United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S4-86/014 Apr. 1986
SERA Project Summary
Validation of the Volatile Organic
Sampling Train (VOST) Protocol
Thomas J. Logan, Robert G. Fuerst,
M. Rodney Midgett, and John Prohaska
The measurement of volatile organic
emissions from a hazardous waste in-
cinerator is one of the more difficult
source testing problems. Specific
compounds called principal organic
hazardous constituents (POHCs) are to
be identified and quantified at levels of
0.5 to 100 ppb in hot, wet incinerator
exhaust gas, which may also contain
high particulate and acid levels. The
Volatile Organic Sampling Train (VOST)
Protocol which describes the practices
used by laboratories making these
measurements allows for several alter-
native designs and operating proce-
dures. Because its use is currently being
recommended by regulatory agencies
to measure emissions for compliance
determinations, the VOST Protocol was
subjected to a methods validation
study. .
The VOST Protocol validation pro-
gram consists of two phases: a labora-
tory validation and a field test validation.
The laboratory validation examined the
results of sampling six different POHCs
at two different concentration levels,
two tube configuration designs, two
moisture levels and other procedural
variations. The field test validation
determined the expected precision and
recovery results when spiking the gas
stream of a hazardous waste incinerator
with five specific POHCs. Recom-
mendations relative to method improve-
ments, quality assurance measures and
other aspects of VOST sampling and
analysis are also discussed in the full
report.
Tli/* Protect Summary was developed
by EPA'* Environmental Monitoring Sys-
tems Laboratory, Research Triangle
Park, NC, to announce key finding* of
the research project that Is fully docu-
mented In two separate volumes (see
Project Report ordering Information at
back).
Introduction
The Code of Federal Regulations, Title
40, Part 264, requires that a destruction
and removal efficiency (ORE) of 99.99
percent be achieved for each principal
organic hazardous constituent (POHC)
designated in the Trial Burn Permit (1).
The calculation of ORE requires sampling
and analysis to quantify POHCs in the
waste feed material and stack gas ef-
fluent. The manual entitled Sampling and
Analysis Methods for Hazardous Waste
Combustion provides information of
applicable methods for collection and
analyses of POHCs in process streams of
hazardous waste incinerator units (2).
Protocol for the Collection and Analysis
of Volatile POHCs using VOST (VOST
Protocol) describes the Volatile Organic
Sampling Train (VOST) used to measure
POHCs in the stack gas effluent (3).
Specific POHCs may be identified and
quantified at low levels of 0.5 to 100 ppb
in hot, wet incinerator exhaust gas, which
may also contain high particulate and
acid levels. The VOST has already been
used to collect a significant amount of
background emission data, and it is cur-
rently being recommended by regulatory
agencies as the means to measure emis-
sions for compliance trial burns; there-
fore, the EPA considered the validation of
the VOST Protocol to be an essential
research objective. The validation program
consisted of two phases: laboratory
validation studies (Phase I) (4) and field
test validation studies (Phase II) (5). This
-------
summary describes the experimental
program to evaluate as many of the ac-
ceptable practices as possible under con-
trolled conditions in the laboratory and
under typical incinerator conditions in
the field. The results of the laboratory
phase of the validation studies led to
certain recommendations about specific
VOST procedures to be followed during
field testing. An estimate of recovery
(accuracy) and precision for the VOST
Protocol under field conditions is also
described.
Laboratory Validation Studies
Experimental
Six volatile organic compounds were
selected for use in the VOST laboratory
evaluation. These compounds are listed
in Table 1. This table shows the boiling
points and incinerability of the com-
pounds. Two of these compounds, carbon
tetrachloride and chloroform, were in-
cluded because of their expected frequent
designation as POHCs in hazardous waste
incinerator trial burns. Benzene was in-
cluded because of the effect its historically
high background levels has had on Tenax,
which is the primary sample collection
medium of the VOST. Tetrachloethylene
(TCE) was included in the study to test
recovery of a compound with a boiling
point (121 °C) near the high range of the
protocol (approximately 100°C). Trichloro-
fluoromethane (TCFM) was selected be-
cause its low boiling point (24°C)
challenged the recovery of the VOST near
its low range (approximately 30°C). The
final compound studied in this investiga-
tion was vinyl chloride (VC). VC was
included even though its boiling point
(-12°C) made it unlikely to be quantita-
tively recovered by the VOST. Except for
TCFM, mixtures of these compounds at
the ppb level were readily available as
Group 1 gases through the Quality As-
surance Division's (QAD) gas cylinder
audit development program (6). The
QAD's Group 1 gases were developed
and certified by the National Bureau of
Standards (NBS) and, therefore, concen-
trations of these mixtures could be traced
to NBS for use in determining VOST
recovery. A separate cylinder containing
only TCFM and nitrogen was obtained,
and the concentration of this cylinder
was similarly traced to an NBS standard.
