United States Atmospheric Research and

Environmental Protection Exposure Assessment Laboratory

Agency Research Triangle Park, NC 27711

E AP Project Summary

Field Test of a Generic Method

For Halogenated Hydrocarbons:

A VOST Test at a Chemical

Manufacturing Facility

Research and Development EPA/600/SR-94/113 January 1995

Laboratory evaluation studies were

performed for the volatile halogenated

organic compounds (VHOCs) listed in

Title III of the Clean Air Act Amendments (CAAA) of 1990 to determine

chromatographic retention times, recoveries from sorbent, and method detection limits, as well as to design (where

necessary), construct, and evaluate dynamic spiking equipment and procedures for VOST. An initial field evaluation study was conducted for the VOST

(SW-846 sampling Method 0030, analytical Method 5041) with dynamic spiking of VHOCs. A chemical manufacturing facility was selected as a second

test site. The presence of low levels of

some of the compounds of interest was

established by the VOST analysis of

samples collected during a presurvey.

For the field evaluation study, quadruple trains were operated from 4 collocated sampling probes, with 2 dynamically-spiked trains and 2 unspiked

trains. A sampling scheme to meet the

requirements of method evaluation was

designed statistically (following the

guidelines for EPA Method 301), and

the data were evaluated statistically. Of

23 VHOCs tested, the VOST showed

acceptable performance with respect

to recovery and precision for 17.

This Project Summary was developed

by EPA’s Atmospheric Research and

Exposure Assessment Laboratory, Research Triangle Park, NC, to announce

key findings of the research project

that is fully documented in a separate

report of the same title (see Project

Report ordering information at back).

Introduction

The validation of a method for a particular analyte or group of analytes means

that the performance of the methodology

for these analytes has been established

and demonstrated through field tests at

the type of source category of interest,

and that the precision and bias of the

method have been established experimentally. The U. S. EPA, under the authority

of Title III of the CAAA of 1990, required

the identification and/or validation of sampling and analytical methods for the

VHOCs listed in Table 1. The candidate

method is VOST, which consists of SW846 Sampling Method 0030 and SW-846

Analytical Method 5040 or 5041. EPA determined that the VOST method should

first be evaluated in a laboratory environment to establish the veracity of the spiking procedure and the potential applicability of the analytical procedures for the

compounds listed in Table 1.

The VOST was evaluated at a coalfired power plant using quadruple VOST

trains sampling from 4 collocated sampling probes to provide further verification

of the dynamic spiking methodology in a

non-laboratory environment and to assess

the added effect of sampling a combustion matrix upon the performance of the

methodology. Data obtained in the first

field evaluation showed that the VOST did

not perform acceptably for all of the candidate analytes. The methodology was not

expected to show acceptable performance

for all of the candidate analytes listed in

Table 1, but all of the candidate analytes

were included in the testing to demonstrate definitively when the methodology

J.F. McGaughey, J.T. Bursey, and R.G. Merrill
2

would not perform well and to provide

quantitative data to assess method performance. Three of the candidate analytes could not be analyzed by the VOST

analytical methodology: epichlorohydrin,

bis(chloromethyl) ether, and chloromethyl

methyl ether. These 3 compounds are polar, water-soluble, and very reactive, so

they either could not be purged from the

water or reacted with the water.

A second field evaluation study was

conducted at a chemical manufacturing

facility where chemical waste was incinerated. Dynamic spiking of the analytes listed

in Table1 was performed, using 4 collocated sampling probes with 4 similar VOST

trains. The guidelines of EPA Method 301

were used to design the sampling strategy to ensure that adequate samples were

available for statistical evaluation of bias

and precision.

Procedure

The objective of this program was to

perform a second field evaluation of the

VOST method (sampling method SW-846

Method 0030; analytical method, SW-846

Method 5041) at a chemical manufacturing facility that incinerated chemical waste,

to allow the collection of sufficient data to

be able to establish the bias and precision

of the method for the VHOCs listed in

Title III of the CAAA of 1990.

