United States
Environmental Protection
Agency
Atmospheric Research and
Exposure Assessment Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-94/113 January 1995
EPA Project Summary
Field Test of a Generic Method
For Halogenated Hydrocarbons:
A VOST Test at a Chemical
Manufacturing Facility
J.F. McGaughey, J.T. Bursey, and R.G. Merrill
Laboratory evaluation studies were
performed for the volatile halogenated
organic compounds (VHOCs) listed in
Title III of the Clean Air Act Amend-
ments (CAAA) of 1990 to determine
chromatographic retention times, recov-
eries from sorbent, and method detec-
tion limits, as well as to design (where
necessary), construct, and evaluate dy-
namic spiking equipment and proce-
dures for VOST. An initial field evalua-
tion study was conducted for the VOST
(SW-846 sampling Method 0030, ana-
lytical Method 5041) with dynamic spik-
ing of VHOCs. A chemical manufactur-
ing facility was selected as a second
test site. The presence of low levels of
some of the compounds of interest was
established by the VOST analysis of
samples collected during a presurvey.
For the field evaluation study, qua-
druple trains were operated from 4 col-
located sampling probes, with 2 dy-
namically-spiked trains and 2 unspiked
trains. A sampling scheme to meet the
requirements of method evaluation was
designed statistically (following the
guidelines for EPA Method 301), and
the data were evaluated statistically. Of
23 VHOCs tested, the VOST showed
acceptable performance with respect
to recovery and precision for 17.
This Project Summary was developed
by EPA's Atmospheric Research and
Exposure Assessment Laboratory, Re-
search Triangle Park, NC, to announce
key findings of the research project
that is fully documented in a separate
report of the same title (see Project
Report ordering information at back).
Introduction
The validation of a method for a par-
ticular analyte or group of analytes means
that the performance of the methodology
for these analytes has been established
and demonstrated through field tests at
the type of source category of interest,
and that the precision and bias of the
method have been established experimen-
tally. The U. S. EPA, under the authority
of Title III of the CAAA of 1990, required
the identification and/or validation of sam-
pling and analytical methods for the
VHOCs listed in Table 1. The candidate
method is VOST, which consists of SW-
846 Sampling Method 0030 and SW-846
Analytical Method 5040 or 5041. EPA de-
termined that the VOST method should
first be evaluated in a laboratory environ-
ment to establish the veracity of the spik-
ing procedure and the potential applicabil-
ity of the analytical procedures for the
compounds listed in Table 1.
The VOST was evaluated at a coal-
fired power plant using quadruple VOST
trains sampling from 4 collocated sam-
pling probes to provide further verification
of the dynamic spiking methodology in a
non-laboratory environment and to assess
the added effect of sampling a combus-
tion matrix upon the performance of the
methodology. Data obtained in the first
field evaluation showed that the VOST did
not perform acceptably for all of the can-
didate analytes. The methodology was not
expected to show acceptable performance
for all of the candidate analytes listed in
Table 1, but all of the candidate analytes
were included in the testing to demon-
strate definitively when the methodology
Printed on Recycled Paper
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would not perform well and to provide
quantitative data to assess method per-
formance. Three of the candidate ana-
lytes could not be analyzed by the VOST
analytical methodology: epichlorohydrin,
bis(chloromethyl) ether, and chloromethyl
methyl ether. These 3 compounds are po-
lar, water-soluble, and very reactive, so
they either could not be purged from the
water or reacted with the water.
A second field evaluation study was
conducted at a chemical manufacturing
facility where chemical waste was inciner-
ated. Dynamic spiking of the analytes listed
in Table"! was performed, using 4 collo-
cated sampling probes with 4 similar VOST
trains. The guidelines of EPA Method 301
were used to design the sampling strat-
egy to ensure that adequate samples were
available for statistical evaluation of bias
and precision.