Test gas atmospheres for the laboratory
study were generated by mixing in a
dilution system gases from a cylinder of
the five Group 1 gases (approximately 75
ppb each component, balance nitrogen).
Tab/o 1. List of Compounds Selected For VOST Protocol Validation
Incinerability*
Boiling ranking
pointb T
Compound °C A//c 799.99/2° Comments
Tetrachloroethylene
Benzene
Carbon tetrachloride
Chloroform
121 15 1
80 282 23
77
61 10 44
Trichlorofluoromethane 24 1 NL
Vinyl chloride
-12 58 26
Group 1 compound* potential
recovery problem
Group 1; historical Tenax
blank problem
Group 1; frequently selected
as a POHC
Group 1; common lab solvent.
Lower limit of acceptable
boiling point range
Group 1; potential break-
through problem
* A ranking of 1 is the most difficult to incinerate.
The general target range in the VOST Protocol is 30° to 100°C.
c Based on the heat of combustion table for 283 RCPA Appendix VIII constituents.
Based on the temperature required to achieve 99.99 percent destruction at a residence time of
two seconds (list of 55 compounds compiled by J. J. Cudahy of IT Enviroscience. September
1983).
e Group number refers to the QAD gas cylinder audit program.
' A/~« i;»««~i
Not listed.
a cylinder of approximately 75 ppb TCFM
in nitrogen, and a cylinder of ultra-pure
zero air. Test gas concentrations of ap-
proximately 15 and 0.5 ppb were gener-
ated. These two concentrations were
considered to be within the range of
normal hazardous waste incinerator
POHC concentrations.
A quad (four-train) VOST was used to
collect four samples simultaneously from
a manifold purged with test gas of known
levels of target compounds. Figure 1
shows a schematic of the quad VOST
equipment in the laboratory evaluation.
Figure 2 shows a more detailed descrip-
tion of a single VOST. Two types of VOST
sample collection tubes are specified in
the VOST Protocol. Figure 3 shows the
two tube configurations in detail. The
term "ST" is used here to designate the
suspended tube design. This tube is con-
ventionally used in ambient air sampling
with Tenax. The other design is designated
"ND" for neck-down tube. The VOST
Protocol defines the ND as the inside/
inside tube configuration and the ST as
the inside/outside tube configuration.
Since one of the goals was to determine
which design to use in field work, the
quad VOST laboratory experiments were
conducted with two ST-type trains and
two ND-type trains.
The sorbent traps were all prepared
from one lot of Tenax and one lot of
charcoal and were prepared and condi-
tioned as specified in the protocol. Pre-
paration and conditioning of the traps
were performed in a separate area of the
laboratory in which no solvents are
handled or stored. The exact handling of
each trap during preparation and condi-
tioning activities was documented in a
log book.
All sorbent traps were analyzed in the
same manner and in accordance with the
protocol. Each sampled trap was spiked
with an internal standard, thermally
desorbed with organic-free helium gas
bubbled through organic-free water and
collected on an analytical sorbent trap.
After the sample desorption steps, the
analytical sorbent trap was rapidly heated
and the carrier gas flow was reversed so
that the effluent flow from the analytical
trap was directed into the GC/MS. The
volatile organics were separated by
temperature-programmed gas chromato-
graphy and detected by low-resolution
mass spectrometry. The mass of volatile
compounds was calculated by the internal
standard technique.
Unless specifically designated other-
wise, all samples were analyzed within
one week of collection.
Results and Conclusions
In the course of performing the labora-
tory evaluation, several parameters were
-------
Set up for Moisture Runs
Caps
Teflon 4-Port
Manifold
X
/
Teflon Tubine
Ultra-Pure
Zero Air
X
~ 70 ppb
Group 1
Compounds
o o o
Dilution System
with Glass
Mixing Chamber
Apparatus
Wrapped with
Heat Tape
-&
Purge/Leak
Check Pump
1
o
1
o
f
o
f
0
~ 90 ppb
TCFM
Four Meter Control Units
Figure 1. Schematic of sampling arrangement for laboratory evaluation.
studied (sorbent tube design, moisture
level in the sample gas, and sample hold-
ing time).