To achieve this objective, a field test

site was selected to allow access for the

quadruple sampling trains required for testing, with 4 collocated sampling probes.

Collection and evaluation of the data followed one of the acceptable approaches

detailed in EPA Method 301: dynamic analyte spiking. The criteria for acceptable

performance of the method for an analyte

are recovery within the range of 50% to

150% with precision (expressed as percent relative standard deviation of replicate determinations) of 50 or less.

Sampling was performed by withdrawing gas from a single port in the stack

through a Quad probe, then directing the

sampled gas simultaneously to 4 similar

VOST sampling trains. The Quad probe

consists of 4 heated probes that can be

inserted into the stack as one unit. The

front end of the Quad probe was positioned in the center of the stack and remained in that location during each day of

testing. No traverse of the stack was performed with the Quad probe. The true

concentrations of the components of the

stack gas were of no interest to this program as long as any quantities of the

compounds of interest were equal for each

train. For VOST sampling during the field

evaluation, two of the trains of each Quad

run were dynamically spiked and two were

unspiked. Sampling procedures followed

Method 0030.

Dynamic spiking of candidate VOST

compounds was performed using a compressed gas cylinder containing the

VHOCs. The boiling point maximum of

100°C cited in Method 0030 was extended

to approximately 135°C to include chlorobenzene and ethylene dibromide, compounds frequently determined by the

VOST methodology. The apparatus shown

in Figure 1 was used for dynamic spiking

in the field, with the spiking gas allowed to

flow through the spiking apparatus for 2

hr before directing the flow to the sampling trains to minimize any adsorptive

Table 1. Halogenated Compounds for Which Laboratory Testing has Determined the Applicability of the VOST Method

Compound Boiling point (°C) Comments

allyl chloride 44-46 Acceptable performance in laboratory

bis(chloromethyl) ether 1061 Decomposes in water; cannot be analyzed

carbon tetrachloride 77 Recovery too high in laboratory study

chlorobenzene 1321 Acceptable performance in laboratory

chloroform 60.6-61.5 Acceptable performance in laboratory

chloromethyl methyl ether 55-57 Decomposes in water; cannot be analyzed

chloroprene 59.4 Acceptable performance in laboratory

1,3-dichloropropylene 105-1062 Acceptable performance in laboratory

epichlorohydrin 115-1771 Decomposes in water; cannot be analyzed

ethyl chloride (chloroethane) 123 Acceptable performance in laboratory

ethylene dichloride (1,2-dibromoethane) 131-1321 Acceptable performance in laboratory

ethylidene dichloride (1,2-dichloroethane) 83 Acceptable performance in laboratory

methyl bromide (bromomethane) 43 Recovery unacceptably high in laboratory

methyl chloride (chloromethane) -24.23 Erratic and unacceptable in laboratory

methyl chloroform (1,1,1-trichloroethane) 74-76 Recovery too high in laboratory study

methylene chloride 39.8-40 Recovery too high in laboratory study

methyl iodide (iodomethane) 41-43 Acceptable performance in laboratory

propylene dichloride (1,2-dichloropropane) 95-96 Acceptable performance in laboratory

tetrachloroethylene 1211 Acceptable performance in laboratory

1,1,2-trichloroethane 110-1151 Acceptable performance in laboratory

trichloroethylene 86.9 Acceptable performance in laboratory

vinyl chloride -13.43 Acceptable performance in laboratory

vinyl bromide 164 Acceptable performance in laboratory

vinylidene chloride (1,1-dichloroethylene) 30-32 Acceptable performance in laboratory

1 Above the maximum VOST boiling point of 100°C; included in the testing because compounds in the range of 100-132°C are frequently tested by the VOST method. 2 Boiling temperature at 730 mm Hg. 3 Below the common lower temperature limit of 30°C usually used for VOST. 4 Boiling temperature at 750 mm Hg.
3

losses in the sampling trains. The concentration of compounds in the cylinder

was verified by laboratory GC/MS and GC/

multiple detector analysis of a diluted

sample prepared in a SUMMA®*-polished

canister.

