United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S4-84-036 June 1984
<&EPA Project Summary
Performance Audit Results for
POHC: VOST and Bag
Measurement Methods
R.K.M. Jayanty, J.A. Sokash, W.F. Gutknecht, and C.E. Decker
Gas cylinders containing a mixture of
five organic compounds in a balance
gas of nitrogen were used to conduct
performance audits to evaluate the
accuracy and precision of the sampling
and analysis phases of the Volatile
Organic Sampling Train (VOST) and
bag measurement methods. The five
compounds in the audit cylinders were:
carbon tetrachloride, chloroform, per-
chloroethylene, vinyl chloride, and
benzene. The audit cylinders contained
compounds in two concentration ran-
ges. A low concentration cylinder in the
range of 7 to 90 ppb for each POHC was
used for the evaluation of the VOST
method. A high concentration cylinder
in the range of 90 to 430 ppb for each
POHC was used for the evaluation of
the bag measurement method.
Thus far, four laboratories have
participated in the VOST audits but only
two laboratories have been involved in
the bag audits. The objectives of the
audit program, the audit procedures
used, the laboratories audited, the
performance audit results, and pertinent
conclusions and recommendations are
presented in the project report. The
audit results indicate that laboratories
can analyze POHC with accuracy to
within the limits of ±50 percent that are
stated in the VOST protocol.
Compound stabilities have been
determined through multiple analyses
of the cylinders contents. Over the 4-
month study period, the low ppb audit
mixture of five organic compounds was
found to be stable. It is recommended
that a performance audit using these
audit cylinders be conducted during
each hazardous waste trail burn test
to assess and document the accuracy
and precision of POHC measurements.
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
information at back).
Introduction
Under the regulations of the Resource
Conservation and Recovery Act (RCRA) of
1976, the Administrator of the U.S.
Environmental Protection .Agency (EPA)
has promulgated performance standards
for owners and operators of hazardous
waste treatment, storage, and disposal
facilities. The RCRA regulations, which
deal specifically with hazardous waste
incineration, are described in the Code of
Federal Regulations, Title 40 Parts 122,
264 and 265. Hazardous waste incinera-
tors are tightly regulated under the Act.
The determination of destruction/remov-
al efficiency (ORE) for principle organic
hazardous constituents (POHC) requires
a reliable sampling and analytical method
which may be used with confidence
during the hazardous waste trial test
burns. EPA is currently recommending a
Volatile Organic Sampling Train (VOST)
method for collection and analysis of
volatile (bp 30-100°C) POHC emissions
from hazardous waste incinerators (Ref.
1).
Research Triangle Institute (RTI) was
directed by the Quality Assurance
Division of EPA's Environmental Moni-
toring Systems Laboratory, Research
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Triangle Park, North Carolina to conduct
performance audits to evaluate the
accuracy and precision of the sampling
and analysis phases of the VOST and bag
measurement methods. The main objec-
tives of this audit program are: (1) to
demonstrate that cylinder gases can be
used to assess and document the
accuracy and precision of POHC measure-
ments during trial burns of hazardous
waste, (2) to screen the sampling and
analysis phases of the VOST/bag methods
to determine the principle sources of
measurement error, (3) to evaluate the
proficiency of laboratories currently
using the VOST or bag methods for POHC
measurements, and (4) to determine the
stability of the POHC at parts-per-billion
(ppb) concentrations in gas cylinders. RTI
used a multicomponent mixture of five
organics in compressed gas cylinders as
an audit material to evaluate the objectives
of the program at four laboratories. The
various activities performed during the
study and the results obtained are
discussed in the project report.
Table 1. Summary of Audit Results
Audit Procedures
Gas cylinders containing a mixture of
five organic compounds in a balance gas
of nitrogen were used as the audit
material for this study. The five compounds
in the audit cylinders were: carbon
tetrachloride, chloroform, perchloroethyl-
lene, vinyl chloride, and benzene. The
audit cylinders contained compounds in
two concentration ranges. A low concen-
tration cylinder in the range of 7 to 90
ppb for each POHC was used for the
evaluation of the VOST method. A high
concentration cylinder in the range of 90
to 430 ppb for each POHC was used for
the evaluation of the bag measurement
method. The audit cylinders were prepared
and analyzed by the National Bureau of
Standards (NBS) under an Interagency
Agreement with EPA. After NBS analysis,
the audit cylinders were sent to the
Environmental Sciences and Engineering
Unit at RTI. RTI analyzed the cylinders
before and after conducting the VOST/bag
audits to demonstrate the stability of the
organic compounds during the audit
period. RTI analysis results were in close
agreement with the NBS-measured
concentrations (see Table 1). In addition,
the NBS and RTI analyses showed the
organic compounds to be stable over the
entire study period (approximately 4
months).