The effects of tube design and mois-
ture level varied from one component to
the next. The following discussion
describes the individual component data
presented in Table 2, which was sum-
marized from eight quad VOST runs.
The sample means are simple averages
of paired run data; standard deviation are
pooled from paired run data. The percent
relative standard deviation (RSD) values
represent the pooled standard deviations
expressed as a percent of the means. The
percent expected value (EV) is the mean
measured concentration expressed as a
percent of the concentration of the target
compound in the sampled gas stream.
The statistical significance of the dif-
ference between the paired measurement
results for each type of sampling train
was determined by analysis of variance
(ANOVA) for the dry test runs. The
statistical significance of any difference
between train types for the wet runs was
determined by use of the t-test. Differ-
ences between train-types were deter-
mined to be statistically significant if the
respective test indicated less than a 10
percent probability that the difference
was due to chance.
All samples for quad Runs Q1, Q2, and
Q3 were analyzed in the laboratory within
less than one week after sample collec-
tion. Samples from quad Run Q4 were
analyzed two weeks after sample collec-
tion and those from quad Run Q5 were
analyzed five weeks after collection. These
data are shown in Table 3. All of these
samples were collected during the same
week of sampling and at the same
nominal test conditions, 15-ppb concen-
tration of target compounds in a dry gas
stream. The measured concentration data
were analyzed statistically by ANOVA to
determine if the difference between re-
sults obtained at the three sample holding
times was significant. For example, the
average concentration of VC for Run Q5
(five-week holding time) was compared
with the average concentration of VC for
Run Q4 (two-week holding time) and for
Runs Q1, Q2, and Q3 (holding time less
than one week). If the difference between
the concentration was significant, the
effect of holding time was significant.
There was an overall tendency toward
a decrease in the reported concentration
of each target compound as the time
between sample collection and sample
analysis was increased. The value ob-
tained for any compound on either type
of trap, except VC on ST traps, was the
highest when analysis was completed
within one week. This apparent effect of
-------
Probe
Liner
Connection
4-Way
Teflon Valve
To Leak Check Apparatus
To Purge System
Digital
Temperature
Indicator
Tenax/
Charcoal
Trap
Cooling
Water
Pump
500-ml
Condensate Flasks
1 Ice Water Bath
\ Thermometer
Dr*Gas] Control
Meter Valve
i Leak-Free
Pump
Note: Condenser/Trap/Flask Joints are in Two Configurations. One lor
Necked-Down Tube Traps and One for Suspended-Tube Traps.
Meter Control Unit
Figure 2. Schematic of single volatile organic sampling train (VOST).
sample holding time was statistically
significant for VC and TCFM, the two
lowest-boiling compounds studied.
The results of these laboratory tests
indicate that the VOST precision and
component percent recovery depend on
the target compound and on the type of
sorbent trap used. In some cases, the
precision and percent recovery may also
be affected by the moisture content of
the sample stream and the amount of
compound collected on the sorbent trap,
which is a function of the concentration
in the sample stream, the sampling rate,
the sample volume, and the sampling
time.
The precision and accuracy for the ND
and the ST types of sorbent traps varied
in certain cases. For example, of the
three compounds, chloroform, carbon
tetrachloride, and TCE, only carbon
tetrachloride showed differences in preci-
sion and percent recovery between the
ND and ST traps. For carbon tetrachloride,
the ST traps also showed percent recovery
differences between wet and dry condi-
tions. The precision reflected by the
pooled relative standard deviation of the
replicate pairs ranged between 10 and
20 percent and also indicated that the ND
traps were superior to the ST traps.
Held Test Validation Studies
Experimental
The Phase II field test validation of the
VOST Protocol was conducted at the
hazardous waste incinerator operated at
EPA's Combustion Research Facility (CRF)
near Jefferson, Arkansas. This incinerator
is a pilot-scale rotary kiln type with an
afterburner and caustic scrubber for
emission control. Figure 4 shows a
schematic of the sample point location in
the process. The primary purpose of the
validation was to determine the expected
precision and accuracy of the protocol at
a hazardous waste incinerator for certain
specific POHCs. The POHCs for the field
study were the same as in the laboratory
study except vinyl chloride was not in-
cluded because of its poor recovery. A
series of VOST runs was conducted on
the incinerator stack gas with a four-train
(quad) sampling assembly. Each quad run
consisted of four samples collected
simultaneously at the same point in the
gas stream. A portion of the stack gas
was spiked with the desired amount of
target compounds by using mass flow
controllers and a compressed gas cylinder
containing approximately 150 ng/liter of
each target compound. The amount of
spike gas used for the tests represented
less than 10 percent of the sample
volume. All samples were collected at
the nominal protocol conditions of 1
liter/minute for 20 minutes. Spike levels
provided a minimum of 200 ng of each
target compound (approximately 1-5 ppb
concentration of target compound).
