SEPA
United States
Environmental Protection
Agency
Environmental Monitoring and Support EPA-600/4-80-003
Laboratory January 1980
Research Triangle Park NC 27711
Research and Development
Evaluation of
Emission Test
Methods for
Halogenated
Hydrocarbons
Volume I
CH.CL, CHaCCIs,
CF.CICFCh, and
CH.BrCH.Br
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EVALUATION OF EMISSION TEST METHODS FOR HALOGENATED HYDROCARBONS
VOLUME II:
CH3CC13, CF2C1CFC12, AND
by
Joseph E. Knoll, Mark A. Smith, and M. Rodney Midgett
Quality Assurance Division
Environmental Monitoring Systems Laboratory
Research Triangle Park, North Carolina 27711
ENVIRONMENTAL MONITORING SYSTEMS LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring Systems
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
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FOREWORD
Measurement and monitoring research efforts are designed to anticipate
potential environmental problems, to support regulatory actions by developing
an in-depth understanding of the nature and processes that impact health
and the ecology, to provide innovative means of monitoring compliance with
regulations, and to evaluate the effectiveness of health and environmental
protection efforts through the monitoring of long-term trends. The Environ-
mental Monitoring Systems Laboratory, Research Triangle Park, North Carolina,
has responsibility for: assessment of environmental monitoring technology
and systems; implementation of agency-wide quality assurance programs for air
pollution measurement systems; and supplying technical support to other groups
in the Agency including the Office of Air, Noise and Radiation, the Office of
Toxic Substances and the Office of Enforcement.
The following investigation was conducted at the request of the Office
of Air Quality Planning and Standards. A test method for the measurement of
halogenated hydrocarbon emissions from stationary sources was evaluated. The
work included a study of integrated bag sampling techniques and methods of
gas chromatographic measurement. Some information was also obtained on the
stability of halogenated hydrocarbons in compressed gas mixtures. Volume I of
this series dealt with carbon tetrachloride, ethylene dichloride, tetrachloro-
ethylene, and trichloroethylene. In the present study, the applicability of
this test method for the analysis of ethylene dibromide, Freon 113, methyl
chloroform, and methylene chloride was evaluated.
Thomas R. Hauser, Ph.D.
Director
Environmental Monitoring Systems Laboratory
Research Triangle Park, North Carolina 27711
m
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ABSTRACT
The techniques used in a source test method for halogenated hydrocarbons
were evaluated. Cylinder gases used for calibration and auditing were tested
for stability. Decreases in concentration of 3-4% per month were observed for
Freon 113, methyl chloroform, and methylene chloride. Tedlar and aluminized
Mylar bags used in integrated sampling were also studied. In general, Tedlar
bags were found to be superior, maintaining Freon 113 samples stable for 10
days, methyl chloroform for 7 days, methylene chloride for 6 days and ethylene
dibromide for 2 days, at room temperature. Heated ethylene dibromide samples,
however, were more stable in aluminized Mylar than in Tedlar. The chromato-
graphic column specified in the test method was also evaluated. It resolved
all of the compounds of interest, with the exception of ethylene dibromide.
A suitable column is recommended for that substance.
IV
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CONTENTS
Foreword iii
Abstract iv
Tables vi
Figure vi
Abbreviations and Symbols ..... vii
Acknowledgment viii
1. Introduction 1
2. Conclusions .................. 3
3. Experimental ...... ..... 5
4. Results and Discussion 8
Stability of halogenated hydrocarbon gas mixtures
in aluminum cylinders 8
Stability of halogenated hydrocarbon samples in Tedlar
and aluminized Mylar bags at ambient temperatures .... 9
Stability of halogenated hydrocarbon samples in Tedlar and
aluminized Mylar bags at temperatures above ambient ... 11
Memory effects resulting from high concentrations ...... 12
Separation of halogenated hydrocarbons by gas
chromatography 12
References 14
Appendix
A. Method for the determination of halogenated organics
from stationary sources . 22
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TABLES
Number Page
1 Time Variation of Concentrations of Halogenated Hydrocarbons
in Aluminum Cylinders 15
2 Variation of CH-CC1., Concentration of Gas Mixtures Stored in
Tedlar Bags at Ambient Temperatures , . . 16
3 Variation of CH^Clp Concentration of Gas Mixtures Stored in
Tedlar Bags at Ambient Temperatures 17
4 Variation of CF,,C1CFC12 Concentration of Gas Mixtures Stored in
Tedlar Bags at Ambient Temperatures 18
5 Variation of QOrCFLBr Concentration of Gas Mixtures Stored in
Tedlar Bags at Ambient Temperatures 18
6 Variation of Halogenated Hydrocarbon Concentrations of Gas
Mixtures Stored in Aluminized Mylar Bags at Ambient
Temperatures 19
7 Effect of Temperature on Halogenated Hydrocarbon Concentrations
of Gas Mixtures Stored in Aluminized Mylar and Tedlar Bags ... 19
8 "Memory" Effects in Tedlar Bags Resulting from High
Concentrations of Halogenated Hydrocarbons 20
9 Kovats Retention Indices of Selected Halogenated Hydrocarbons
on Various Chromatographic Columns 20
FIGURE
1 Decay of ethylene bromide stored in Tedlar bags at ambient
temperature 21
VI
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LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
°C -- degree Celsius
EPA -- U.S. Environmental Protection Agency
ft -- foot
hr -- hour
i.d. -- inside diameter
in -- inch
yl -- microliter
ml -- milliliter
min -- minute
OAQPS -- Office of Air Quality Planning and Standards
o.d. -- outside diameter
ppm -- part per million
SYMBOLS
CH2C12 -- methylene chloride
ChLCCl, -- methyl chloroform
CF2C1CFC12 -- Freon 113
ChLBrChLBr -- ethylene dibromide
N? -- nitrogen
VI 1
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ACKNOWLEDGMENTS
The authors thank Mr. K. Wi-lliam Grimley and his colleagues in the
Emission Measurement Branch, Emission Standard and Engineering Division, for
permission to include their Method for the Determination of Halogenated
Hydrocarbons from Stationary Sources in the appendix of this report, and for
many helpful discussions.
vm
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SECTION 1
INTRODUCTION
Volume I of this series reported on the evaluation of source test
methods for carbon tetrachloride, ethylene dichloride, tetrachloroethylene,
and trichloroethylene (1). These substances have been selected by the U.S.
Environmental Protection Agency (EPA) as compounds for which human exposure
must be limited (2). The source test method under consideration, EPA tenta-
tive Method 23, was formulated in the Emission Measurement Branch, Emission
Standard and Engineering Division, Office of Air Quality Planning and
Standards (OAQPS) (see Appendix A).
The present study was undertaken to evaluate the applicability of
Method 23 for the analysis of methylene chloride (CHLC1-), methyl chloroform
(CH3CC13), Freon 113 (CF2C1CFC12), and ethylene dibromide (CH2BrCH2Br). The
first three of these compounds are employed as industrial solvents, while the
fourth is an important chemical intermediate. The tentative method under
consideration employs Tedlar or aluminized Mylar bags for sample collection
and gas chromatography with flame ionization detection for analysis. The use
of bottled gas mixtures is one calibration option.