Procedure
The objective of this program was to
perform a second field evaluation of the
VOST method (sampling method SW-846
Method 0030; analytical method, SW-846
Method 5041) at a chemical manufactur-
ing facility that incinerated chemical waste,
to allow the collection of sufficient data to
be able to establish the bias and precision
of the method for the VHOCs listed in
Title III of the CAAA of 1990.
To achieve this objective, a field test
site was selected to allow access for the
quadruple sampling trains required for test-
ing, with 4 collocated sampling probes.
Collection and evaluation of the data fol-
lowed one of the acceptable approaches
detailed in EPA Method 301: dynamic ana-
lyte spiking. The criteria for acceptable
performance of the method for an analyte
are recovery within the range of 50% to
150% with precision (expressed as per-
cent relative standard deviation of repli-
cate determinations) of 50 or less.
Sampling was performed by withdraw-
ing gas from a single port in the stack
through a Quad probe, then directing the
sampled gas simultaneously to 4 similar
VOST sampling trains. The Quad probe
consists of 4 heated probes that can be
inserted into the stack as one unit. The
front end of the Quad probe was posi-
tioned in the center of the stack and re-
mained in that location during each day of
testing. No traverse of the stack was per-
formed with the Quad probe. The true
concentrations of the components of the
stack gas were of no interest to this pro-
gram as long as any quantities of the
compounds of interest were equal for each
train. For VOST sampling during the field
evaluation, two of the trains of each Quad
run were dynamically spiked and two were
unspiked. Sampling procedures followed
Method 0030.
Dynamic spiking of candidate VOST
compounds was performed using a com-
pressed gas cylinder containing the
VHOCs. The boiling point maximum of
100°C cited in Method 0030 was extended
to approximately 135°C to include chlo-
robenzene and ethylene dibromide, com-
pounds frequently determined by the
VOST methodology. The apparatus shown
in Figure 1 was used for dynamic spiking
in the field, with the spiking gas allowed to
flow through the spiking apparatus for 2
hr before directing the flow to the sam-
pling trains to minimize any adsorptive
Table 1. Halogenated Compounds for Which Laboratory Testing has Determined the Applicability of the VOST Method
Compound
Boiling point (°C)
Comments
allyl chloride
bisfchloromethyl) ether
carbon tetrachloride
chlorobenzene
chloroform
chloromethyl methyl ether
chloroprene
1,3-dichloropropylene
epichlorohydrin
ethyl chloride (chloroethane)
ethylene dichloride (1,2-dibromoethane)
ethyl/dene dichloride (1,2-dichloroethane)
methyl bromide (bromomethane)
methyl chloride (chloromethane)
methyl chloroform (1,1,1-trichloroethane)
methylene chloride
methyl iodide (iodomethane)
propylene dichloride (1,2-dichloropropane)
tetrachloroethylene
1,1,2-trichloroethane
trichloroethylene
vinyl chloride
vinyl bromide
vinylidene chloride (1,1-dichloroethylene)
44-46
106'
77
132'
60.6-61.5
55-57
59.4
105-106?
115-17T
123
131-132'
83
43
-24.2'
74-76
39.8-40
41-43
95-96
121'
110-115'
86.9
-13.43
16*
30-32
Acceptable performance in laboratory
Decomposes in water; cannot be analyzed
Recovery too high in laboratory study
Acceptable performance in laboratory
Acceptable performance in laboratory
Decomposes in water; cannot be analyzed
Acceptable performance in laboratory
Acceptable performance in laboratory
Decomposes in water; cannot be analyzed
Acceptable performance in laboratory
Acceptable performance in laboratory
Acceptable performance in laboratory
Recovery unacceptably high in laboratory
Erratic and unacceptable in laboratory
Recovery too high in laboratory study
Recovery too high in laboratory study
Acceptable performance in laboratory
Acceptable performance in laboratory
Acceptable performance in laboratory
Acceptable performance in laboratory
Acceptable performance in laboratory
Acceptable performance in laboratory
Acceptable performance in laboratory
Acceptable performance in laboratory
1 Above the maximum VOST boiling point of 100°C; included in the testing because compounds in the range of 100-132°C are frequently tested by the VOST method.