For recovery determinations, eight test
runs were made with the quad sampling
train. Figure 5 shows a schematic of the
recovery test equipment in which two of
the trains in each quad run were spiked
individually. The other two trains in each
quad run were not spiked so that back-
4
-------
Tenax or Tenax/Charcoal Tube
(Wcmx 1.6 cm Glass) Holds
Approximately 2 grams Sorbent
Glass Cap
Viton 0-Ring Joint
Vitton O-Ring Between
Tenax Tube O.D. and Trap 1.D.
Tenax or Tenax/Charcoal Tube
(Wcmx 1.6 cm Glass)Holds
Approximately 2 grams Sorbent
120 mesh Stainless Steel Screen
Zinc-Coated Steel Internal
Retaining Ring ("C-Clip")
Viton 0-Ring
Viton 0-Ring Joint
Glass Cap
Tube
Length
~ 5 in.
Suspended-Tube (ST)
Figure 3. Sorbent trap configurations.
Glass Wool
'/4-in. Swage/ok 316-SS
Nut and Cap
(SupeltexM-1 Ferrules)
Necked-Down (NO)
ground levels could be measured. The
average background level of each target
compound in the two unspiked samples
was used to correct the amount of target
compounds detected in each of the spiked
samples. The amount of the target com-
pounds recovered from the spiked trains
(corrected for background) was used to
estimate the level of recovery (accuracy)
obtained by the VOST Protocol during the
test series.
For precision estimates, seven test runs
were made with the quad sampling train.
Figure 6 shows a schematic of the preci-
sion test equipment in which a portion of
the stack gas was extracted from the duct
and spiked with the desired amount of
target compounds so that all four trains
in a given quad run were exposed to the
same concentration of target compounds.
Overall, VOST precision was estimated
by pooling the relative standard deviations
of the seven quad runs.
The 15 quad VOST runs were made
during three separate field trips. During
each trip, tests were conducted while the
incinerator was burning commercially
available solvents (all of which were listed
in the Resource Conservation and Re-
covery Act (RCRA) Appendix VIII) but none
of the target compounds. This was done
to minimize the background level of target
compounds in the stack gas compared
with the 200-ng spiking level. Two of the
recovery runs (Runs 4 and 5) were made
with 1,2-dichloroethane (DCE) as the feed
solvent. All of the other tests were made
with a feed solvent mixture referred to as
Soup 2. This mixture consists of approxi-
mately 28 percent by weight each of
nitrobenzene, 1,2,4-trichlorobenzene, and
acetonitrile, and the balance made up by
toluene. Propane was fired as an auxiliary
fuel to maintain system temperatures.
All sampling times were 20 minutes,
and between 20.1 and 21.3 liters were
collected during each run (at metered
conditions). These conditions corre-
sponded to average sampling rates
between 1.00 and 1.06 liters/min. The
gas temperature at the exit of the primary
condenser averaged between 5.6° and
19.7°C, and the maximum temperatures
were all less than 20°C.
All sample preparation, conditioning,
and analysis procedures were in accor-
dance with the February 1984 VOST
Protocol and the minor modificiations as
recommended by the results of Phase I.
To eliminate any problems associated with
sample holding time, all samples were
analyzed within one week of the field
collection.
As a part of the field study, laboratory
blanks, trip blanks, and field blanks were
taken. Laboratory and trip blanks re-
mained sealed until analysis. Their
analysis showed less than 2 ng of any
POHC except for benzene which was
more variable, ranging up to 14 ng.
Benzene has been reported as an in-
herent contaminant in the Tenax sorbent.
