1.3 This practice is based on the sorption of VOCs from air onto selected sorbents for combinations of sorbents. Sampled air is pulled through a tube containing these sorbents. The sorbed VOCs are subsequently recovered by thermal desorption and analyzed by capillary gas chromatography.
1.4 This practice recommends a number of sorbents that can be packed in sorbent tubes, for use in the sampling of a wide range of different volatile organic compounds, in the range 0 to 400°C (v.p. 15 to 0.01 kPa at 25°C). Single-bed tubes containing for example sorbent Type A3,4 are appropriate for normal alkanes from n-C6(hexane) to n-C10(decane) and substances with similar volatility (v.p. 15 to 0.3 kPa at 25°C). More volatile materials should be sampled on stronger sorbents, such as sorbent Type B3,5. Other sorbent types than those specified may be used, if their breakthrough capacities are adequate and their thermal desorption blanks are sufficiently small. Examples are given in Appendix X2. A broader range of VOCs may be sampled using multi-bed tubes
1.5 This practice can be used for the measurement of airborne vapors of these volatile organic compounds in a concentration range of approximately 0.1 ug/m3 to 1g/m3, for individual organic compounds in 1-10 L air samples. The method is also suitable for the measurement of the airborne concentrations of individual components of volatile organic mixtures, provided that the total loading of the mixture does not exceed the capacity of the tube. Quantitative measurements are possible when using validated procedures with appropriate quality assurance measures.
1.5.1 The upper limit of the useful range is set by the sorptive capacity of the sorbent used, and by the linear dynamic range of the gas chromatograph, column and detector, or by the sample splitting capability of the analytical instrumentation used. The sorptive capacity is measured as a breakthrough volume of air, which determines the maximum air volume that must not be exceeded when sampling.
1.5.2 The lower limit of the useful range depends on the noise level of the detector and on blank levels of analyte or interfering artifacts, or both, on the sorbent tubes.
1.5.3 Artifacts are typically 3,6 and carbonaceous sorbents such as graphitized carbon, carbon molecular sieves and pure charcoals; at 1 to 5 ng levels for sorbent Type D3,7 and at 5 to 50 ng levels for Type E3,8. Method sensitivity is typically limited to 0.5 ug/m3 for 10 L air samples with this latter group of sorbent types because of their inherent high background.
1.6 This procedure is compatible with low flow rate personal sampling pumps and can be used for personal and fixed location sampling. It cannot be used to measure instantaneous or short-term fluctuations in concentration. Alternatives for on-site measurement include, but are not limited to gas chromatography and infrared spectrometry.
1.7 The sampling method gives a time-weighted average result.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
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Designation: D 6196 – 97
Standard Practice for
Selection of Sorbents and Pumped Sampling/Thermal
Desorption Analysis Procedures for Volatile Organic
Compounds in Air
This standard is issued under the fixed designation D 6196; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope amples are given in Appendix X2. A broader range of VOCs
may be sampled using multi-bed tubes.
1.1 This practice is intended to assist in the selection of
1.5 This practice can be used for the measurement of
sorbents and procedures for the sampling and analysis of
airborne vapors of these volatile organic compounds in a
ambient (Ref 1) , indoor (2) and workplace (3) atmospheres
3 3
concentration range of approximately 0.1 μg/m to 1 g/m , for
for a variety of common volatile organic compounds (VOCs).
individual organic compounds in 1–10 L air samples. The
It may also be used for measuring emissions from materials in
method is also suitable for the measurement of the airborne
small or full scale environmental chambers or for human
concentrations of individual components of volatile organic
exposure assessment.
mixtures, provided that the total loading of the mixture does
1.2 A complete listing of VOCs for which this practice has
not exceed the capacity of the tube. Quantitative measurements
been tested, at least over part of the measurement range (1.5),
are possible when using validated procedures with appropriate
is shown in Tables 1-6. For other compounds this practice shall
quality assurance measures.
be tested according to EN 1076 or other appropriate validation
1.5.1 The upper limit of the useful range is set by the
protocols (Sections 13 and 14). (4, 1)
sorptive capacity of the sorbent used, and by the linear
1.3 This practice is based on the sorption of VOCs from air
dynamic range of the gas chromatograph, column and detector,
onto selected sorbents or combinations of sorbents. Sampled
or by the sample splitting capability of the analytical instru-
air is pulled through a tube containing these sorbents. The
mentation used. The sorptive capacity is measured as a
sorbed VOCs are subsequently recovered by thermal desorp-
breakthrough volume of air, which determines the maximum
tion and analyzed by capillary gas chromatography.
air volume that must not be exceeded when sampling.
