United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S4-86/034 March 1987
&EPA Project Summary
Comparison of Polyurethane Foam
and XAD-2 Resin as Collection
Media for Polynuclear Aromatic
Hydrocarbons in Air
J. C. Chuang, S. W. Hannan, and J. R. Koetz
The objective of this project was to
(1) evaluate the collection and retention
efficiency for polynuclear aromatic*
hydrocarbons (PAH) adsorbed or spiked
on polyurethane (PUF) and XAD-2 car-
tridges, and (2) to compare the effect
of sampling temperature on retention
efficiency for PAH spiked on PUF and
XAD-2 resin cartridges.
Six EPA medium volume samplers
were set up to collect ambient air for
24 hours at a 6.7 cfm flow rate. Quartz
fiber filters and XAD-2 resin or quartz
fiber filters and PUF in series were used
to collect particulate-bound PAH and
vapor-phase PAH. Prior to sampling,
two PUF and two XAD-2 cartridges
were spiked with known amounts (2 ng
of each compound) of native and per-
deuterated PAH. One PUF and one
XAD-2 resin cartridge were not spiked
and were used as background samples.
This experiment was performed at two
different ambient temperature ranges:
66-86°F and 17-27°F. The filter sam-
ples were not analyzed in this study.
The XAD-2 samples were extracted with
methylene chloride, and the PUF
samples were extracted with 10 percent
diethyl ether in hexane. These sample
extracts were then analyzed by electron
impact gas chromatography/mass
spectrometry.
Results from the non-spiked samples
showed that the levels of PAH were in
good agreement between the two ad-
sorbents except for some volatile PAH,
such as naphthalene. The levels of
XAD-2-adsorbed naphthalene were
more than 10 times higher than those
of PUF-adsorbed naphthalene. For the
spiked PAH, good recoveries were ob-
tained from both adsorbents, except
for a few compounds. The spiked XAD-
2 resin gave substantially higher re-
coveries than did the spiked PUF, and
approximately 80 percent of the spiked
Dg-naphthalene was recovered from
XAD-2 after ambient air exposure even
at summer ambient temperatures (66-
86°F). Low recoveries of D10-phenan-
threne were observed from PUF in the
summer experiment, but these re-
coveries improved significantly in the
winter experiment at lower sampling
temperatures. Thus, the loss of this
PAH was mainly due to volatilization.
The recoveries of some other PAH were
also improved to some extent from both
adsorbents at lower sampling tempera-
tures. A lower recovery of cyclopenta
[c,d]pyrene was obtained from PUF than
from XAD-2 resin. The recovery of this
compound did not improve at lower
sampling temperatures. In fact, its re-
coveries were smaller at lower tempera-
tures for both adsorbents. It appears
that cyclopenta[c,d]pyrene is lost
through degradation, not through vola-
tilization. Thus, XAD-2 resin has higher
collection efficiency for volatile PAH
than PUF, as well as higher retention
efficiency for both volatile and reactive
PAH. The retention efficiency for some
volatile PAH for both adsorbents can be
improved by lowering the sampling
temperature.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Research Triangle
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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 in-
formation at back).
Introduction
Polynuclear aromatic hydrocarbons
(PAH) have been extensively studied and
have received increased attention in
studies of air pollution m recent years
because some of these compounds are
highly carcinogenic or mutagenic. To
understand the extent of human exposure
to PAH, reliable sampling and analytical
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 two- to four-
ring PAH in air may be mainly in the
vapor phase and are not retained by
filters because of volatilization. Quartz
fiber and glass fiber filters are typically
used in sampling air particles. A wide
variety of adsorbents such as Tenax GC,
XAD-2 resin and polyurethane foam (PUF)
has been used to sample PAH vapors. All
these adsorbents have been demonstrated
to have a high collection efficiency for
certain PAH. Each of these adsorbents
has several drawbacks as well as virtues.
For instance, Tenax GC is expensive and
requires a lengthy purification procedure
prior to use. It is also known to degrade to
diphenylquinones, if exposed to hot,
oxidizing conditions such as those in stack
gas emissions. Both XAD-2 resin and
PUF have been successfully used in air
sampling for PAH. The overall comparative
effectiveness of these adsorbents and
the degree to which quantification of the
PAH is affected by sampling, handling
and storage, however, have not been
fully investigated. Recently, Battelle has
conducted studies to evaluate the stability
of PAH collected on PUF or XAD-2 resin
and quartz fiber filters as a function of
storage conditions. For comparison, the
collection and retention efficiency of PUF
and XAD-2 resin for PAH was investigated
in this project.