The recommended procedure for taking
field blanks is to install them in the
sampling train during the leak check
procedure. This ensures that the blanks
are exposed in the same manner as the
actual sample tubes. Only chloroform was
found in significant quantities in the field
blanks during the first field test. During
this test high levels of chloroform were
-------
Table 2. Summary of Precision, Accuracy, and Train-Type Comparison Results8
Nominal test
conditions
0.5 ppb, dry*
Parameter
Trap type
X, ng/ liter
ac. ng/liter
%RSDC
%EVd
Vinyl
chloride
ND
0.60
0.09
15.0
42
ST
0.17
0.01
5.9
12
Trichloro-
fluoro-
methane
ND
2.22
0.31
13.9
78
ST
2.37
1.42
55.9
83
Chloroform
ND
1.90
0.08
4.2
83
ST
1.94
0.11
5.7
85
Carbon
tetra-
chloride
ND
2.72
0.14
5.1
85
ST
2.28
0.26
11.4
71
Benzene
ND
2.87
1.04
36.2
175
ST
2.55
1.13
44.3
155
Tetrachloro-
ethylene
ND
3.69
0.03
0.8
103
ST
3.91
1.79
45.8
109
Significant
difference?8
0.5 ppb, wet'
Significant
difference?9
15ppb,dryh
Significant
difference?8
15 ppb, wet'
Significant
difference?3
X, ng/liter
a, ng/'liter
%RSD
%EV
X, ng/liter
a , ng/liter
%RSD
%EV
X. ng/liter
a . ng/liter
%RSD
%EV
Yes
0.53 0.36
0.13 0.09
24.5 25.0
38 26
Yes
No
No
Yes
No
2.74
0.17
6.2
97
2.53
1.0
39.5
89
2.02
0.12
5.9
89
1.84
0.27
14.7
81
2.71
0.39
14.4
85
1.63 2.48
0.32 0.75
19.6 30.2
51 153
2.01
0.03
1.5
124
No
No
Yes
No
No
3.79 3.55
0.15 0.40
4.0 11.3
107 100
No
38.55 5.25 63.79 46.78 79.73 73.03 88.23 75.55 57.03 53.01 130.2 117.1
2.89 2.18 3.47 7.93 18.68 2.19 24.64 3.10 15.12 2.20 32.02 10.51
7.5 41.5 6.3 17.0 23.4 3.0 27.9 4.1 26.5 4.2 24.6 9.0
91 12 76 56 116 1O6 92 78 116 107 121 108
Yes
Yes
No
No
No
No
20.32 19.98 64.47 33.84 73.34 65.31 86.46 53.43 52.64 49.35 143.4 139.2
2.10 3.71
10.3 18.6
48 47
No
4.55 6.62
7.1 19.6
75 39
Yes
2.89
3.9
107
6.12
9.4
95
Yes
1.13 2.39
1.3 4.5
90 56
Yes
1.10
2.1
107
3.45
7.0
too
No
4.16 3.51
2.9 2.5
133 129
No
8 Includes data from quad Runs Q1 through Q3 and Q6 through 08 and paired Runs W1 through W8. No data are corrected for blank values.
b Quad Runs 06 through Q8, including all data except Run Q7, Sample No. L.5ST112 values for all compounds.
0 Standard and relative standard deviations are pooled from paired run data.
Percent of expected value = (X/EV)x 100, where EVis the average for applicable runs taken from the summary table of dilution system data and
expected concentrations in ng/liter.
e Difference between train types based on analysis of variance at 10% probability level.
Paired Runs W5 through W8, including all data. The moisture content of the sampled gas stream was approximately 30%.
9 Based on t-test statistic at 10% probability level, difference between train types.
. Quad Runs Q1 through Q3, including all data except Run 02, Sample No. L15ND321 values for vinyl chloride and trichlorofluoromethane.
1 Paired Runs W1 through W4, including all data. The moisture content of the sampled gas stream was approximately 30%.
present in the gas stream. During the
following two tests no high POHC levels
were found in the field blanks. The use of
field blanks is recommended as a way of
identifying possible contamination
problems.
The sampling train also collects a
condensate fraction. Since the POHCs
chosen for this evaluation were not
especially water soluble, several runs of
condensate were grouped together for
analysis. These composite samples
showed less than one percent of the
POHC compounds present in the
condensate.
Results and Conclusions
Precision of the VOST method was
determined by calculating the pooled rela-
tive standard deviation from the valid
quad runs as described in the experi-
mental section. As shown in Table 4,
results for certain of the target com-
pounds were invalidated in some of the
samples. Precision run 6 (Run P6) was
voided because the final dry gas meter
readings were not recorded properly.
Sample P1 -4 (Precision Run 1, Train 4)
was voided because the end of Tenax/
charcoal trap was broken and it could not
be connected to the analytical system in
the normal manner. One of the sorbent
traps in sample P3-4 and in sample P5-3
was broken in the field, and these samples
were not analyzed. The internal standards
were loaded improperly for sample P4-4.