1.4 This practice recommends a number of sorbents that can
1.5.2 The lower limit of the useful range depends on the
be packed in sorbent tubes, for use in the sampling of a wide
noise level of the detector and on blank levels of analyte or
range of different volatile organic compounds, in the range 0 to
interfering artifacts, or both, on the sorbent tubes.
400°C (v.p. 15 to 0.01 kPa at 25°C). Single-bed tubes contain-
3,4
1.5.3 Artifacts are typically <1ng for well conditioned
ing for example sorbent Type A are appropriate for normal
,
3 6
sorbent Type C and carbonaceous sorbents such as graphi-
alkanes from n-C (hexane) to n-C (decane) and substances
6 10
tized carbon, carbon molecular sieves and pure charcoals; at 1
with similar volatility (v.p. 15 to 0.3 kPa at 25°C). More
,
3 7
to 5 ng levels for sorbent Type D and at 5 to 50 ng levels for
volatile materials should be sampled on stronger sorbents, such
3,5
other porous polymers such as sorbent Type A and sorbent
as sorbent Type B . Other sorbent types than those specified
, 3
3 8
Type E . Method sensitivity is typically limited to 0.5 μg/m
may be used, if their breakthrough capacities are adequate and
for 10 L air samples with this latter group of sorbent types
their thermal desorption blanks are sufficiently small. Ex-
because of their inherent high background.
1.6 This procedure is compatible with low flow rate per-
sonal sampling pumps and can be used for personal and fixed
This practice is under the jurisdiction of ASTM Committee D-22 on Sampling
and Analysis of Atmospheres and is the direct responsibility of Subcommittee
location sampling. It cannot be used to measure instantaneous
D22.05 on Indoor Air.
or short-term fluctuations in concentration. Alternatives for
Current edition approved Nov. 10, 1997. Published January 1998.
2 on-site measurement include, but are not limited to gas
The bold face numbers in parentheses refer to the list of references at the end
chromatography and infrared spectrometry.
of this practice.
If you are aware of alternative sorbent types, please provide this information to
ASTM Headquarters. Your comments will be carefully considered at a meeting of
the responsible technical committee, which you may attend. An example of sorbent Type C known to perform as specified in this practice
An example of sorbent Type A known to perform as specified in this practice is Tenax GR manufactured by Enka Research Institute NV, NL.
is Chromosorb 106 manufactured by Manville Corp., USA and available from An example of sorbent Type D known to perform as specified in this practice
several commercial sources. is “Tenax TA” manufactured by Enka Research Institute NV, NL.
5 8
An example of sorbent Type B known to perform as specified in this practice An example of sorbent Type E known to perform as specified in this practice
is Carboxen 569 manufactured by Supelco, Inc., USA. is Porapak Q manufactured by Waters Associates Inc., USA.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6196–97
1.7 The sampling method gives a time-weighted average 2.1 ASTM Standards:
result. D 1356 Terminology Relating to Atmospheric Sampling
1.8 This standard does not purport to address all of the and Analysis
safety concerns, if any, associated with its use. It is the D 3686 Practice for Sampling Atmospheres to Collect Or-
responsibility of the user of this standard to establish appro- ganic Compound Vapors (Activated Charcoal Tube Ad-
priate safety and health practices and determine the applica- sorption Method)
bility of regulatory limitations prior to use.