Analysis of field samples was performed

according to SW-846 Method 5041, analyzing each tube individually to establish

distribution of compounds. A total of 6

complete and valid Quad runs (24 Tenax®/

Tenax®-charcoal pairs, 12 spiked, 12

unspiked) is required to satisfy the requirements of the field validation protocol.

However, a total of 10 Quad runs was

performed to provide back-up samples in

the event that any samples became invalid due to breakage or loss during analysis. The 2 tubes associated with each

sample pair were analyzed separately, always analyzing the Tenax®-charcoal tube

first to minimize the possibility of carryover

from the front tube, where higher compound concentrations were expected. All

VOST sampling tubes were transported

Regulator

(temperature controlled)

Certified

standard

(spiking

compounds)

To train A

Chassis (temperature controlled)

To train B

Fine metering valves

(Flow control)

1/4" Teflon line

(Heat traced

and insulated)

Variacs

(To provide temperature control)

Temperature

display

Thermocouple selector

250°F

Figure 1. VOST spiking apparatus.

and stored at 4°C and were analyzed

within 30 days after collection.

Results and Discussion

The complete analytical results for each

sampling train, showing recoveries of dynamically-spiked compounds and of surrogate compounds for the front and back

tubes individually are shown in Appendix

A of the project report. No corrections

were performed for background concentrations because analyte concentrations

in the background samples were less than

five times the Method Detection Limit.

Mean analyte recoveries and precision for

6 sampling runs are summarized in Table

2.

The results for the first and second

VOST field evaluation studies are compared in Table 3. Using the criteria for

acceptable performance of recovery between 50 and 150%, with precision (as

expressed by relative standard deviation)

of 50 or less, acceptable performance of

the VOST methodology for a given compound is indicated in Table 3 by an asterisk.

Methyl chloride exhibited recoveries far

above the acceptable range, consistent

with results obtained in previous studies.

The common factor in the excessive recoveries for methyl chloride appears to be

formation of the compound in the time

that the halogenated organic compounds

are adsorbed on the sorbent tubes. Method

8240 shows acceptable and reproducible

performance for methyl chloride, but sorbent residence times are minimal in this

analytical methodology. Where sorbent

residence time is minimal (e.g., spiked

sorbent tubes are analyzed immediately),

recoveries are within the reasonable range,

although somewhat high. When methyl

chloride and other halogenated compounds are retained on the sorbent for a

period of days, excessive values for methyl chloride recovery are observed. Analytical results for methyl chloride using the

VOST methodology are biased high, frequently by a factor of ten or more.

Analyte distribution is summarized in

Table 4. As expected, methyl chloride,

ethyl chloride, methyl bromide, and vinyl

chloride are found almost exclusively on

the back tube, because these compounds

break through Tenax® very readily. However, methyl bromide and ethyl chloride * Mention of trade names or commercial products does

not constitute endorsement or recommendation for

use.
4

Table 2. Summary of Mean Recovery and Precision for 6 VOST Sampling Runs Using Dynamic Spiking

Recovery 50-150%—Precision ≤ 50% Relative Standard Deviation (RSD)