The GC/MS filament was flickering
throughout the analysis of sample P8-3.
None of these results were used in the
precision calculations.
The remaining data yielded sufficient
information about precision of the VOST
method. Table 4 also shows the calculated
percent relative standard deviation
(%RSD) for each of the test components.
These %RSD data show that the VOST
method is capable of attaining precision
estimates of less than 5%. These are
levels much better than expected and not
attained in other tests where process and
POHC component quality control may not
be possible.
Accuracy of the VOST method was
defined by the percent recovery of the
spike compounds. The spiking procedure
is described in the experimental section.
-------
holding
timeb
(weeks)
1°
2e
Parameter
Trap type
X ng/ liter
ad, ng/ liter
%RSDd
X. ng/ liter
o, ng/ liter
%RSD
Vinyl
Chloride
ND
38.55
2.89
7.5
15.21
2.11
13.9
ST
5.25
2.18
41.5
7.28
0.23
3.2
Trichloro-
fluoromethane
ND ST
63.79 46.78
3.47 7.93
6.3 17.0
47.56 31.16
4.29 2.25
9.0 7.2
Chloroform
ND
79.73
18.68
23.4
70.72
0.76
1.1
ST
73.03
2.19
3.0
67.74
9.19
13.6
Caruon
tetrachloride
ND
88.23
24.64
27.9
75.55
0.38
0.5
ST
75.55
3.10
4.1
72.33
6.29
8.7
Benzene
ND
57.O3
15.12
26.5
53.04
3.31
6.2
ST
53.01
2.20
4.2
47.80
2.65
5.5
Tetrachloro-
ethylene
ND ST
130.2 117.1
32.02 10.5
24.6 9.0
116.0 99.5
2.19 7.50
1.9 7.5
Difference.
39
-33 -11
-14
-7
-1O -11
-15
X. ng/'liter
a. ng/liter
%RSD
10.70 6.42 50.02 29.60 70.42 68.26 81.86 70.29 50.68 50.20 126.1 112.2
5.64 5.03 0.40 4.64 6.02 5.20 3.09 3.27 1.28 1.02 20.93 12.30
52.7 78.3 0.8 15.7 8.5 7.6 3.8 4.7 2.5 2.0 16.6 11.0
Difference, %
-72
22
-22
-37 -12
-7
-7
-7
-11
-5
-3
-4
Significant.
difference^1
Yes1
Yes
No
No
No
8 All samples collected at a nominal target compound concentration of 15 ppb in a dry gas stream. AH data were used from Runs Q1 tht
except for Run Q2, Sample No. L15ND121 values for vinyl chloride and trichlorofluoromethane. No data are corrected for blank values.
b Time between sample collection and analysis. All samples were stored in refrigerated cans containing charcoal.
c Runs Q1 through Q3.
Standard and relative standard deviations are pooled from paired run data.
8 Run Q4.
Difference between mean concentrations at indicated holding time and initial values,
% = Xi-X initial x 1QQ
a „ __ X initial
y Run OS.
h. Difference between holding times based on analysis of variance at 10% probability.
' The effect of sample holding time is significant for the ND train but not for the ST train.
No
All recovery tests were made when the
incinerator was burning the compound
mix described as Soup 2 except for Runs
4 and 5 which were made during the
incineration of DCE. The tests (DCE only)
showed high amounts of chloroform (640
to 965 ng) and carbon tetrachloride (65 to
212 ng) in the unspiked samples relative
to the amounts in the spiked samples
(approximately 200 ng). Otherwise (using
Soup 2), the amounts of target compounds
detected in the unspiked background
samples were less than approximately
50 ng. Values for TCFM were generally
less than 12 ng. Values for TCE were
generally less than 9 ng. Values for
chloroform, carbon tetrachloride, and
benzene generally ranged between 15
and 50 ng. The amounts detected in the
spiked samples ranged between 180 and
354 ng.
As shown in Table 5, the results of
certain target compounds were invali-
dated for some of the samples, and for
specific target compounds in others.
Sample R4-3-US (Run 4, Train 3, Un-
spiked) was voided because one of the
sorbent traps was broken after the internal
standard was loaded. Results for sample
R5-4-US were not used because the
Tenax/charcoal trap was connected
backward during analysis. The results for
chloroform in sample R1 -3-S and results
for TCFM in sample R5-3-S were voided
because the mass spectrometer detector
was interrupted during integration of
these peaks. Recovery values for R4 and
R5 for chloroform and carbon tetra-
chloride were voided because of the high
background level relative to the spike
amounts as described earlier.