2 Boiling temperature at 730 mm Hg.
3 Below the common lower temperature limit of 30°C usually used for VOST.
' Boiling temperature at 750 mm Hg.
-------
Regulator
(temperature controlled)
Certified
standard
(spiking
compounds)
Chassis (temperature controlled)
To train A
•*• To train B
Fine metering
valves
(Flow control)
1/4" Teflon line
(Heat traced
and insulated)
O
Temperature
display
Variacs
(To provide temperature control)
Thermocouple selector
Figure 1. VOST spiking apparatus.
losses in the sampling trains. The con-
centration of compounds in the cylinder
was verified by laboratory GC/MS and GC/
multiple detector analysis of a diluted
sample prepared in a SUMMA®*-polished
canister.
Analysis of field samples was performed
according to SW-846 Method 5041, ana-
lyzing each tube individually to establish
distribution of compounds. A total of 6
complete and valid Quad runs (24 Tenax®/
Tenax®-charcoal pairs, 12 spiked, 12
unspiked) is required to satisfy the re-
quirements of the field validation protocol.
However, a total of 10 Quad runs was
performed to provide back-up samples in
the event that any samples became in-
valid due to breakage or loss during analy-
sis. The 2 tubes associated with each
sample pair were analyzed separately, al-
ways analyzing the Tenax®-charcoal tube
first to minimize the possibility of carryover
from the front tube, where higher com-
pound concentrations were expected. All
VOST sampling tubes were transported
* Mention of trade names or commercial products does
not constitute endorsement or recommendation for
use.
and stored at 4°C and were analyzed
within 30 days after collection.
Results and Discussion
The complete analytical results for each
sampling train, showing recoveries of dy-
namically-spiked compounds and of sur-
rogate compounds for the front and back
tubes individually are shown in Appendix
A of the project report. No corrections
were performed for background concen-
trations because analyte concentrations
in the background samples were less than
five times the Method Detection Limit.
Mean analyte recoveries and precision for
6 sampling runs are summarized in Table
2.
The results for the first and second
VOST field evaluation studies are com-
pared in Table 3. Using the criteria for
acceptable performance of recovery be-
tween 50 and 150%, with precision (as
expressed by relative standard deviation)
of 50 or less, acceptable performance of
the VOST methodology for a given com-
pound is indicated in Table 3 by an aster-
isk.
Methyl chloride exhibited recoveries far
above the acceptable range, consistent
with results obtained in previous studies.
The common factor in the excessive re-
coveries for methyl chloride appears to be
formation of the compound in the time
that the halogenated organic compounds
are adsorbed on the sorbent tubes. Method
8240 shows acceptable and reproducible
performance for methyl chloride, but sor-
bent residence times are minimal in this
analytical methodology. Where sorbent
residence time is minimal (e.g., spiked
sorbent tubes are analyzed immediately),
recoveries are within the reasonable range,
although somewhat high. When methyl
chloride and other halogenated com-
pounds are retained on the sorbent for a
period of days, excessive values for me-
thyl chloride recovery are observed. Ana-
lytical results for methyl chloride using the
VOST methodology are biased high, fre-
quently by a factor of ten or more.