Every sampling method should employ a container that preserves the
sample free from contamination and change. Tedlar bags have been successfully-
employed for this purpose in the source sampling methods for vinyl chloride (3)
and for benzene (4). Recent work on the use of plastic containers for source
sampling methods are reviewed in Volume I of this study (1). The present
investigation was carried out to obtain information on the stability of gas
mixtures containing CH2C12, CH3CC13, CF2C1CFC12, and CH2BrCH2Br in Tedlar and
aluminized Mylar bags. Some information was also obtained on the efficacy of
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compressed gas mixtures for use as secondary standards during field measure-
ments as well as on chromatographic columns for resolution of the compounds
of interest.
The work for this study was carried out in the Source Branch of the
Quality Assurance Division, Environmental Monitoring Systems Laboratory,
Research Triangle Park, North Carolina; this laboratory has a program to
evaluate and standardize source emission test methodology.
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SECTION 2
CONCLUSIONS
Aluminum cylinders containing ChLCCl.,, ChLCl?, and CF?C1CFC12 "in nitrogen
(N2) decrease in concentration by 3-4% per month over a period of 4 months.
Tedlar bags can be used to store samples of ChLCCl,, in N2 at source-level
concentrations for at least 7 days with a decrease in concentration of less
than 10%. Tedlar bag samples of CF^CICFCI,, remain stable for at least 10 days,
CH2C12 for at least 6 days, and CH2BrCH2Br for less than 2 days.
When stored in aluminized Mylar bags, samples of ChLCl? in N? remain
stable for 4 days, CH3CC13 for 2 days, CF2C1CFC12 for 11 days, and CH2BrCH2Br
for 2 days.
Tedlar bag samples of ChLCCl.-, in air are as stable as samples in N2.
Heating to 75°C for 16 hrs causes no change in the concentration of ChLCCl,.
samples stored in Tedlar bags. The same schedule of heating causes CF2C1CFC12
and ChLClp gas samples to decrease in concentrations by 45 and 17%, respectively
Aluminized Mylar bag samples of CF2C1CFC12 remain stable when heated to
75°C for 16 hours, while samples of ChLCCl., decrease in concentration by 20%.
Residues formed in Tedlar bags due to their exposure to high concentra-
tions of CH2C12 and CF2C1CFC12 can be removed through a procedure of flushing
three times with N?, heating for one hour at 60°C, and then flushing again.
Residues of ChLCCl.,; however, cannot be removed in this manner.
The chromatographic column specified in EPA Method 23 (20% SP-2100/0.1%
Carbowax 1500 on 100/120 mesh Supelcoport in 15-ft X 1/8-in stainless steel)
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is capable of resolving CH2C12, CH3CC13, and CF2C1CFC12, but not CFLBrChLBr.
The latter compound may be resolved using a column consisting of 1,2,3-tris-
(2-cyanoethoxy)propane on 80/100 mesh Chromasorb P AW in 6-ft x 1/8-in stain^
less steel.
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SECTION 3
EXPERIMENTAL
Tedlar bags were fabricated from 2-mil plastic sheets. The edges were
sealed with a Vertrod Thermal Impulse Heat Sealing Machine (Model 48 EPS 1/4
WC). Connections to the bag were made using an 0-Seal Straight Thread Adapter
with 0.25-in o.d. tube and a 7/16-20 thread (Swagelok 401-A-OR) which was
inserted through a 2-in square piece of VisQueen polyethylene tape fixed to
the outside surface of the bag. The adapter was held in place with a 0.058-in
Teflon washer (0.5 in i.d. x 1-in o.d.) and a 7/16-20 nut. A 7115G4B Hoke
ball valve was connected to the adapter. The Tedlar bags had a volume of
approximately 100 liters. Aluminized Mylar bags were obtained from Calibrated
Instruments, Inc., (Ardsley, NY). These bags had a volume of 6 liters and
were fitted with a hose connection to which it was necessary to adapt the Hoke
valve by means of a section of Tygon tubing. In making this connection, the
length of Tygon tubing was minimized in order to reduce the contact between
the gas and the Tygon plastic.
Cylinders containing gaseous mixtures of N2 and the halogenated hydro-
carbons under investigation were obtained from Airco, Inc. (Research Triangle
Park, NC). Hydrocarbon concentrations were determined using calibration
standards prepared in Tedlar bags. These were made by injection of the liquid
compound while filling the bags with N-. The N~ was measured using a No. 802
Singer dry gas meter; a No. 801, 10-yl Hamilton syringe was used to measure
the compounds of interest. In other instances, Tedlar bags were filled
directly from the reference cylinders.
Halogenated hydrocarbon concentrations were determined using a Hewlett-
Packard Model 5930A gas chromatograph equipped with dual flame ionization
detectors and a 0.1-ml sampling loop. A Hewlett-Packard Model 18850A
integrating terminal was employed to record output. The chromatographic
5
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column consisted of a 15-ft x 1/8-in stainless steel helix packed with 20%
SP-2100/0.1% Carbowax 1500 on 100/200-mesh Supelcoport. The following
operating conditions were employed: inlet temperature, 250°C; column, 75°C;
detector, 300°C; carrier gas, liquid air N2 at 20 ml/min. Under these con-
ditions, only a single peak could be observed in each compound of interest.
The bags were sampled by drawing the gas through the chromatographic sampling
loop using a vacuum pump. Bottled gases were forced through the sampling
system under their own impetus. A benzene and a toluene gas mixture were used
to normalize the gas chromatograph results.
In several instances, gas samples containing high concentrations of the
subject compounds were introduced into Tedlar bags. These atmospheres were
prepared by slowly passing N? gas through an impinger containing the liquid
compound under study. The concentration was calculated for the saturation
vapor pressure of the halogenated hydrocarbon at 0°C, the temperature at
which the impinger was maintained. This temperature was chosen to assure
that condensation would not take place in the bag during the subsequent study.
Retention indices were determined for several halogenated hydrocarbons
and a number of other selected compounds on five chromatographic columns. The
columns were:
• Carbopak C-HT, 80/100 mesh in 6.5-ft x 1/8-in stainless steel
« 10% FFAP on 80/100 mesh acid-washed Chromasorb W in 20-ft x 1/8-in
stainless steel
• TCEP (1,2,3-tris(2-cyanoethoxy)propane on 80/100 mesh Chromasorb
P AW, 6-ft x 1/8-in stainless steel
« 20% SP-2100/0.1% Carbowax 1500 on 100/120 mesh Supelcoport in
15-ft x 1/8-in stainless steel
• 15% tetracyanoethylated pentaerythritol on 60/80 mesh Chromasorb
P AW in 16-ft x 1/8-in stainless steel
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The columns were obtained from Supelco, Inc. (Belefonte, PA) and were
conditioned overnight at a temperature and flow rate recommended by the
manufacturer. The compounds under investigation were used without further
purification.
Relative retentions in Kovats retention index units (5) were obtained
from chromatograms of suitable mixtures containing n-alkanes as internal
standards. Retention distances measured between point of injection and peak
maxima were corrected for the column gas holdup volume by means of retention
of methane (6). The adjusted retentions were then used to calculate values
for the retention index by means of the expression recommended by the Chroma-
tography Discussion Group (7):
logR - logR
I = 100 N + 100 n
1 — R— - , —
logRN+n - logRN
where R , R.., and RN+ are the adjusted retentions of the solute and n-alkanes
containing N and N+n carbon atoms, respectively.