Compound Average recovery (%) % RSD

propylene dichloride (1,2-dichloropropane) 121 24.8

trichloroethylene 119 26.2

chloroform 91.3 31.1

methyl chloroform (1,1,1-trichloroethane) 91.1 24.6

methylene chloride 89.9 14.3

ethylidene dichloride (1,1-dichloroethane) 82.2 23.3

chlorobenzene 81.2 22.1

carbon tetrachloride 81.2 23.6

1,1,2-trichloroethane 79.7 27.2

ethylene dibromide (1,2-dibromoethane) 79.6 37.4

cis-1,3-dichloropropene 79.5 27.6

vinylidene chloride (1,1-dichloroethylene) 77.8 24.2

chloroprene 72.4 23.0

ethylene dichloride (1,2-dichloroethane) 72.3 37.5

tetrachloroethene 60.1 27.9

methyl bromide (bromomethane) 54.8 26.2

trans-1,3-dichloropropene 52.3 35.4

Acceptable recovery, unacceptable precision

methyl iodide (iodomethane) 79.5 63.1

Unacceptable recovery (low), acceptable precision

vinyl chloride 41.8 44.6

allyl chloride (3-chloropropene) 35.6 33.3

ethyl chloride (chloroethane) 33.7 36.9

vinyl bromide 29.8 29.7

Unacceptable recovery (high), unacceptable precision

methyl chloride (chloromethane) 243 62.8

frequently show an approximately even

distribution between the front tube and

the back tube. Other compounds are distributed between the front tube and back

tube, with the highest compound concentration on the front tube. Highly halogenated compounds such as methylene chloride, carbon tetrachloride, and methyl chloroform show a distribution between front

and back tubes, but with a clear predominance on the front tube. Using the criterion of 30% distribution on the back tube

as an indicator of breakthrough (Handbook: Quality Assurance/Quality Control

(QA/QC) Procedures for Hazardous Waste

Incineration, EPA/625/6-89/023, January,

1990), no breakthrough was observed for

any compound.

Conclusions

The following conclusions can be drawn

from the data obtained in VOST field evaluation:

• The VOST method performed acceptably for the majority of the candidate

VHOCs in 2 field tests. The VOST

methodology showed unacceptable

performance for only 2 compounds in

both field evaluation studies: methyl

chloride and allyl chloride.

• The VOST method performed acceptably for the following compounds in

only 1 field evaluation: vinyl chloride,

ethyl chloride, vinyl bromide, ethylene

dibromide, and chloroprene. The success of the methodology for these

analytes is source-dependent.

• Vinyl chloride, allyl chloride, chloroprene, and vinyl bromide all show

marginal or unsuccessful performance

in the VOST methodology. The presence of the double-bond in the analyte molecule appears to significantly

decrease the probability of successful

performance of the VOST method.

On the basis of laboratory and field

evaluation studies for the VHOCs from

Title III of the CAAA of 1990, the following

recommendations are made:

• Consideration of the chemical properties of the compounds which were not

amenable to the VOST analytical

methodology (epichlorohydrin, chloromethyl methyl ether, bis[chloromethyl]

ether) predicts that successful performance is very unlikely. These compounds are reactive, polar, and water-soluble. A method other than the

VOST will be required for the successful sampling and analysis of these

types of compounds.

• Methyl chloride has demonstrated excessively high values for recoveries

in two field evaluation studies, as well

as in laboratory studies. Because of

this high bias, the VOST is not recommended as a sampling and analytical method for this compound.

• Further study of the VOST should be

performed and/or VOST data should

be collected in order to set appropriate recovery limits for the surrogates

recommended in the analytical

method. At present, the surrogates

can only be used qualitatively: poor

surrogate recoveries indicate problems with the matrix or the methodology.

• Modification or replacement of the

VOST methodology should be investigated to provide a feasible sampling

and analytical method for the volatile,

polar, water-soluble compounds listed

in Title III of the CAAA of 1990.
5

Table 3. Comparison of Results for First and Second VOST Field Evaluations

First field test 1 Second field test 1

Compound Recovery(%) RSD (%) Recovery (%) RSD (%)