Performance audits were conducted at
four laboratories. The laboratories were:
Battelle Columbus Laboratories; PEDCo
Environmental, Inc.; Radian Corporation
(formerly TRW Environmental Engineering
Division); and Engineering Science, Inc.
(Sampling was performed by Engineering
Science and GC/MS analysis was per-
formed by the Analytical and Chemical
Sciences Unit at RTI). All four laboratories
participated in the VOST audits but only
two laboratories were involved in the bag
audits. All participating laboratories were
told the name and concentration range of
each compound prior to the audit. The
proposed audit sequence and general
instructions for the sampling and analysis
of volatile POHC from Quality Assurance
(QA) audit cylinders were sent to each
Audit Gas
True Cone and Stability
LabA'"
LabB
LabC'
LabD '
Activity
Audited
VOST
(Both
sampling &
analysis!
VOST
Car-
tridges
analysis
only
BAG
(Both
sampling &
analysis/
Direct Gas
Analysis by
GC Only
Audit
Gases
carbon tetra-
chloride
chloroform
perchloro-
ethylene
vinyl chloride
bemene
carbon tetra-
chloride
chloroform
perchtoro-
ethylene
vinyl chloride
benzene
carbon tetra-
chloride
chloroform
perch/or o-
ethylene
vinyl chloride
benzene
carbon tetra-
chloride
chloroform
perchloro-
ethylene
vinyl chloride
benzene
NBS
Cone.
ppb
21
23
29
31
18
21
23
29
31
18
141
120
126
154
133
141
120
126
154
133
ry-ri 11) (2) 151
10/83
ppb
21.7
238
30.4
34.9
19.4
21.7
238
30.4
349
19.4
148
117
128
161
136
148
117
128
161
136
12/83
ppb
21.1
23.2
31.1
28.0
20.0
21.1
232
31.1
28.0
20.0
149
117
136
158
143
149
117
136
158
143
Range
(ppb/
5.9-15.3
21.7-25.2
29.7-36.3
12.8-18.2
22.9-24. 1
10.4-14.9
23.6-25.0
37.5-38.5
131-20.8
25.4-27.0
222-230
160-163
153-181
86-126
147-167
223-252
169-176
97-104
87-136
160-180
Average c51
ppb
10.4
23 1
339
15.5
235
12.7
24.3
38.0
164
26.2
225
161
165
1O4
157
238
173
101
118
173
%3
Ace.
-50
17
-50
31
-40
6
31
-47
46
60
34
31
-33
18
69
44
-20
-23
30
Range
Ippbt
24.5-30.4
28.8-29.8
35.4-41.4
7.8-13.0
22.9-248
22.6-24.0
25.8-27.0
30.9-358
7.7-21.4
21.5-234
121-124
99-103
70-73
96-105
90-101
131-135
115-117
116-126
101-107
117-119
Average l51
ppb
26.6
29.4
38.8
10.5
23.7
23.3
26.4
33.4
14.6
22.5
123
101
71
101
97
133
116
121
104
118
%3
Ace.
27
28
34
-66
32
11
15
15
-53
25
-13
-16
-44
-34
-27
-6
-3
-4
-33
-11
Average l5'
Range %3
(ppb) ppb Ace.
22.0-24.0 23.O 10
26.0-30.0 27.7 20
-NOTAUDITED-
-NOT AUDITED-
15.0-17.0 16.3 -9
22.0-27.0 23.7 13
26.0-38.0 30.3 32
-NOTAUDITED-
-NOTAUDITED-
21.0-21.0 21.0 17
-NOTAUDITED-
-NOTAUDITED-
Range
(ppb!
15.0-21.0
180-19.0
29.0-36.0
24.0-32.0
190-19.0
19.0-20.0
18.0-19.0
33.0-36.0
32.0-39.0
17.0-190
Average l5'
%3
ppb Ace.
18.0 -14
18.5 -20
32.5 12
28.0 -10
19.0 6
19.5 -7
185 -20
34.5 19
35.5 15
180 0
--NOTAUDITED--
-NOTAUDITED-
1 NBS (Gas and Particulate Division} and RTI (Environmental Sciences and Engineering unit) values were obtained by direct GC analysis.
2 RTI values are shown to illustrate cylinder gas stability.
% accuracy = Lab average value ' NBS va/ue
x 100
NBS value
' Analysis by GC and not GC/MS.
5 Each concentration for RTI and all the laboratory values are an average of two or three analyses.
6 Analyses were performed 2 to 3 weeks after sample collection.
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laboratory prior to the actual audit. The
audits were conducted by R.K.M. Jayanty
and J.A. Sokash, RTI, at the four laboratory
sites. The sampling and analysis proce-
dures used by the respective laboratories
are summarized in the report.