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SECTION 4
RESULTS AND DISCUSSION
STABILITY OF HALOGENATED HYDROCARBON GAS MIXTURES IN ALUMINUM CYLINDERS
Because cylinder gases were used as calibration standards for our studies,
and also because of plans to use such cylinders in future quality assurance
programs, a study was undertaken to determine if compressed gas mixtures con-
taining the chlorinated hydrocarbons under investigation remained stable in
cylinders. A single aluminum cylinder each of ChUCCl ChLCl^, and CF2C1CFC12
were employed. In each case, the diluent gas was N2- The gases were measured
at various intervals over a period of approximately 4 months. The results are
listed in Table 1.
A stability test was carried out by performing a linear regression
analysis on each set of data and fitting it to the following equation:
Y = A + BX
where Y corresponds to concentration in ppm, X to time in days and A and B
are constants. To determine whether the slope, B, was significantly different
from zero, a "t-test" was performed. This consisted in determining a calcu-
lated t-value:
tc = (B - B)/Sb
where 3 is a hypothesized slope of zero and S, is the standard error of the
slope. The quantity tc was then compared with tabulated t-values for the
appropriate number of degrees of freedom and the 0.95 level of confidence (8).
Each of the three data sets in Table 1 show values for the ratio t /t. greater
than unity, indicating that a slope of zero can be rejected with confidence.
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The rates of change for the subject gases in Table 1 of from 3-4% per
month is too small to detect until after several months have passed. However,
the analysis given above is evidence that these decays are real. Therefore,
when cylinders of such gases are used for calibration purposes, they should be
reanalyzed after several months to determine if their concentrations have
changed.
STABILITY OF HALOGENATED HYDROCARBON SAMPLES IN TEDLAR AND ALUMINIZED MYLAR
BAGS AT AMBIENT TEMPERATURES
The stability of samples of CH3CC13, CH2C12, CH2BrCH2Br and CF2C1CFC12
in Tedlar and aluminized Mylar bags was studied. Several bag samples of each
compound were prepared by either filling the bags directly from standard
cylinders or by injecting measured amounts of liquid into bags filled with
known volumes of either N2 or air. The bags were measured over a period of
days on a Hewlett-Packard 5830 gas chromatograph and concentrations were
determined by comparison with measurements of standard cylinders.
The results of these measurements are listed in Tables 2 through 6. For
each series of data, a first order decay constant, k, was calculated along
with the quantity, t~ Q, an estimate of the time required for the sample to
decay to 90% of its initial value. This latter quantity was determined as
representative of the useful storage time of a sample. First order decay
constants were determined to compare the decay rates of the different series
of data using a simple curvilinear function. Actually, there is no evidence
that the decay processes under study were in fact first order.
The results in Table 2 show that ChLCClo has excellent stability in
Tedlar. One sample of approximately 10 ppm had a tQ g of 7 days while bag
samples in the 60-200 ppm range had tQ g values of 25 days or greater. A
bag made using air gave the same results as those using N,,. In contrast,
the results in Table 6 showed CH^Cd., to be unstable in an aluminized Mylar
bag, which had a tQ g of less than 2 days.
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Methylene chloride showed good stability in Tedlar and fair stability in
an aluminized Mylar bag. The decay rate in Tedlar was relatively independent
of concentration in the 30-200 ppm range. The storage time (tQ g) was at
least 10 days in Tedlar and 4 days in aluminized Mylar (Tables 3 and 6).
Freon 113 displayed good stability in both Tedlar and aluminized Mylar
(Tables 4 and 6). In considering this data, it should be noted that all the
concentrations studied were in the 10-20 ppm range where such good stability
is not always observed. At higher concentrations even better stability might
be expected. One bag had a storage time of 6 days, while the others were
nearly twice that. Based on these results, a permissible storage time of at
least 6 days would be indicated for CF^ClCFClp in Tedlar and in aluminized
Mylar.
In contrast, the compound ChLBrChLBr is unstable in both Tedlar and
aluminized Mylar. The data in Tables 5 and 6 indicate that such Ch^BrC^Br
samples decay to approximately 90% of their initial values in approximately
2 days. The nature of this decay is illustrated in Figure 1, which contains
a plot of the data in Table 5. First order decay lines have been fitted
through the points, and it is evident that the removal of this brominated
compound continues with time and does not reach a steady state value, making
storage of this compound risky. Consequently, the analysis of such samples
would best be carried out within a few hours of sample collection.
These results of the stability of halogenated hydrocarbons in aluminized
Mylar and Tedlar bags may be used to evaluate the maximum length of time a
sample may be retained, prior to analysis. In making such judgments, consid-
eration should be given to the concentration range in question and to the
fact that the aluminized Mylar bags were smaller than the Tedlar bags used in
this study. Smaller bags, having a greater surface to volume ratio, provide
a relatively greater degree of contact between the gaseous components and the
surface, and probably result in more rapid decay. Accordingly, the stability
tests using aluminized Mylar bags were more stringent than those carried out
in Tedlar.
10
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STABILITY OF HALOGENATED HYDROCARBON SAMPLES IN TEDLAR AND ALUMINIZED MYLAR
BAGS AT TEMPERATURES ABOVE AMBIENT
The bag stability study reported above was carried out in a 20-25°C
temperature range. However, source emissions often take place at considerably
higher temperatures; samples collected from such heated streams may expect to
remain above the 20-25°C range for a considerable time. For this reason, a
study was made of the stability of halogenated hydrocarbon gas mixtures in
aluminized Mylar and in Tedlar bags at temperatures above ambient. The tem-
perature range selected was from 70-75°C. This range was selected because
it is sufficiently high to show the effects of heating on concentration
stability, without damaging the container. Volume I of this investigation
reported the effects on concentration of temperature both above and below
ambient (1). Since at temperatures below ambient there were no observable
changes in concentration, the effects of temperatures below ambient were not
considered in the present study. However, the procedures followed were the
same as those described in Volume I. The bags were heated for the required
time period and then brought to room temperature for measurement.
One result of the heating was to cause the release of some residual
materials from the plastics. However, the amounts released were small com-
pared with the concentrations under consideration in this study. Another
result was that the seals on several of the aluminized Mylar bags opened up
when heated to 70°C, this in spite of the fact that the temperature range
had been chosen to minimize such damage. The results in Table 7 show that
CHoCClo gas mixtures were stable in Tedlar bags for 19 hrs at 70°C, but under-
O O
went a decrease in an aluminized Mylar bag at that temperature. In contrast,
CF?C1CFC1? displayed the opposite behavior — stable in aluminized Mylar but
unstable in Tedlar. Methylene chloride underwent a 17% decrease after being
heated to 75°C for 16 hours.
Certain conclusions can be drawn from these results. Heating of
aluminized Mylar bags should be avoided unless absolutely necessary. One
exception is in the collection of CF2C1CFC12 from heated sources. Tedlar is
11
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a better choice for CH3CC13. Samples of Ch^Cl,, in Tedlar bags may be exposed
to temperatures of 75°C for a few hours without significant loss.
