United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S4-85/055 Sept. 1985
v>EPA Project Summary
Evaluation of Polyurethane
Foam Cartridges for
Measurement of Polynuclear
Aromatic Hydrocarbons in Air
C. C. Chuang, W. E. Bresler, and S. W. Hannan
The objective of the project was to
evaluate polyurethane foam (PUF) cart-
ridges as collection media for quantifi-
cation of vapor phase polynuclear
aromatic hydrocarbons (PAHs) in air.
Two cleanup methods for PUF cart-
ridges—compression rinsing, and com-
bined compression rinsing and Soxhlet
extraction—have been evaluated. Both
methods successfully remove interfer-
ing material and background PAHs from
the PUF. The compression rinsing meth-
od is recommended because it is easier,
faster, and cheaper.
Two procedures for extraction of
PAHs from the PUF matrix, Soxhlet
extraction and compression rinsing.
were compared. Modified EPA medium
volume samplers having quartz fiber
filters to collect particles and PUF
cartridges to trap vapors were used.
Prior to sampling, known quantities of
perdeuterated PAHs were spiked into
each cleaned PUF cartridge. Eight
samplers were operated outdoors in
parallel for 24 hours. After sampling,
four PUF samples were Soxhlet-ex-
tracted with 10 percent ether/hexane
and the other four PUF samples were
extracted by alternate compression and
decompression 50 times in the same
solvent. These sample extracts were
analyzed by on-column injection, elec-
tron impact gas chromatography/mass
spectrometry (El GC/MS) to determine
PAHs. The results showed that com-
pression rinsing is comparable to con-
ventional Soxhlet extraction, and that
both methods successfully remove
PAHs from the PUF cartridges. The
compression rinsing method was then
used in the stability study.
The stability study was carried out to
determine the stability of PAHs ad-
sorbed on PUF cartridges as a function
of storage time between collection and
extraction. Two sets of PUF samples
were collected for this study. The first
set of samples was stored in the pre-
sence of light, and the second set of
samples was kept in the dark. The
storage temperature for both sets of
samples was approximately 20°C. The
samples were stored for 1,10.20. or 30
days and then extracted with 10 percent
ether/hexane. Sample extracts were
analyzed by El GC/MS. The levels of
perdeuterated benzo(a)pyrene de-
creased significantly during storage.
The rate of decrease was much faster
when the PUF cartridges were stored in
the light. Other PAH levels were not
adversely influenced by the storage
time.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory. Research Triangle
Park, NC. to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
Polynuclear aromatic compounds have
been extensively studied and have re-
ceived increased attention in studies of
air pollution in recent years because some
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of the compounds are highly carcinogenic
or mutagenic. To understand the extent of
human exposure to polynuclear aromatic
compounds, reliable sampling and analyt-
ical methodology must be established for
monitoring the concentrations of these
compounds in air. In general, the analyti-
cal methodology is well developed, but
the sampling procedures can often reduce
the validity of analytical results. Several
studies have shown that the three- to
four-ring polynuclear aromatic hydrocar-
bons (PAH) in air may be mainly in the
vapor phase and are not retained by filters
because of volatilization. A wide variety of
adsorbents such as Tenax-GC, XAD-2
resin and polyurethane foam (PDF) has
been used to sample organic vapors. The
PDF cartridge is easy to handle in the field
and has good airflow characteristics; it
has been successfully used for collection
of pesticide and polychlorinated biphenyl
(PCB) vapors.
Recently, Battelle conducted a study to
collect ambient and indoor air PAH using
a sampler with a quartz fiber filter and a
PDF back-up trap. It was observed that
the PDF cartridges changed from a pale
white to a light yellow color over a one-
week storage period. It is not known
whether this color change is associated
with any change in the PUF cartridge's
ability to retain PAHs. In a large-scale air
monitoring program, placement of the
samplers in the field and the return of
filters and traps after air collection to
analytical laboratories may take several
weeks. Therefore, it is necessary to
conduct a study to assess the stability of
PAHs adsorbed on the PUF cartridges
during storage.