Summary of Results
Volatile Organic Sampling
Train (VOST) Measurements
Audits were conducted at four labora-
tories to evaluate the combined sampling
and analysis accuracy and precision of
the VOST method. In addition, accuracy and
precision of the analytical component
were also evaluated. Each laboratory
collected three pairs of samples using the
entire VOST system and three pairs of
samples on VOST organic sorption cartrid-
ges only from the VOST audit gas
cylinder. All samples were collected from
the audit cylinder at a flow rate of 0.5
L/min for 20 min for a total volume of
approximately 10L. The collected samples
were analyzed by three of the laboratories
(Laboratories A, B, and D—see Table 1)
using thermal desorption, purge and trap
and gas chromatography/mass spectro-
metry (GC/MS). One laboratory (Labora-
tory C), however, analyzed the collected
samples by gas chromatography using
PID/Hall detectors. Laboratory C analyzed
only three organics (carbon tetrachloride,
chloroform and benzene). All four labora-
tories analyzed at least one pair of VOST
(Tenax-Tenax/charcoal) cartridges as
blanks. The analysis results reported by
the laboratories for each individual
measurement of the five compounds and
their percent accuracy relative to the
NBS-determined concentrations are
tabulated and included in the project
report. A summary of all VOST audit
results including laboratory accuracy is
shown in Table 1. From Table 1, the range
of percent accuracy for the entire VOST,
in general, is found to be within the ±50
percent accuracy limits reported in the
VOST protocol (Ref. 1). The only exceptions
are the vinyl chloride and carbon tetra-
chloride results from Laboratory A and
vinyl chloride results from Laboratory B,
which were outside the expected accuracy
limits described in the VOST protocol.
Similar ranges of percent accuracy were
found for directly-loaded VOST cartridge
samples. Blank concentrations for the
five compounds from the Tenax and
Tenax/charcoal cartridges were found to
be <1.0 ppb under laboratory conditions.
Bag Measurements
i Audits were conducted at two labora-
tories (Laboratories A and B) to evaluate
the combined sampling and analysis
accuracy and precision for bag measure-
ments. In addition, the accuracy and
precision of the analytical component
only was evaluated. Each laboratory
collected audit gas in a bag three times for
analysis. Between each analysis the bag
was evacuated, filled with dry nitrogen,
and then analyzed to show the absence of
POHC memory efforts. Each bag sample
was analyzed in triplicate by direct
injection of the sample from the bag into
the gas chromatograph. The audit gas was
also analyzed three times directly from the
audit cylinder. A summary of the percent
accuracies for each compound for both
bag measurement (sampling plus analysis)
and direct analysis only are shown in
Table 1. In general, the range of percent
accuracy was within ±50 percent.
Conclusions and
Recommendations
Cylinders gases containing low ppb
audit mixture of five organic compounds
(carbon tetrachloride, chloroform, per-
chloroethylene, vinyl chloride, and
benzene) have been used successfully for
performance audits on VOST and bag
methods to assess the accuracy and
precision for the combined sampling and
analysis of POHC. Four laboratories may
not be representative of the type of
results that currently could be expected
from all laboratories conducting POHC
measurements during trial burns. How-
ever, the audit results indicated that
laboratories can analyze POHC with
accuracy to within the limits of ±50
percent that are stated in the VOST
protocol. The audit results also indicate
that the analysis phase and not sampling
is the principal source of error for both the
VOST and bag methods. Blank concentra-
tions for VOST cartridges were found to be
less than 1 ppb for each of the five
organics under laboratory conditions.
Over the 4-month study period, the low
ppb audit mixture of five organic com-
pounds was found to be stable. It is
recommended that a performance audit
using EPA audit cylinders be conducted
during each hazardous waste trial burn
test to assess and document the accuracy
and precision of POHC measurements. In
addition, an audit may be useful prior to
the trial burn to evaluate the proficiency
of the source test organization for POHC
measurements.
Reference
1. Protocol for the Collection and
Analysis of Volatile POHC Using
VOST, August 1983. Copy available
from Technical Support Office,
Industrial Environmental Research
Laboratory, U.S. Environmental
Protection Agency, Research Triangle
Park, NC 27711.
R. K. M. Jayanty. J. A. Sokash, W. F. Gutknecht. and C. E. Decker are with
Research Triangle Institute. Research Triangle Park. NC 27709.
D. J. von Lehmden is the EPA Project Officer (see below).
The complete report, entitled "Performance Audit Results for POHC: VOST and
Bag Measurement Methods." (Order No. PB 84-187 889; Cost: $8.50. 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:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC27711
U.S. GOVERNMENT PRINTING OFFICE; 1984 — 759-015/7725
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