MEMORY EFFECTS RESULTING FROM HIGH CONCENTRATIONS
A study was made of "memory" effects caused by the exposure of Tedlar
bags to very high concentrations of halogenated hydrocarbons. The amount of
residues resulting in bags subjected to high concentrations of the halogenated
compounds of interest was measured and procedures to remove them were evaluated.
To carry out this study, a high concentration gas sample was prepared for
each compound and introduced into a new Tedlar bag. After standing at room
temperature for 1 hr, the bag was flushed by evacuating it and filling it with
N2 three times. After the flushing, the concentration of the bag was measured.
The bag was then heated for 1 hr at 60°C and the concentration was remeasured.
After repeating the entire procedure, the bag was again measured. In one case,
the flushing and heating procedure was carried out a third time. The results
of the measurements are listed in Table 8.
Each bag contained residues of the compounds which were not removed by
flushing. Heating caused the release of additional materials which had been
absorbed by the plastic. The bags were considered to be decontaminated satis-
factorily when the concentration produced after heating was less than 1 ppm.
The results of this study show that Tedlar bags exposed to high concen-
trations of CH-Clp and CF^ClCFClp can be decontaminated through a procedure
of flushing with N2, heating for 1 hr, then flushing again. Residues of
, however, cannot be removed in this manner.
SEPARATION OF HALOGENATED HYDROCARBONS BY GAS CHROMATOGRAPHY
Volume I of this investigation reported on the separation of halogenated
hydrocarbons by gas chromatography. It discussed the chemical nature of five
columns in common use and listed tables of retention indices. Such tables
are often used as a guide in selecting chromatographic columns for separating
complex mixtures and for making preliminary identifications of components.
12
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In the present study, Kovats retention indices were also measured for
the four compounds of interest. However, in place of the Porapak T column
reported on in Volume I, a column containing a stationary phase consisting of
1,2,3-tris(cyanoethoxy)propane was substituted in the present study. The re-
sults are listed in Table 9. In employing this information in the discussion
below, comparisons have been made with the retention indices tabulated in
Volume I.
The column specified in the Tentative Method (SP-1200) resolves CH2C12
and CF2C1CFC12 well and elutes them before most of the gasoline hydrocarbons,
and from many other halogenated hydrocarbons. The SP-2100 column also resolves
CH3CC13 well but elutes it in the middle of the gasoline spectrum. Therefore,
it would be difficult to resolve this compound on SP-2100 if gasoline vapor
were present. Ethylene dibromide is not resolved on the SP-2100 column. (It
is strongly retained and elutes as a broad peak at high temperatures.)
Carbopak C-HT elutes CH2C123 CF2C1CFC12, and CH3CC13 well before the
gasoline hydrocarbons. This column would appear to be very useful for
determining low molecular weight halogenated hydrocarbons when gasoline
hydrocarbons are present. However, on this column CHC1., and CC1. interfere
with the analysis of CF2C1CFCC12 and CHoCCl-, respectively, and CH2BrCH2Br
is not resolved.
The columns designated FFAP and TCP (see Table 9) appear to offer few
advantages over the two columns that were discussed above for determining the
four compounds of interest. Neither resolves CH2BrCH2Br. Although on TCP,
many halogenated hydrocarbons elute well beyond the gasoline region, CF2C1CFC12
does not.
Retention indices of the four compounds of interest are also included
for the column designated TCEP (see Table 9). It was employed in this
investigation because of its ability to resove CH2BrCH2Br. A column employing
TCEP is used in the Tentative Method for the Determination of Benzene from
Stationary Sources (4), where it has been shown to be a practical column for
field measurements.
13
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REFERENCES
1. Knoll, J. E., M. A. Smith, and M. R. Midgett. Evaluation of Emission
Test Methods for Halogenated Hydrocarbons - Volume I, CCK, C?H/,C1?,
C2C14 and C2HC13- EPA-600/4-79-025, U.S. Environmental Protection
Agendy, Researcn Triangle Park, North Carolina, 1979. 55 pp.
2. Regulators Release Chemicals Hit List. Chem. Eng. News,
56(50):19, 1978.
3. Scheil, G. W. Standardization of Stationary Source Method for Vinyl
Chloride. EPA-600-4-77-026, U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina, 1977. 40 pp.
4. Knoll, J. E., W. H. Penney, and M. R. Midgett. The Use of Tedlar Bags
to Contain Gaseous Benzene Samples at Source Level Concentrations.
EPA-600/4-78-057, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1978. 39 pp.
5. Kovats, E. Gas-Chromatographische Charakterisierung Organischer
Vergindungen Teil 1: Retentionsindices Aliphatischer Halogenide,
Alkohole, Aldehyde und Ketone. Helv. Chem. Acta, 41:1915, 1958.
6. Feinland, R., A. J. Andreatch, and D. P. Cotrupe. Automotive Exhaust
Gas Analysis by Gas-Liquid Chromatography Using Flame lonization
Detection. Anal. Chem., 33(8):991-994, 1961.
7 Data Sub-Committee of. the Gas Chromatography Discussion Group, Gas
Chromatography, 1964, A. Goldup, ed. Institute of Petroleum, London,
1965, p. 303.
8. Wadsworth, G. P. and J. G. Bryan. Introduction to Probability and
Random Variables. McGraw-Hill, New York, 1960, p. 253.
14
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TABLE 1. TIME VARIATION OF CONCENTRATIONS OF HALOGENATED HYDROCARBONS IN
ALUMINUM CYLINDERS
Elapsed Time, days
Slope,
0
i
12
13
20
26
35
43
50
62
68
77
119
120
%/month
Standard Deviation, %/month
Degrees
vv
of Freedom
Concentration, ppm
CF2C1CFC12
14.3
-
13.7
14.0
13.2
14.1
13.1
13.6
13.3
13.6
13.3
12.6
11.8
11.3
-3.67
0.70
11
2.92
CH2C12
-
41.0
40.3
-
38.°
41.6
38.7
39.9
39.1
39.7
38.1
36.4
34.1
32.7
-4.01
0.55
10
4.02
CH3CC13
_
15.0
14.7
-
14.2
15.2
14.1
14.2
14.2
14.4
14.0
13.5
13.1
12.8
-3.07
0.63
10
2.69
*Calculated t-value/Tabulated t-value
15
-------
TABLE 2. VARIATION OF CH-CC1, CONCENTRATION OF GAS MIXTURES STORED IN TEDLAR
BAGS AT AMBIENrTEMPERATURES
ChUCCl., Concentration, ppm
El
k,
'O
apsed Time, days*
0
1
3
4
6
7
8
10
11
12
14
17
days'
-------
TABLE 3. VARIATION OF CH?C19 CONCENTRATION OF GAS MIXTURE STORED IN TEDLAR
BAGS AT AMBIENrTEMPERATURES
El
k,
'0
apsed Time, days*
0
1
4
5
6
7
8
11
12
13
14
days'
>g,days
Bag 1
39.8
-
37.8
38.2
-
37.9
-
35.6
-
35.5
-
-0.01
10.5
CH-Clp Concentration, ppm
Bag 2
183
182
-
176
176
-
173
-
160
-
160
-0.01
10.2
Bag 3
48.4
48.0
-
46.7
47.0
-
46.8
-
43.8
43.6
-0.008
13.9
*From date when bags were prepared.