2. Referenced Documents Annual Book of ASTM Standards, Vol 11.03.
A
TABLE 1 Extrapolated Retention Volumes and Safe Sampling Volumes for Organic Vapors Sampled on a 300 mg Sorbent Type A
Sorbent Tube at 20°C
Retention Safe
Desorption
Boiling Point, Vapor Volume (L), Sampling SSV/g
Organic compound Temperature, Reference
°C Pressure, kPa 25°C Volume (L/g)
°C
B
(SSV ) (L)
Hydrocarbons
C
Propane -42 – 0.17 0.09 0.29 (9)
Pentane 35 56 23.4 11.7 39 130 (9)
Hexane 69 16 73.8 36.9 123 160 (9)
Heptane 98 4.7 325 160 530 180 (3)
Octane 125 1.4 2076 1000 3300 200 (3)
Nonane 151 – 14k 7k 23k 220 (3)
Decane 174 – 62k 31k 104k 250 (9)
Benzene 80 10.1 57 28.5 95 160 (9)
Toluene 111 2.9 165 80 270 200 (3)
Xylene 138-144 0.67–0.87 1554 770 2600 250 (3)
Ethylbenzene 136 0.93 730 360 1200 250 (3)
Trimethylbenzene 165-176 - 5650 2800 9300 250 (3)
a pinene 53 0.51 6600 3300 11k 200 (9)
Chlorinated Hydrocarbons
Dichloromethane 40 47 6.9 3.45 11.5 130 (9)
Carbon tetrachloride 76 12 44 22 73 160 (3)
1,2-dichloroethane 84 8.4 34 17 67 150 (3)
Trichloroethylene 2.7 80 40 140 170 (3)
1,1,1-trichloroethane 74 13.3 42.6 21.3 71 140 (9)
Esters and Glycol Ethers
Methyl acetate 58 22.8 14.04 7.02 23.4 125 (9)
Ethyl acetate 71 9.7 39 20 67 150 (3)
Propyl acetate 102 3.3 297 150 500 170 (3)
Isopropyl acetate 90 6.3 147 75 250 165 (3)
Butyl acetate 126 1.0 1460 730 2400 95 (3)
Isobutyl acetate 115 1.9 880 440 1500 90 (3)
t-butyl acetate 98 – 327 160 530 185 (3)
Methoxyethanol 125 0.8 45 22.5 75 140 (9)
Ethoxyethanol 136 0.51 150 75 200 250 (3)
Methoxyethyl acetate 145 0.27 1720 860 2900 250 (3)
Ethoxyethyl acetate 156 0.16 8100 4000 13k 250 (3)
Ketones
Acetone 56 24.6 2.9 1.5 5 120 (3)
Methyl ethyl ketone 80 10.3 21 10.5 35 145 (9)
Methyl isobutyl ketone 118 0.8 490 250 830 190 (3)
Alcohols
C
Methanol 65 12.3 0.78 0.39 1.3 (9)
Ethanol 78 5.9 3.18 1.59 5.3 120 (9)
n-propanol 97 1.9 17 8 27 125 (3)
Isopropanol 82 4.3 88 44 145 120 (3)
n-butanol 118 0.67 135 67.5 225 170 (9)
Isobutanol 108 1.6 60 30 100 150 (3)
Others
C
Ethylene oxide 11 147 0.84 0.42 1.4 100 (9)
Propylene oxide 34 59 2.04 1.02 3.4 120 (9)
Hexanal 131 – 1680 840 2800 220 (9)
A
An example of sorbent Type A known to perform as specified in this practice is Chromosorb 106 manufactured by Manville Corp., USA.
B
SSV; see 11.5.1 and 11.5.2.
C
SSV below recommended 1L. sorbent Type B is preferred (Table 2).
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6196–97
TABLE 2 Extrapolated Retention Volumes and Safe Sampling
centage, by a combination of bias and precision usually
Volumes for Organic Vapors Sampled on a 500 mg Sorbent Type
according to the formula:
A
B Sorbent Tube at 20°C (9)
?x¯ – x ? 1 2s
ref
Safe
OU 5 3 100 (1)
Boiling Vapor Retention Desorption
x
Organic Sampling SSV/g, ref
Point, Pressure, Volume, Temperature,
Compound Volume, L/g
°C kPa 25°C L °C
B
SSV ,L where:
x¯ = mean value of results of a number (n) of repeated
Propane –42 – 7.2 3.6 7.2 200
C
Methanol 65 12.3 4 2 4 200
measurements
Ethylene 11 147 140 70 140 250
x = true or accepted reference value of concentration,
ref
oxide
and
A
An example of sorbent Type B known to perform as specified in this practice is
s = standard deviation of measurements.
Carboxen 569 manufactured by Supelco, Inc., USA.
B
SSV; see 11.5.1 and 11.5.2.