methyl chloride 937 53.8 243 62.8

ethylidene dichloride 75.7* 13.7 82.2* 23.3

chlorobenzene 88.2* 22.0 81.2* 22.1

vinyl chloride 110.4* 27.3 41.8 44.6

vinylidene chloride (1,1-dichloroethylene) 88.0* 31.3 77.8* 24.2

chloroform 81.8* 14.8 91.3* 24.6

propylene dichloride (1,2-dichloropropane) 67.2* 9.6 121* 24.8

methyl bromide (bromomethane) 53.7* 20.2 54.8* 26.2

ethyl chloride (chloroethane) 50.3* 28.7 33.7 36.9

methylene chloride 77.7* 27.1 89.9* 14.3

methyl chloroform (1,1,1-trichloroethane) 110* 43.5 91.1* 31.1

carbon tetrachloride 107* 47.2 81.2* 23.6

ethylene dichloride (1,2-dichloroethane) 76.6* 33.0 72.3* 37.5

trichloroethylene 126* 15.6 119* 26.2

cis-1,3-dichloropropene 137* 26.0 79.5* 27.6

trans-1,3-dichloropropene 135* 38.1 52.3* 35.4

1,1,2-trichloroethane 98.0* 22.1 79.7* 27.2

tetrachloroethene 97.7* 21.9 60.1* 27.9

methyl iodide (iodomethane) 72.8* 37.6 79.5 63.1

allyl chloride (3-chloropropene) 29.9 19.5 35.6 33.3

ethylene dibromide (1,2-dibromoethane) 34.9 31.6 79.6* 37.4

chloroprene 40.1 22.4 72.4* 23.0

vinyl bromide 60.7* 34.3 29.8 29.7

Table 4. Distribution Between Front and Back Tubes According to Compound

Compound Average recover (front) Average recovery (back)

Compounds recovered on the front tube (≥ 90% on front tube)

cis-1,3-dichloropropene 100.0 0.0

trans-1,3-dichloropropene 99.9 0.1

ethylene dichloride (1,2-dibromoethane) 99.9 0.1

trichloroethene 99.7 0.3

tetrachloroethene 99.6 0.4

chlorobenzene 99.5 0.5

propylene dichloride (1,2-dichloropropane) 99.5 0.5

chloroprene 99.0 1.0

1,1,2-trichloroethane 97.7 2.3

ethylene dichloride (1,1-dichloroethane) 96.8 3.2

chloroform 95.8 4.2

allyl chloride (3-chloropropene) 93.7 6.3

methyl iodide (iodomethane) 93.2 6.8

ethylene dichloride (1,2-dichloroethane) 92.0 8.0

Compounds distributed between front and back tubes

methyl chloride (chloromethane) 16.5 83.5

vinyl chloride 19.3 80.7

methyl bromide (bromomethane) 36.5 63.5

chloroethane 55.1 44.9

vinyl bromide 73.2 26.8

methylene chloride (chloromethane) 81.7 18.3

carbon tetrachloride 84.5 15.5

methyl chloroform (1,1,1-trichloroethane) 86.3 13.7

Chloromethyl methyl ether, bix(chloromethyl) ether, and epichlorohydrin could not be analyzed by the VOST methodology.

* Acceptable performance by the analyte in the VOST method, using acceptability criteria of 50-150% recovery with percent Relative Standard Deviation (RSD) of 50 or less.

1 Mean of 6 runs (twelve pairs) uncorrected for background.
6

James F. McGaughey, Joan T. Bursey, and Raymond G. Merrill are with Radian

Corporation, Research Triangle Park, NC 27709.

Merrill D. Jackson is the EPA Project Officer (see below).

The complete report, entitled "Field Test of a Generic Method for Halogenated

Hydrocarbons: A VOST Test at a Chemical Manufacturing Facility," (Order No.

PB95-129144/AS; Cost: $19.50, subject to change) will be available only from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at:

Atmospheric Research and Exposure Assessment Laboratory

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

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POSTAGE & FEES PAID

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PERMIT NO. G-35

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Official Business

Penalty for Private Use $300

EPA/600/SR-94/113