The objective of this project was to
evaluate PUF cartridges for collection and
subsequent analysis of vapor phase PAH
in air.
Procedure
Two studies were performed in this
project:
a. Extraction study to evaluate two
extraction procedures, Soxhlet ex-
traction and compression rinsing, for
removal of PAH from the PUF matrix.
b. Stability study to determine the sta-
bility of PUF traps by examining the
measured PAH concentration as a
function of storage time between
collection and extraction.
The sample extracts were analyzed by
electron impact gas chromatography/
mass spectrometry (El GC/MS) to deter-
mine both native PAHs and spiked per-
deuterated PAHs.
Results
Both methods of cleaning the PUF
cartridges left only small quantities of
naphthalene in the cartridges. The ex-
traction study gave generally good re-
coveries (>85 percent) for spiked Dn-
PAHs with the exception of De-naphtha-
lene using either the Soxhlet extraction
or the compression method. The loss of
De-naphthalene was anticipated since
this compound is highly volatile. The
sampling temperature during this exper-
iment was 0°C to 10°C. Even greater
losses of this volatile compound can be
expected at higher sampling tempera-
tures.
Levels of native PAHs found in the PUF
cartridges were very similar using these
two methods. The levels of PAHs found in
the PUF cartridges, expressed as ng per
cubic meter of air sampled, ranged from
0.10 ng/m3 to 29.39 ng/m3 and 0.17
ng/m3to28.41 ng/m3 using the Soxhlet-
extraction and the compression methods,
respectively. These data demonstrate that
the compression technique is comparable
to Soxhlet-extraction in removing PAHs
from the PUF cartridges. Since significant
time and cost savings can be achieved by
using the compression method, this
method was used in the stability study.
Only volatile and semi-volatile PAHs
were found in the PUF cartridges. Higher
molecular weight PAHs (m/e>252), such
as benzo(a)pyrene and coronene, and 1-
nitropyrene were not detected in the PUF
cartridges, indicating that these com-
pounds are predominantly retained on
the filter.
The stability study was conducted to
determine whether a significant loss of
PAHs captured by PUF cartridges occurs
during the storage period. Two sets of
PUF samples were obtained for this study.
The first set of PUF samples were stored
at room temperature (~20°C) in the light,
and the second set of samples was stored
at room temperature in the dark.
Recoveries of the perdeuterated PAHs
for the first set of PUF samples (stored in
the light) ranged from 0.6 percent for D8-
naphthalene to 102.3 percent for D12-
chrysene. Low recoveries were obtained
for Da-naphthalene, which decreased
from 2.6 percent to 0.4 percent after 20
days storage. The low recovery and the
decreasing recovery trend for Da-naphtha-
lene during storage are mainly due to the
volatilization of this compound. The stor-
age time does not appear to have adverse
effects on the recoveries of D10-phenan-
threne, D-io-pyrene, and Di2-chrysene.
The variations of recovery for these
compounds were less than 15 percent
and may be due to small variations in
sampling and analysis procedures. It
should be noted that the recoveries of
Di2-benzo(a)pyrene decreased signifi-
cantly with increased storage time; the
recoveries decreased from 92.1 percent
to 11.7 percent after storage for 20 days.
It is possible that oxidation or other degra-
dation reactions of D12-BaP may occur
during storage.
I n the second set of PUF samples (stored
in the dark), the relative recovery data are
similar to those obtained with the first set
of samples. But the recovery of Di2-BaP
decreased less in the second set of
samples than in the first set. The recover-
ies decreased from 95.4 percent to 44.3
percent after 20 days storage. Even after
30 days, 29.5 percent of the Di2-BaP was
recovered. It appears that the PUF-ad-
sorbed D12-BaP is more stable in the
absence of light.