The average of the two unspiked
samples was used as a measure of the
component background levels. Because
the other two sampling trains were spiked
separately, they are treated as indepen-
dent samples and provide two indepen-
dent estimates of sample recovery. The
mean recovery is reported as a
percentage.
Table 5 also shows the calculated
average recoveries (X) and standard
deviation (SD) of the POHCs. The average
recovery was higher than 90%, with two
components (chloroform and TCE) show-
ing a positive bias of approximately 20%.
However, as a general conclusion both
the laboratory and field data show that
the VOST when carefully applied is cap-
able of providing both precise and ac-
curate measurements of volatile organics
found at low parts-per-billion gas
concentration.
References
1. Code of Federal Regulations, Title 40,
Part 264 (1980).
2. Harris, J. C., et al., "Sampling and
Analysis Methods for Hazardous
Waste Combustion," EPA 600/8-84-
002, February 1984.
3. Hansen, E. M., "Protocol for the Col-
lection and Analysis of Volatile POHCs
Using VOST," EPA 600/8-84-007,
March 1984.
4. Validation of the Volatile Organic
Sampling Train (VOST) Protocol -
Laboratory Phase, EPA.
5. Validation of the Volatile Organic
Sampling Train (VOST) Protocol - Field
Validation Phase, EPA.
-------
Gas Flow from
Liquid Injection
Incinerator System
"E" Location
Sample Platform
Area for Quad
VOST Sampling
Port A |
~6ft
J
T
Carbon
Bed
Hepa
Filter
9ft
I.D. Fan and Final
Exit Stack
/.£». fan
ffmgmmmggmtgm
Gas f/ow from Scrubber on Rotary Kiln Incinerator
Plan View
14'/2-in.-i.d. Insulated Duct
2-in.
Diameter
Ports
~3ft
Sample
Platform
10ft
Ground
Section A-A
Figure 4. Schematic of "E" location sampling site at CRF.
6. Jayanty, R. K. M., et al., "Evaluation of
Parts-per-billion Organic Cylinder
Gases for Use as Audits During Haz-
ardous Waste Trial Burn Tests," APCA
35 No. 11, November 1985.
8
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Glass
Wool
Plug
Stack
Gas
To Leak
Check
Train 4-Way Valves
Charcoal
\*iiati,vai *
3-Way ^
__Valves fzsfy
Train 4
Train 3
Common.
Heated.
Glass -Lined
Probe
Tnfcal^i Extended
Area Heated
Train 1
To Leak
Check
To Control
Modules
Quad VOST Sample Box
_^ 0 fo 1 00 ml/ mi n Mass
j Flow Controllers
Spike Gas
Cylinder
Figure 5.
Schematic of sampling trains and spiking apparatus for recovery (accuracy) quad
runs.
-------
Heated, 316
Stainless -
Steel-Lined
Probe
Sections
Glass WooL
Plug
hnnnjl •
itiC
Method 4
Type Iminger
Train
Train 4- Way Val\
^^»-_— ______.. _~»
Common,
Heated.
Glass-Lined
Probe
-Orifice Plate
/ for Mixing K
Charcoal
To Meter
• Control
Module
tilica Gel/Charcoal
£ To Leak
£. * Check
•***> _ , ,,. „.
<&l
^^ frl Train 3 \
-CjJJ
g> To Leak
£ Check
Quad I/OS 7" Sample Box
Modules
Vent for Bubble 0 to 1 liter/min Mass
Meter Flow Check Flow Controller
Readout
Box
Spike Gas
Cylinder
*- Stack Gas
Figure 6. Schematic of sampling trains and spiking apparatus for precision quad runs.