17
-------
TABLE 4. VARIATION OF CF?C1CFC19 CONCENTRATION OF GAS MIXTURES STORED IN
TEDLAR BAGS AT AMBIENriEMPERATURES
El
k,
^
apsed Time, days*
0
12
13
days"
Ii9,days
Bag 1
11.8
10.2
10.8
-0.009
12
CF2C1CFC12 Concentration,
Bag 2
17.5
15.0
13.3
-0.02
6
ppm
Bag 3
20.0
17.3
18.2
-0.009
11
*From date when bags were prepared.
TABLE 5. VARIATION OF CFLBrOOr CONCENTRATION OF GAS MIXTURES STORED IN
TEDLAR BAGS AT AMBIENT TEMPERATURES
El
k,
t0
apsed Time, days*
0
2
4
5
18
19
days"
^g, days
CH2BrCH2Br Concentration,
Bag 1
20.0
17.3
16.1
14.7
8.1
7.5
-0.05
2.1
ppm
Bag 2
11.4
10.1
8.7
8.1
3.7
3.6
-0.06
1.7
*From date when bags were prepared.
18
-------
TABLE 6. VARIATION OF HALOGENATED HYDROCARBON CONCENTRATIONS OF GAS MIXTURES
STORED IN ALUMINIZED MYLAR BAGS AT AMBIENT TEMPERATURES
Elapsed Time, days*
k, days"
t0>9, days
0
1
2
4
5
Halogenated Hydrocarbon Concentration, jjpjn
CH2C12
20.0
19.5
17.8
-
17.6
-0.026
4.1
CH3CC13
12.0
10.5
-
9.2
9.0
-0.06
1.9
CF2C1CFC12 CH2BrCH2Br
13.3
12.6
-
12.8
12.4
-0.009
11
17.3
13.9
-
12.9
13.1
-0.05
2.2
*From date
TABLE 7.
when bags
EFFECT OF
were prepared,
TEMPERATURE ON
HALOGENATED
HYDROCARBON CONCENTRATION OF
GAS MIXTURES STORED IN ALUMINIZED MYLAR AND TEDLAR
BAGS
Compound
CH3CC13
II
ti
CF2C1CFC12
ii
II
CH?C12
II
Bag
Type
Al -mylar
Tedlar
Tedlar
Al -mylar
Tedlar
Tedlar
Tedlar
Tedlar
Temperature
75
70
70
75
70
70
75
75
Time,
(hr)
16
1
19
16
1
16
1
16
Concentration, ppjn Change
Initial
13.2
197
196
11.7
9.93
18.4
160
165
Final (%)
10.3 -22
196 -0.5
188 -4
11.5 -2
10.1 +2
10.1 -45
165 +3
137 -17
19
-------
TABLE 8. "MEMORY" EFFECTS IN TEDLAR BAGS RESULTING FROM HIGH CONCENTRATIONS
OF HALOGENATED HYDROCARBONS
Concentration, ppm
Compound
CH3CC13
CH2C12
CF2C1CFC12
Initial*
48,300
179,900
142,300
After
flushing
72.6
4.0
0.6
After
heating
105
107
1.1
After
second heating**
4.3
0.9
0.5
After
third heating
4.5
-
-
Calculated from vapor pressure at 0°C.
**Bag flushed before second and third heatings.
TABLE 9. KOVATS RETENTION INDICES OF SELECTED HALOGENATED HYDROCARBONS ON
VARIOUS CHROMATOGRAPHIC COLUMNS
Retention index
Compound SP-2100 FFAP TCP C-HT TCEP
CH2C12
CF2C1CFC12
CH3CC13
CH2C1CHC12
CH2BrCH2Br
CH3CH2Br
516
524
646
753
-
514
934
695
900
1447
-
-
1001
602
980
1172
-
882
362
440
490
565
-
-
1073
639
911
-
1575
-
SP-2100: 20% SP-2100/0.1% Carbowax 1500 on 100/120 mesh Supelcoport
15-ft x 1/8-in stainless steel.
FFAP: Free fatty acid Carbowax 20M reacted with nitroterephathalic acid
(10%) on 80/100 mesh Chromasorb VI AW in 20-ft x 1/8-in stainless steel
TCP: 15% Tetracyanoethylated pentaerythritol on 60/80 mesh Chromasorb P AW
in 16-ft xl/8-in stainless steel.
C-HT: Carbopak C-HT, 80/100 mesh in 6.5-ft x 1/8-in stainless steel.
TCEP: 10% 1,2,3-tris(2-cyanoethoxy)propane on 80/100 mesh Chromasorb P AW
in 6-ft x 1/8-in stainless steel.
20
-------
20.00
IB. 00 •
IE. 00 •
1H.00 •
| 12.00 -
Concentration.
CD CS)
esa csi
rsi ca
B.00 •
H.00 •
2.00 -
0.00 •
E
E
B
B
B
Bag 1 - 20.0 ppm
i
X
X
X Bag 2 - 11 .4 ppm H
B
« X
JEJEJEJESSHHC3NE3
3SHBISISQHE3EIIS
HfMTUllDISNTLDCDIS
----- PJ
Time, days
Figure 1. Decay of ethylene bromide stored in Tedlar bags at ambient temperature
21
-------
APPENDIX A
METHOD FOR THE DETERMINATION OF HAL06ENATED ORGANICS FROM STATIONARY SOURCES
METHOD 23. DETERMINATION OF HALOGENATED
ORGANICS FROM STATIONARY SOURCES
INTRODUCTION
Performance of this method should not be attempted
by persons unfamiliar with the operation of a gas
chromatograph, nor by those who are unfamiliar with
source sampling, as there are many details that are
beyond the scope of this presentation. Care must
be exercised to prevent exposure of sampling personnel
to hazardous emissions.
1. Principle and Applicability
1.1 Principle. An integrated bag sample of stack gas containing
one or more halogenated organics is subjected to gas chromatographlc
(GC) analysis, using a flame ionization detector (FID).
1.2 Applicability. The method 1s applicable to the measurement of
halogenated organics such as carbon tetrachloride, ethylene d1chloride,
perch!oroethylene, trichloroethylene, methylene chloride, 1-1-1 tri-
chloroethane, and trichlorotrlfluoroethane in stack gases only from
specified processes. It is not applicable where the gases are contained
in particulate matter.
2. Range and Sensitivity
The procedure described herein is applicable to the measurement of
halogenated organics in the 0.1 to 200 ppm range. The upper limit may
be extended by further calibration or by dilution of the sample.
3. Interferences
The chromatograph column with the corresponding operating parameters
herein described has been represented as being useful for producing
adequate resolution of halogenated organics. However, resolution
22
-------
interferences may be encountered on some sources. Also, the chrom-
atograph operator may know of a column that will produce a superior
resolution of the particular compound of interest without reducing the
response to that compound, as specified in Section 4.3.1.
In any event, the chromatograph operator shall select a column
which is best suited to his particular analysis problem, subject to the
approval of the Administrator. Such approval shall be considered
automatic provided that confirming data produced through a demonstrably
adequate supplemental analytical technique, such as analysis with a
different column or G.C./mass spectroscopy, is available for review by
the Administrator.