Analyte distribution is summarized in
Table 4. As expected, methyl chloride,
ethyl chloride, methyl bromide, and vinyl
chloride are found almost exclusively on
the back tube, because these compounds
break through Tenax® very readily. How-
ever, methyl bromide and ethyl chloride
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Table 2. Summary of Mean Recovery and Precision for 6 VOST Sampling Runs Using Dynamic Spiking
Recovery 50-150%—Precision < 50% Relative Standard Deviation (RSD)
Compound Average recovery (%)
%RSD
propylene dichloride (1,2-dichloropropane)
trichloroethylene
chloroform
methyl chloroform (1,1,1-trichloroethane)
methylene chloride
ethylidene dichloride (1,1-dichloroethane)
chlorobenzene
carbon tetrachloride
1,1,2-trichloroethane
ethylene dibromide (1,2-dibromoethane)
cis-1,3-dichloropropene
vinylidene chloride (1,1-dichloroethylene)
chloroprene
ethylene dichloride (1,2-dichloroethane)
tetrachloroethene
methyl bromide (bromomethane)
trans-1,3-dichloropropene
Acceptable recovery, unacceptable precision
methyl iodide (iodomethane)
Unacceptable recovery (low), acceptable precision
vinyl chloride
allyl chloride (3-chlompropene)
ethyl chloride (chloroethane)
vinyl bromide
Unacceptable recovery (high), unacceptable precision
methyl chloride (chloromethane)
121
119
91.3
91.1
89.9
82.2
81.2
81.2
79.7
79.6
79.5
77.8
72.4
72.3
60.1
54.8
52.3
79.5
41.8
35.6
33.7
29.8
243
24.8
26.2
31.1
24.6
14.3
23.3
22.1
23.6
27.2
37.4
27.6
24.2
23.0
37.5
27.9
26.2
35.4
63.1
44.6
33.3
36.9
29.7
62.8
frequently show an approximately even
distribution between the front tube and
the back tube. Other compounds are dis-
tributed between the front tube and back
tube, with the highest compound concen-
tration on the front tube. Highly haloge-
nated compounds such as methylene chlo-
ride, carbon tetrachloride, and methyl chlo-
roform show a distribution between front
and back tubes, but with a clear predomi-
nance on the front tube. Using the crite-
rion of 30% distribution on the back tube
as an indicator of breakthrough (Hand-
book: Quality Assurance/Quality Control
(QA/QC) Procedures for Hazardous Waste
Incineration, EPA/625/6-89/023, January,
1990), no breakthrough was observed for
any compound.
Conclusions
The following conclusions can be drawn
from the data obtained in VOST field evalu-
ation:
• The VOST method performed accept-
ably for the majority of the candidate
VHOCs in 2 field tests. The VOST
methodology showed unacceptable
performance for only 2 compounds in
both field evaluation studies: methyl
chloride and allyl chloride.
• The VOST method performed accept-
ably for the following compounds in
only 1 field evaluation: vinyl chloride,
ethyl chloride, vinyl bromide, ethylene
dibromide, and chloroprene. The suc-
cess of the methodology for these
analytes is source-dependent.
• Vinyl chloride, allyl chloride, chloro-
prene, and vinyl bromide all show
marginal or unsuccessful performance
in the VOST methodology. The pres-
ence of the double-bond in the ana-
lyte molecule appears to significantly
decrease the probability of successful
performance of the VOST method.
On the basis of laboratory and field
evaluation studies for the VHOCs from
Title III of the CAM of 1990, the following
recommendations are made:
• Consideration of the chemical proper-
ties of the compounds which were not
amenable to the VOST analytical
methodology (epichlorohydrin, chloro-
methyl methyl ether, bisfchloromethyl]
ether) predicts that successful perfor-
mance is very unlikely. These com
pounds are reactive, polar, and wa
ter-soluble. A method other than thi
VOST will be required for the sue
cessful sampling and analysis of thesi
types of compounds.
Methyl chloride has demonstrated ex
cessively high values for recoverie
in two field evaluation studies, as we
as in laboratory studies. Because c
this high bias, the VOST is not rec
ommended as a sampling and ana
lyticat method for this compound.
Further study of the VOST should b
performed and/or VOST data shoul
be collected in order to set appropr
ate recovery limits for the surrogate
recommended in the analytics
method. At present, the surrogate
can only be used qualitatively: poc
surrogate recoveries indicate prot
lems with the matrix or the methodo
ogy.
Modification or replacement of th
VOST methodology should be inves
tigated to provide a feasible samplin
and analytical method for the volatili
polar, water-soluble compounds liste
in Title III of the CAAA of 1990.