Similar recovery trends were observed
for the native PAHs. The storage time
does not significantly affect the levels of
phenanthrene, pyrene, and chrysene
found in the PUF samples. Slightly de-
creasing concentrations were detected
for naphthalene. Similar decreasing levels
were observed for anthracene, an isomer
of phenanthrene. The reactive PAH,
cyclopenta(c,d)pyrene, higher-molecular
weight PAHs (m/e>252), and 1-nitro-
pyrene were not detected in the PUF
samples.
Conclusions and
•Recommendations
Two PUF cleanup methods, compres-
sion rinsing and combined compression
rinsing and Soxhlet extraction have been
evaluated for their ability to remove
interfering material and background PAHs
from PUF cartridges. The results show
that the compression-only technique is
comparable to the combined compression
and Soxhlet extraction method. Thus the
compression method is recommended for
use in the future for time and cost savings.
The results of the extraction study
indicate that levels of both native and
perdeuterated PAHs found in the PUF
cartridges are similar using either the
Soxhlet extraction method or compres-
sion rinsing. It has been demonstrated
that both methods can successfully re-
move PAHs from the PUF cartridges.
Since significant time and cost savings
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can be achieved by using compression
rinsing, this method was used in the
stability study.
Generally, good recoveries for the
spiked perdeuteratedPAHs were obtained
for PUF samples extracted immediately
after collection, with the exception of De-
naphthalene. This finding demonstrated
that PUF cartridges cannot quantitatively
retain volatile two-ring PAHs under the
sampling conditions employed. Greater
loss of volatile components would be
expected at higher sampling tempera-
tures. It should be noted that cyclopenta-
(c,d)pyrene and higher molecular weight
PAHs (m/e>252) Were not detected in
the PUF samples. 1 -Nitropyrene was also
not found in the PUF samples.
The stabilities of PAHs adsorbed on
PUF cartridges during storage with and
without light were investigated. The
results indicated that levels of BaP de-
creased significantly during storage. The
rate of decrease was much faster when
PUF cartridges were stored in the pre-
sence of light. The levels of the remaining
PAHs were not significantly influenced by
the storage time.
Both XAD-2 resin and PUF are com-
monly used to collect PAH vapors in
ambient air sampling. A comparative
study is recommended to evaluate the
flow characteristics and the collection
efficiency for PAH vapors by using the
two adsorbents (XAD-2 and PUF) as
backup traps in ambient air sampling.
Recently, several research groups indi-
cated that extracts of clean PUF plugs
show mutagenic activity and interfere
with bioassay results. Therefore, bioassay
analysis is recommended for samples
collected from these two adsorbents. The
bioassay results can provide information
as to whether PUF plugs or XAD-2 resin
would interfere with bioassay. To charac-
terize and to compare these two adsor-
bents thoroughly, studies are also rec-
ommended to determine the stability of
PAHs captured on XAD-2 resin as a
function of time.
In this study, quartz fiber filters were
used to collect air particulate matter.
However, there are other types of filters
which can be considered for collection of
particles. Very few studies have been
conducted to evaluate filter material for
collection of particle-bound PAHs. It is
recommended that an evaluation study
be conducted to compare different types
of filters such as quartz fiber, glass fiber,
and Teflon-coated for collection of PAHs
in ambient air sampling. Several impor-
tant filter characteristics such as flow
characteristics and collection efficiency
can be addressed for different types of
filters.
Studies to determine sample stabilities
for different types of filters and to deter-
mine the effects of storage timewn PAH
samples collected on different types of
filters are also recommended.
C. C. Chuang, W. E. Bresler, and S. W. Hannan are with Battelle Columbus
Laboratories. Columbus, OH 43201.
Nancy K, Wilson is the EPA Project Officer (see below).
The complete report, entitled "Evaluation of Polyurethane Foam Cartridges for
Measurement of Polynuclear Aromatic Hydrocarbons in Air," (Order No. PB
85-245 645/AS; Cost: $9.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
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Environmental Protection
Agency
Center for Environmental Research
Information
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EPA/600/S4-85/055
00003?? PS
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