4. Apparatus
4.1 Sampling (see Figure 23-1).
4.1.1 Probe. Stainless steel, Pyrex glass, or Teflon tubing
according to stack temperature, each equipped with a glass wool plug to
remove particulate matter if particulate matter is present.
4.1.2 Sample Line. Teflon, 6.4 mm outside diameter, of sufficient
length to connect probe to bag. A new unused piece is employed for each
series of bag samples that constitutes an emission test.
4.1.3 Male (2) and female (2) stainless steel quick connects,, with
ball checks (one pair without) located as shown in Figure 23-1.
4.1.4 Tedlar or aluminized Mylar bags, 100 liter capacity. To
contain sample.
4.1.5 Rigid leakproof containers for 4.1.4, with covering to
protect contents from sunlight.
Mention of trade names or specific products does not constitute
endorsement by the Environmental Protection Agency.
-------
4.1.6 Needle Valve. To adjust sample flow rate.
4.1.7 Pump—Leak-Free. Minimum capacity 2 liters per minute.
4.1.8 Charcoal Tube. To prevent admission of halogenated organics
to the atmosphere in the vicinity of samplers.
4.1.9 Flow Meter. For observing sample flow rate; capable of
measuring a flow range from 0.10 to 1.00 liters per minute.
4.1.10 Connecting Tubing. Teflon, 6.4 mm outside diameter, to
assemble sample train (Figure 23-1).
4.2 Sample Recovery.
4.2.1 Tubing. Teflon, 6.4 mm outside diameter, to connect bag to
gas chromatograph sample loop. A new unused piece is employed for each
series of bag samples that constitutes an emission test, and is to be
discarded upon conclusion of analysis of those bags.
4.3 Analysis.
4.3.1 Gas Chromatograph. With FID, potentiometric strip chart
recorder and 1.0 to 2.0 ml sampling loop in automatic sample valve. The
chromatographic system shall be capable of producing a response to 0.1
ppm of the halogenated organic compound that is at least as great as the
average noise level. (Response is measured from the average value of
the baseline to the maximum of the waveform, while standard operating
conditions are in use.)
4.3.2 Chromatographic Column. Stainless steel, 3.05 m x 3.2 mm,
containing 20 percent SP-2100/0.1 percent Carbowax 1500 on 100/120
Supelcoport. Other columns can be used, provided that the precision
and accuracy of the analysis of standards are not impaired. Information
confirming that adequate resolution of the halogenated organic compound
24
-------
peak is accomplished should be available. Adequate resolution is
defined as an area overlap of not more than 10 percent of the halo-
genated organic compound peak by an interferent peak. Calculation
of area overlap is explained in Appendix E, Supplement A: "Determi-
nation of Adequate Chromotographic Peak Resolution."
4.3.3 Flow Meters (2). Rotameter type, 0 to 100 ml/min
capacity.
4.3.4 Gas Regulators. For required gas cylinders.
4.3.5 Thermometer. Accurate to one degree centigrade, to measure
temperature of heated sample loop at time of sample injection.
4.3.6 Barometer. Accurate to 5 mm Hg, to measure atmospheric
pressure around gas chromatograph during sample analysis.
4.3.7 Pump--Leak-free. Minimum capacity 100 ml/min.
4.3.8 Recorder. Strip chart type, optionally equipped with disc
integrator or electronic integrator.
4.3.9 Planimeter. Optional, in place of disc or electronic
integrator, for 4.3.8 to measure chromatograph peak areas.
4.4 Calibration. 4.4.2 through 4.4.6 are for section 7.1 which
is optional.
4.4.1 Tubing. Teflon, 6.4 mm outside diameter, separate pieces
marked for each calibration concentration.
4.4.2 Tedlar or Aluminized Mylar Bags. 50-liter capacity, with
valve; separate bag marked for each calibration concentration.
4.4.3 Syringe. 25 yl, gas tight, individually calibrated., to
dispense liquid halogenated organic solvent.
25
-------
4.4.4 Syringe. 50 pi, gas tight, individually calibrated, to
dispense liquid halogenated organic solvent.
i
4.4.5 Dry Gas Meter, With Temperature and Pressure Gauges.
Accurate to +2 percent, to meter nitrogen in preparation of standard gas
mixtures, calibrated at the flowrate used to prepare standards.
4:4.6 Midget Impinger/Hot Plate Assembly. To vaporize solvent.
5. Reagents
It is necessary that all reagents be of chromatographic grade.
5.1 Analysis.
5.1.1 Helium Gas or Nitrogen Gas. Zero grade, for chromatographic
carrier gas.
5.1.2 Hydrogen Gas. Zero grade.
5.1.3 Oxygen Gas or Air as Required by the Detector. Zero grade.
5.2 Calibration. Use one of the following options: either 5.2.1
and 5.2.2, or 5.2.3.
5.2.1 Halogenated organic compound, 99 mo! percent pure, certified
by the manufacturer to contain a minimum of 99 mol percent of the
particular halogenated organic compound; for use in the preparation of
standard gas mixtures as described in Section 7.1.
5.2.2 Nitrogen Gas. Zero grade, for preparation of standard gas
mixtures as described in Section 7.1.
5.2.3 Cylinder Standards (3). Gas mixture standards (200, 100,
and 50 ppm of the halogenated organic compound of interest, in nitrogen)
for which the gas composition has been certified with an accuracy of +3
percent or better by the manufacturer. The manufacturer must have
recommended a maximum shelf life for each cylinder so that the concentration
26
-------
does not change by greater than +_ 5 percent from the certified value.
The date of gas cylinder preparation, certified concentration of the
halogenated organic compound and recommended maximum shelf life must
have been affixed to the cylinder before shipment from the gas manu-
facturer to the buyer. These gas mixture standards may be directly used
to prepare a chromatograph calibration curve as described in Section 7.2.2.
5.2.3.1 Cylinder Standards Certification. The concentration of
the halogenated organic compound in nitrogen in each cylinder must have
been certified by the manufacturer by a direct analysis of each cylinder
using an analytical procedure that the manufacturer had calibrated on
the day of cylinder analysis. The calibration of the analytical pro-
cedure shall, as a minimum, have utilized a three-point calibration
curve. It is recommended that the manufacturer maintain two calibration
standards and use these standards in the following way: (1) a high
concentration standard (between 200 and 400 ppm) for preparation of a
calibration curve by an appropriate dilution technique; (2) a low con-
centration standard (between 50 and 100 ppm) for verification of the
dilution technique used. If the difference between the apparent
concentration read from the calibration curve and the true concentration
assigned to the low concentration standard exceeds 5 percent of the true
concentration, determine the source of error and correct its then repeat
the three-point calibration.
5.2.3.2 Establishment and Verification of Calibration Standards.
The concentration of each calibration standard must have been established
by the manufacturer using reliable procedures. Additionally, each
calibration standard must have been verified by the manufacturer by
27
-------
one of the following procedures, and the agreement between the Initially
determined concentration value and the verification concentration value
must be within +5 percent: (1) verification value determined by
comparison with a gas mixture prepared in accordance with the procedure
described in Section 7.1.1 and using 99 mol percent of the halogenated
organic compounds, or (2) verification value obtained by having the
calibration standard analyzed by the National Bureau of Standards, if
such analysis is available. All calibration standards must be reverified
on a time interval consistent with the shelf life of the cylinder
standards sold.