NOTE 1—In strict mathematical terms there is no way to combine
C
Desorption recovery is poor (see Table 7).
precision (a variance) and bias (an absolute number). However, by
occupational hygiene precedent and time honored convention they have
been combined according to the above formula (Clause 3.7 of
E 355 Practice for Gas Chromatography Terms and Rela-
EN 482:1994).
tionships
3.2.6 precision—the closeness of agreement between the
2.2 ISO Standards:
results obtained by applying the method several times under
ISO 5725 Precision of Test Methods
prescribed conditions (ISO 6879). Precision may be expressed
ISO 6249 Gas Analysis. Preparation of Calibration Gas
either as repeatability or reproducibility (ISO 5725)
Mixtures. Permeation Method
3.2.7 pumped sampler—a device which is capable of taking
ISO 6879 Air Quality. Performance Characteristics and Re-
samples of gases and vapors from the atmosphere and consist-
lated Concepts for Air Quality Measuring Methods 1983
ing of a sampling medium, such as a sorbent tube, and an air
2.3 CEN Standards:
sampling pump. The sampling pump shall conform to the
EN 482 Workplace Atmospheres. General Requirements for
specifications in 18.3.
the Performance of Procedures for the Measurement of
3.2.8 safe sampling volume—70 % of breakthrough volume
Chemical Agents.
(3.2.2) or 50 % of chromatographically determined retention
EN 1076 Workplace Atmospheres. Pumped Sorbent Tubes
volume.
for the Determination of Gases and Vapours. Require-
3.2.9 sorbent strength—term to describe the affinity of
ments and Test Methods.
sorbents for VOCs; a stronger sorbent is one which offers
EN 1232 Workplace Atmospheres. Pumps for Personal
greater safe sampling volumes for VOCs relative to another,
Sampling of Chemical Agents. Requirements and Test
weaker, sorbent.
Methods.
3.2.10 sorbent tube—a tube, usually made of metal or glass,
containing an active sorbent or a reagent-impregnated support,
3. Terminology
through which sampled atmosphere is passed at a rate con-
3.1 Definitions—Refer to Terminology D 1356 and Practice
trolled by an air sampling pump.
E 355 for definitions of terms used in this practice.
3.2 Definitions of Terms Specific to This Standard:
4. Summary of Practice
3.2.1 bias—consistent deviation of the results of a measure-
4.1 A suitable sorbent type or series of sorbents should be
ment process from the true value of the air quality character-
selected for the compound or mixture to be sampled. The
istic itself (ISO 6879).
sorbents selected should be arranged in order of increasing
3.2.2 breakthrough volume—the volume of a known atmo-
sorbent strength by linking tubes containing the individual
sphere that can be passed through the tube before the concen-
sorbents together in series. Alternatively, a single tube contain-
tration of the vapor eluting from the tube reaches 5 % of the
ing several sorbents in series may be used. Provided suitable
applied test concentration.
sorbents are chosen, volatile organic components are retained
3.2.3 desorption effıciency—the ratio of the mass of analyte
by the sorbent tube(s) and thus are removed from the flowing
desorbed from a sampling device to that applied.
air stream. The collected vapor (on each tube) is desorbed by
3.2.4 loading—the product of concentration expressed in
heat and is transferred under inert carrier gas into a gas
13 3
ppb or mg/m and the sampled atmosphere volume (flow rate
chromatograph (GC) equipped with a capillary column and
x sampling time).
either a conventional detector (such as the flame ionization or
3.2.5 overall uncertainty (OU)—quantity used to character-
electron capture detector (ECD)) or a mass spectrometric
ize, as a whole, the uncertainty of the result given by an
detector, where it is analyzed. Where the sample to be analyzed
apparatus or measuring procedure. It is expressed, as a per-
contains unknown components (indoor/ambient air applica-
tions), preliminary analysis of typical samples using mass
spectrometry should be undertaken.
Annual Book of ASTM Standards, Vol 14.02.
Available from American National Standards Institute, 11 W. 42nd St., 13th
5. Significance and Use
floor, New York, NY 10036
12 5.1 This practice is recommended for use in measuring the
Available from Comité Européen de Normalisation, Brussels.
13 –9
Volume fraction, (f)=10 . concentration of VOCs in ambient, indoor, and workplace
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D6196–97
A
TABLE 3 Extrapolated Retention Volumes and Safe Sampling Volumes for Organic Vapors Sampled on a 200 mg Sorbent Type D
Sorbent Tube at 20°C (3)
Safe
Vapor Desorption
Boiling Point, Retention Sampling SSV/g,
Organic Compound Pressure, Temperature,
°C Volume, L Volume L/g
kPa 25°C °C
B
SSV ,L
Hydrocarbons
Hexane 69
...
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