10
-------
Tiib/e 4. Summary Results of Each Precision Run
Precision Test Number
Value
P-1
P-2
P-3
P-4
P-5 P-6
P-7
P-8
Summary Results
POHC = Trichlorofluoromethane
n
X(ng/1)
SD (ng/1)
RSD (percent)
POHC - Chloroform
n
Xfng/IJ
SD(ng/1)
RSD (percent)
POHC = Carbon tetrachloride
n
X(ng/1)
SD Ing/1)
RSD (percent)
POHC = Benzene
n
X(ng/1)
SD(ng/1)
RSD (percent)
POHC = Tetrachloroethylene
n
X(ng/1)
RSD (percent)
3
= 14.82
= 0.77
= 5.19
3
= 17.68
= 0.32
1.78
3
= 20.16
0.78
3.87
3
= 19.99
0.18
0.91
3
= 79.55
3.82
4
16.55
0.66
4.02
4
18.68
0.44
2.34
4
20.74
0.57
2.75
4
20.03
0.34
1.68
4
21.51
4.86
3
16.18
0.45
2.76
3
18.06
0.62
3.44
3
21.46
0.58
2.69
3
19.56
0.78
4.00
3
19.89
3.32
3
17.50
0.18
1.01
3
20.04
0.54
2.70
3
22.36
0.85
3.82
3
21.65
0.69
3.18
3
22.60
5.29
3 —
14.36 —
0.64 —
4.48 -
3 —
15.42 —
0.39 —
2.52 —
3 -
17.62 —
0.71 —
4.04 —
3 —
15.10 —
0.17 -
1.09 -
3 —
17.20 —
3.61 —
4
10.01
0.58
5.78
4
12.35
0.47
3.77
4
11.07
0.25
2.22
4
13.56
0.57
4.18
4
13.68
2.61
3
10.56
0.97
9.18
3
13.56
0.60
4.45
3
11.61
0.51
4.37
3
14.30
0.24
1.71
3
0.8 ng/1
2.97
n
X
SD
RSD
n
X
SD
RSD
n
X
SD
RSD
n
X
SD
RSD
n
RSD
= 23
= 14.1 ng/1
= 0.7 ng/1
= 4.6%
= 23
= 16.4 ng/1
= 0.4 ng/1
= 3.0%
= 23
= 17.7 ng/1
= 0.6 ng/1
= 3.5%
= 23
= 17.7 ng/1
= 0.5 ng/1
= 2.7%
= 23
= 4.1%
Table 5. Summary Results of Each Recovery Run
Recovery Test Number
Value
POHC =
1 =
2 =
X =
POHC =
1 =
2 =
X =
POHC =
1 =
2 =
X =
POHC =
1 =
2 =
X =
POHC =
1 =
2 =
X =
R-1
R-2
R-3
Trichlorofluoromethane
89.45
1 05.63
97.54
Chloroform
126.31
126.31
98.66
89.96
94.31
127.81
129.27
125.54
91.83
94.56
93.20
1 10.98
116.68
1 13.83
R-4
R-5
R-6
R-7
R-8
Summary Results
Percent Recovered
100.62
108.17
104.39
—
90.75
90.75
—
85.41
90.67
88.04
131.94
132.18
132.06
79.26
75.14
77.20
116.08
133.26
124.67
86.33
109.21
97.77
121.36
156.78
139.07
n =
X =
SD =
n =
X =
SD =
15
93%
10%
11
127%
12%
Carbon tetrachloride
106.06
108.79
107.43
Benzene
100.07
1 10.54
105.30
11O.64
120.59
1 15.62
114.73
104.07
109.40
104.26
105.86
105.06
99.56
100.53
100.04
—
103.90
108.20
106.05
—
103.84
109.65
106.74
103.87
99.82
101.84
112.75
117.74
115.25
94.32
1 19.24
106.78
98.20
1 15.20
106.70
102.52
115.14
108.83
109.15
104.35
106.75
n =
X =
SD =
n =
X =
SD =
12
108%
8%
16
107%
6%
Tetrachloroethylene
107.84
114.82
1 1 1.33
123.35
115.25
119.30
110.80
127.28
1 19.04
124.00
131.12
127.56
114.55
125.84
120.20
125.90
134. 16
130.03
1 19.36
132.45
125.90
125.65
122.20
123.92
n =
X =
SD =
16
122%
8%
11
U. S. GOVERNMENT PRINTING Of FKE: 1986/646-116/20804
-------
The EPA authors, Thomas J. Logan, Robert G. Fuerst (also the EPA Project
Officer, see below), and M. Rodney Midgett are with Environmental
Monitoring Systems Laboratory, Research Triangle Park, NC 27711; John
Prohaska is with PEI Associates, Inc., Cincinnati. OH 45246.
The complete report, entitled "Validation of the Volatile Organic Sampling Train
(VOST) Protocol," consists of two volumes:
"Volume I. Laboratory Validation Phase," (Order No. PB 86-145 547'/AS;
Cost: $22.95. subject to change).
Volume II. Field Validation Phase," (Order No. PB 86-145 554/AS; Cost:
$28.95, subject to change).
The above reports 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, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S4-86/014
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