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Table 3. Comparison of Results for First and Second VOST Field Evaluations
Compound
First field test'
Recovery(%) RSD (%)
Second field test'
Recovery (%) RSD (%)
methyl chloride
ethylidene dichloride
chlorobenzene
vinyl chloride
vinylidene chloride (1, 1-dichloroethylene)
chloroform
propylene dichloride (1,2-dichloropropane)
methyl bromide (bromomethane)
ethyl chloride (chloroethane)
methylene chloride
methyl chloroform (1, 1, 1-trichloroethane)
carbon tetrachloride
ethylene dichloride (1 ,2-dichloroethane)
trichloroethylene
cis- 1 ,3-dichloropropene
trans- 1 ,3-dichloropropene
1, 1 ,2-trichloroethane
tetrachloroethene
methyl iodide (iodomethane)
ally! chloride (3-chloropropene)
ethylene dibromide (1 ,2-dibromoethane)
chloroprene
vinyl bromide
937
75.7'
88.2'
110.4'
88.0'
81.8'
67.2'
53.7'
50.3'
77.7'
110'
107'
76.6'
126'
137'
135'
98.0'
97.7'
72.8'
29.9
34.9
40.1
60.7'
53.8
13.7
22.0
27.3
31.3
14.8
9.6
20.2
28.7
27.1
43.5
47.2
33.0
15.6
26.0
38.1
22.1
21.9
37.6
19.5
31.6
22.4
34.3
243
82.2'
81.2'
41.8
77.8'
91.3'
121'
54.8'
33.7
89.9'
91.1'
81.2'
72.3'
119'
79.5'
52.3'
79.7'
60. r
79.5
35.6
79.6'
72.4'
29.8
62.8
23.3
22.1
44.6
24.2
24.6
24.8
26.2
36.9
14.3
31.1
23.6
37.5
26.2
27.6
35.4
27.2
27.9
63.1
33.3
37.4
23.0
29.7
Chkxomethyl methyl ether, bix(chloromethyl) ether, and epichlorohydrin could not be analyzed by the VOST methodology.
* Acceptable performance by the analyte in the VOST method, using acceptability criteria of 50-150% recovery with percent Relative Standard Deviation (RSD) of 50 or less.
1 Mean of 6 runs (twelve pairs) unconnected for background.
Table 4. Distribution Between Front and Back Tubes According to Compound
Compound
Average recover (front)
Average recovery (back)
Compounds recovered on the front tube (> 90% on front tube)
cis- 1,3-dichloropropene
trans-1 ,3-dichloropropene
ethylene dichloride (1,2-dibromoethane)
trichloroethene
tetrachloroethene
chlorobenzene
propylene dichloride (1,2-dichloropropane)
chloroprene
1, 1 ,2-trichloroethane
ethylene dichloride (1, 1-dichloroethane)
chloroform
allyl chloride (3-chloropropene)
methyl iodide (iodomethane)
ethylene dichloride (1 ,2-dichloroethane)
100.0
99.9
99.9
99.7
99.6
99.5
99.5
99.0
97.7
96.8
95.8
93.7
93.2
92.0
0.0
0.1
0.1
0.3
0.4
0.5
0.5
1.0
2.3
3.2
4.2
6.3
6.8
8.0
Compounds distributed between front and back tubes
methyl chloride (chloromethane)
vinyl chloride
methyl bromide (bromomethane)
chloroethane
vinyl bromide
methylene chloride (chloromethane)
carbon tetrachloride
methyl chloroform (1,1,1-trichloroethane)
16.5
19.3
36.5
55.1
73.2
81.7
84.5
86.3
83.5
80.7
63.5
44.9
26.8
18.3
15.5
13.7
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James F. McGaughey, Joan T. Bursey, and Raymond G. Merrill are with Radian
Corporation, Research Triangle Park, NC 27709.
Merrill D. Jackson is the EPA Project Officer (see below).
The complete report, entitled "Field Test of a Generic Method for Halogenated
Hydrocarbons: A VOST Test at a Chemical Manufacturing Facility," (Order No.
PB95-129144/AS; Cost: $19.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Atmospheric Research and Exposure Assessment Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
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