5.2.4 Audit Cylinder Standards (2). Gas mixture standards identi-
cal in preparation to those in Section 5.2.3 (the halogenated organic
compounds of interest, in nitrogen), except the concentrations are only
known to the person supervising the analysis of samples. The concentrations
of the audit cylinders should be: one low concentration cylinder in the
range of 25 to 50 ppm, and one high concentration cylinder in the range
of 200 to 300 ppm. When available* audit cylinders may be obtained by
contacting: EPA$ Environmental Monitoring and Support Laboratory,
Quality Assurance Branch (MD-77), Research Triangle Park, North Carolina
27711. If audit cylinders are not available at EPA, an alternate source
must be secured.
6. Procedure
6.1 Sampling. Assemble the sample train as in Figure 23-1.
Perform a bag leak check according to Section 7.3.2. Join the quick
connects as illustrated, and determine that all connections between the
bag and the probe are tight. Place the end of the probe at the
28
-------
centroid of the stack and start the pump with the needle valve adjusted
to yield a flow of 0.5 1pm. After a period of time sufficient to purge
the line several times has elapsed, connect the vacuum line to the bag
and evacuate the bag until the rotameter indicates no flow. At all
times, direct the gas exiting the rotameter away from sampling personnel.
Then reposition the sample and vacuum lines and begin the actual sampling,
keeping the rate constant. At the end of the sample period, shut off
the pump, disconnect the sample line from the bag, and disconnect the
vacuum line from the bag container. Protect the bag container from
sunlight.
6.2 Sample Storage. Sample bags must be kept out of direct sun-
light and must be protected from heat. Analysis must be performed
within 1 day of sample collection for methylene chloride, ethylene
dichloride and trichlorotrifluoroethane. Analysis of perchloroethylene,
trichloroehtylene, 1,1, 1-trichloroethane and carbon tetrachloride must
be performed within 2 days.
6.3 Sample Recovery. With a new piece of Teflon tubing identified
for that bag, connect a bag inlet valve to the gas chromatograph sample
valve. Switch the valve to receive gas from the bag through the sample
loop. Arrange the equipment so the sample gas passes from the sample
valve to a 0-100 ml/min rotameter with flow control valve followed by a
charcoal tube and a 0-1 inch w.g. pressure gauge. Sample flow may be
maintained either by a vacuum pump or container pressurization if the
collection bag remains in the rigid container. After sample loop
purging is ceased, allow the pressure gauge to return to zero before
activating the gas sampling valve.
29
-------
TRAIN FOR PREPARATION OF SAMPLES
p
*"••"•»
:\
\
DRY GAS METER
NITROGEN CYLINDER
MIDGET
HOT PLATE
TEDLAR BAG
CAPACITY
50 liters
30
-------
INTEGRATED - BAG SAMPLING TRAIN
F4LTER (GLASS WOOL)
WE—[r
TEFLON
SAMPLE LINE
VACUUM LINE
FLOW METER
QUICK
CONNECTS
(MALE)
TEDLAROR
ALUMINIZED
MYLAR BAG
RIGID LEAK-PROOF
CONTAINER
CHARCOAL TUBE
PUMP
31
-------
6.4 Analysis. Set the column temperature to 100° C, and the
detector temperature to 225° C. When optimum hydrogen and oxygen flow
rates have been determined, verify and maintain these flow rates during
all chromatograph operations. Using zero helium or nitrogen as the
carrier gas, establish a flow rate in the range consistent with the
manufacturer's requirements for satisfactory detector operation. A
flow rate of approximately 20 ml/min should produce adequate separations
Observe the base line periodically and determine that the noise level
has stabilized and that base line drift has ceased. Purge the sample
loop for thirty seconds at the rate of 100 ml/min, then activate the
sample valve. Record the injection time (the position of the pen on
the chart at the time of sample injection), the sample number, the
sample loop temperature, the column temperature, carrier gas flow
rate, chart speed and the attenuator setting. Record the laboratory
pressure. From the chart, note the peak having the retention time
corresponding to the halogenated organic compound as determined in
Section 7.2.1. Measure the halogenated organic compound peak area,
Am, by use of a disc integrator, electronic integrator, or a plani-
meter. Record Am and the retention time. Repeat the injection at
least two times or until two consecutive values for the total area of
the peak do not vary more than 5 percent. The average value for these
two total areas will be used to compute the bag concentration.
6.5 Measure the ambient temperature and barometric pressure near
the bag. From a water saturation vapor pressure table, determine and
record the water vapor content of the bag as a decimal figure. (Assume
the relative humidity to be 100 percent unless a lesser value is known.)
32
-------
7- Standards, Calibration, and Quality Assurance
7.1 Standards.
7.1.1 Preparation of Standard Gas Mixtures. (Optional-delete 1f
cylinder standards are used.) Assemble the apparatus shown 1n Figure
232. Check that all fittings are tight. Evacuate a 50-liter Tedlar or
aluminlzed Mylar bag that has passed a leak check (described in Section
7.3.2) and meter in about 50 liters of nitrogen. Measure the barometric
pressure, the relative pressure at the dry gas meter, and the temperature
at the dry gas meter. Refer to Table 23-1. While the bag is filling,
use the 50 yl syringe to inject through the septum on top of the impinger,
the quantity required to yield a concentration of 200 ppm. In a like
manner, use the 25 pi syringe to prepare bags having approximately 100
and 50 ppm concentrations. To calculate the specific concentrations,
refer to Section 8.1. Tedlar bag gas mixture standards of methylene
chloride, ethylene dichloride, and trichlorotrifluoroethane may be used
for 1 day; trichloroethylene and 1, 1,1-trichloroethene for 2 days;
perchloroethylene and carbon tetrachloride for 10 days from the date of
preparation. (Caution: Contamination may be a problem when a bag is
reused if the new gas mixture standard is a lower concentration than the
previous gas mixture standard.)
7.2 Calibration.
7.2.1 Determination of Halogenated Organic Compound Retention
Time. This section can be performed simultaneously with Section 7.2.2.
Establish chromatograph conditions identical with those in Section 6.3,
above. Determine proper attenuator position. Flush the sampling loop
with zero helium or nitrogen and activate the sample valve. Record the
33
-------
TABLE 23-1. INJECTION VALUES FOR PREPARATION OF STANDARDS. (Optional, see Section 7.1.1)
Liquid Required in 50 1
Compound
Perchloroethylene C^CK
Trichloroethylene C2HC13
1 ,1 ,1-Trichloroethane C2HoCl3
Methylene Chloride CH2C12
Trichlorotrifluoroethane C,,C13F3
Carbon Tetrachloride CC1.
Ethylene Dichloride C9H.C19
Molecular
Weight
(M)
165.85
131.40
133.42
84.94
187.38
153.84
98.96
Density at
293° A
(D)
1.6230
1.4649
1.4384
1.3255
1.5790
1 . 5940
1.2569
for Approximate Concer
200 ppm 100 ppm
42.5
37.3
38.6
26.6
49.3
40.1
32.7
21.2
18.6
19.3
13.3
24.7
20.1
16.4
itration of:
50 ppm
10.6
9.3
9.6
6.7
12.3
10.0
8.2
-------
Injection time, the sample loop temperature, the column temperature, the
carrier gas flow rate, the chart speed and the attenuator setting.