The objective was to evaluate the col-
lection and retention efficiency for PAH
adsorbed or spiked on PUF and XAD-2
resin cartridges, and to compare the ef-
fect of sampling temperature (summer
and winter ambient temperatures) on the
retention efficiency of these two adsor-
bents for PAH.
Procedure
Two sets of three samplers were located
in parallel approximately two feet apart,
with the three samplers separated from
each other by about one foot. PUF car-
tridges were used in one set of three
samplers, and XAD-2 cartridges were
used in the other set. Quartz fiber filters
were located upstream of the PUF or
XAD-2 resin in all samplers. Prior to
sampling, two each of the three PUF and
XAD-2 resin cartridges were spiked with
perdeuterated PAH (2 M9 of each). Air
was then sampled for 24 hours at a 6.7
cfm flow rate. The experiments were
performed twice under the same sampling
conditions, once with an ambient tem-
perature range of 66-86°F and once with
a range of 17-27°F. The PUF and XAD-2
samples were Soxhlet-extracted with 10%
ether/hexane (PUF) or methylene chloride
(XAD-2) for 16 hours. The extracts were
concentrated by Kuderna-Danish evap-
oration and analyzed by electron impact
gas chromatography/mass spectrometry.
Results
The results showed that within each
experiment (summer and winter), good
agreement between PAH ambient back-
ground levels determined from PUF and
XAD-2 resm were obtained except for
volatile PAH. Background levels of
naphthalene adsorbed on XAD-2 resin
were 24 and 12 times higher than those
on PUF in the summer and the winter
experiments, respectively. The phenan-
threne levels were also slightly higher
than those on PUF in the summer experi-
ment, but identical levels of this com-
pound were observed in both adsorbents
in the winter experiments.
The spiked XAD-2 resin gave substan-
tially higher D8-naphthalene recoveries
than did the spiked PUF in both the
summer and winter experiments Lower
recoveries of spiked D10-phenanthrene
and spiked native anthracene were ob-
tained from the PUF than from the XAD-2
resin at summer temperatures. These
recoveries from the PUF improved signifi-
cantly at winter temperatures and were
comparable to those from XAD-2 resin.
Lower recoveries of cyclopenta[c,d]pyrene
were obtained from the PUF than from
XAD-2 resin. The recoveries of this
compound did not improve at lower
ambient temperature. In fact, relative
lower recoveries of cyclopenta[c,d]pyrene
from both XAD-2 and PUF were observed
in the winter experiment. The recovery
data for the remaining PAH were good,
and better retention for some PAH was
observed at lower sampling temperature.
Conclusions and
Recommendations
Generally, it appears that XAD-2 resin
has a better collection efficiency for
volatile PAH than does PUF. The collection
efficiency of PUF for some volatile PAH
can be improved at lower sampling
temperature. Both adsorbents have
shown good retention for most of the
spiked PAH except for a few volatile and
reactive PAH. In conclusion, XAD-2 resin
has better retention efficiency for volatile
PAH, such as naphthalene, and reactive
PAH, such as cyclopenta[c,d]pyrene.
Lower sampling temperatures can im-
prove the retention efficiency for volatile
PAH, but not for reactive PAH.
The losses of the reactive PAH, such as
cyclopenta[c,d]pyrene, during sampling
and sample storage have been confirmed
both in this study and a previous study.
The reactive PAH, cyclopenta[c,d]pyrene,
contains a five-membered ring and is
readily oxidizable due to the olefmic
nature of the relatively localized carbon-
carbon double bond. One research group
has reported that pyrene-1,10-dicarbox-
ylic anhydride, a direct-acting mutagen,
is a possible oxidative derivative of the
cyclopenta[c,d]pyrene. Another research
ground has found a dicarboxylic acid
anhydride from PAH with molecular
weight of 202 in airborne paniculate
matter. The potential parent compounds,
acephenanthrylene and aceanthrylene
with molecular weights of 202, also have
five-membered rings that are easy to
oxidize. Since some oxidized PAH deriva-
tives show mutagenicity, it is important
to know whether these compounds are
from sampling artifacts. Therefore, it is
recommended that a study be conducted
to determine to what extent these com-
pounds are from sampling artifacts.
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J. C. Chuang, S. W. Hannan. andJ. R. Koetzare with Battelle Columbus Division,
Columbus. OH 43201 -2693.
Nancy K. Wilson is the EPA Project Officer (see below).
The complete report, entitled "Comparison of Polyurethane Foam and XAD-
2 Resin as Co/lection Media for Polynuclear Aromatic Hydrocarbons in Air,"
(Order No. PB 87-129 979/AS; Cost: $11.95, 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
United States
Environmental Protection
Agency
Onter for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use S300
EPA/600/S4-86/034
OC00329
60604
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