Record peaks and detector responses that occur 1n the absence of the
halogenated organic. Maintain conditions (with the equipment plumbing
arranged identically to Section 6.3), flush the sample loop for 30
seconds at the rate of 100 ml/m1n with one of the halogenated organic .
compound calibration mixtures, and activate the sample valve. Record
the injection time. Select the peak that corresponds to the halogenated
organic compound. Measure the distance on the chart from the Injection
time to the time at which the peak maximum occurs. This distance divided
by the chart speed is defined as the halogenated organic compound peak
retention time. Since it is possible that there will be other organics
present in the sample, it is very important that positive identification
of the halogenated organic compound peak be made.
7.2.2 Preparation of Chromatograph Calibration Curve. Make a gas
chromatographic measurement of each standard gas mixture (described in
Section 5.2.3 or 7.1.1) using conditions identical with those listed in
Sections 6.3 and 6.4. Flush the sampling loop for 30 seconds at the
rate of 100 ml/min with one of the standard gas mixtures and activate
the sample valve. Record Cr, the concentration of halogenated organic
C
injected, the attenuator setting, chart speed, peak area, sample loop
temperature, column temperature, carrier gas flow rate, and retention
time. Record the laboratory pressure. Calculate A , the peak area
c
multiplied by the attenuator setting. Repeat until two consecutive
injection areas are within 5 percent, then plot the average of those two
35
-------
values versus C . When ther other standard gas mixtures have been
\+
similarly analyzed and plotted, draw a straight line through the points.
Perform calibration daily, or before and after each set of bag samples,
whichever is more frequent.
7.3 Quality Assurance.
7.3.1 Analysis Audit. Immediately after the preparation of the
calibration curve and prior to the sample analyses, perform the analysis
audit described in Appendix E, Supplement B: "Procedure for Field
Auditing GC Analysis."
7.3.2 Bag Leak Checks. While performance of this section is
required subsequent to bag use, it is also advised that it be performed
prior to bag use. After each use, make sure a bag did not develop leaks
as follows: to leak check, connect a water manometer and pressurize the
bag to 5-10 cm H,>0 (2-4 in. H20). Allow to stand for 10 minutes. Any
displacement in the water manometer indicates a leak. Also, check the
rigid container for leaks in this manner. (Note: an alternative leak
check method is to pressurize the bag to 5-10 cm H20 or 2-4 in. H20 and
allow to stand overnight. A deflated bag indicates a leak.) For each
sample bag in its rigid container, place a rotameter in line between the
bag and the pump inlet. Evacuate the bag. Failure of the rotameter to
register zero flow when the bag appears to be empty indicates a leak.
8. Calculations
8.1 Optional Standards Concentrations. Calculate each halogenated
organic standard concentration prepared in accordance with Section 7.1.1
as follows:
36
-------
D yg 1Q3 pg yig mole 24.055 yl lf>6
cc
ul mg M yg yg mole
„ v 106 yl 293
m 1 Tm
Jyp (24.055 x 103)
Vl v 293 Pm
Fm
760
Ei
Equation 23-1
'm T "T^ 760
Where:
C = Standard concentration in ppm.
B = Number of yl of injected.
Vm = Gas volume measured by dry gas meter in liters.
Y = Dry gas meter calibration factor.
P = Absolute pressure of the dry gas meter, mm Hg.
Tm = Absolute temperature of the dry gas meter, °A.
D = Density of compound at 293° A.
M = Molecular weight of compound.
24.055= Ideal gas at 293° A, 760 mm Hg.
10 = Conversion factor, ppm.
8.2 Sample Concentrations. From the calibration curve described in
Section 7.2.2 above, select the value of C that corresponds to A Calcu-
C N*
late C as follows:
c.
s
Where:
S , = The water vapor content of the bag sample, as analyzed.
wb
C = The concentration of the halogenated organic in the sample
in ppm.
37
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Ti
Pi
= The concentration of the halogenated organic indicated by
the gas chromatograph, in ppm.
= The reference pressure, the laboratory pressure recorded
during calibration, mm Hg.
= The sample loop temperature on the absolute scale at the
time of analysis, °A.
= The laboratory pressure at time of analysis, mm Hg.
T = The reference temperature, the sample loop temperature
recorded during calibration, °A.
9. References
1. Feairheller, W. R.; Kenrner, A.M.; Warner, B. J.; and
Douglas, D. Q. "Measurement of Gaseous Organic Compound Emissions by Gas
Chromatography," EPA Contract No. 68-02-1404, Task 33 and 68-02-2818, Work
Assignment 3. January 1978. Revised August, 1978, by EPA.
2. Bullein 747. "Separation of Hydrocarbons" 1974. Supelco, Inc.
Bellefonte, Pennsylvania 16823.
3. Communication From Joseph E. Knoll. Perch!oroethylene Analysis
by Gas Chromatography. March 8, 1978.
4. Communication From Joseph E. Knoll. Test Method for Halogenated
Hydrocarbons. December 20, 1978.
38
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TECHNICAL REPORT DATA
(Please read Immicnoi'.s on the reverse before comnletiiifl
C EPA "600/4-80-003
3. RECIPIENT'S ACCESSION-NO.
4. T:TL= A\O SUBTITLE
EVALUATION OF EMISSION TEST METHODS FOR HALOGENATED
HYDROCARBONS - VOLUME II: CH9C10, CH,CC1,, CF9C1CFC10,
AND Ch
5. REPORT DATE
January 1980
6. PERFORMING ORGANIZATION CODE
7. ALTHORiS!
Joseph E. Knoll, Mark A. Smith and M. Rodney Midgett
8. PERFORMING ORGANIZATION REPORT NO.
3. PERFORMING ORGANIZATION NAME AND ADDRESS
Duality Assurance Division
Environmental Monitoring Systems Laboratory
J.S. Environmental Protection Agency
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
A09A1D
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Monitoring Systems Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park. NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA 600/08
15. SUPPLEMENTARY NOTES
To be published as an Environmental Monitoring Series Report
16. ABSTRACT
A test method for halogenated hydrocarbons has been evaluated and information is
provided for the user. Four compounds were investigated, methylene chloride," methyl
chloroform, Freon 113 and ethylene dibromide. Cylinder gases used for calibration and
auditing were tested for stability. Decreases in concentration of 3-4% per month were
observed. Tedlar and aluminized Mylar containers were also tested. Tedlar bags were
found to be superior, maintaining Freon 113 samples stable for 10 days, methyl chloro-
form for 7 days, methylene chloride for 6 days and ethylene dibromide for 2 days, at
room temperature. Heating caused decreases in stabilities. Heated ethylene dibromide
samples were more stable in aluminized Mylar than in Tedlar. A procedure was developed
to remove persistent residues from TerJlar bags that had contacted high concentrations
of halogenated hydrocarbons. Information is also included on gas chromatographic
columns for use in tMs method of analysis.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
air pollution
gas sampling
halogenated hydrocarbons
Tedlar bags
aluminized Mylar bags
43F
68A
3. C/tjTRliiUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS ( This keporti
UNCLASSIFIED
21. NO. OF PAGES
39
20. SECURITY CLASS (This page I
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
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