United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Las Vegas NV89114
Research and Development
EPA-600/S4-84-081 Dec. 1984
&EPA Project Summary
Interim Protocol for the
Automated Analysis of
Semivolatile Organic
Compounds by Gas
Chromatography/Fourier
Transform Infrared (GC/FT-IR)
Spectrometry
Donald F. Gurka
A GC/FT-IR protocol is described
which is applicable to the determination
of semivolatile organic compounds in
wastewater, soils, sediments and solid
wastes. The protocol is designed for the
high-throughput automated analysis of
multicomponent environmental and
hazardous waste extracts. Wastewater
analysis for semivolatile organic com-
pounds is based upon extracting 1 L of
sample with methylene chloride and
concentrating the extract to 1 mL. The
analysis of the semivolatile fraction
derived from solid waste is based upon
extracting 50 grams of sample and
concentrating the sample extract to 1.0
mL. A gel permeation option is included
to further purify those extracts that
cannot be concentrated to the specified
final volume. Using capillary GC/FT-IR
techniques, wastewater identification
limits of 150 to 400 ppb can be
achieved with this method while the
corresponding identification limits for
solid samples are 3 to 8 ppm. Automated
packed column GC/FT-IR identification
limits are approximately a factor of five
higher than the corresponding capillary
GC/FT-IR values. The most frequent
obstacle to achieving these identification
limits is expected to be the presence of
large quantities of interfering high
boiling co-extractants. These co-extract-
ants would raise the identification limits
by preventing the concentration of
extracts to the desired final volume,
thereby necessitating gel permeation
cleanup, and/or by decreasing the
spectral signal-to-noise of GC-volatile
analytes by raising the spectral back-
ground intensity.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Las Vegas, NV, 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 applicability of the gas chromatog-
raphy/Fourier transform infrared (GC/FT-
IR) spectrometric technique to the
analysis of wastewater, soils, sediments,
hazardous wastes, and diesel particulates
has been demonstrated. Although this
technique is currently one to two orders
of magnitude less sensitive than gas
chromatography/mass spectrometry
(GC/MS), with sufficient extract concen-
tration, GC/FT-IR is capabls of detecting
about 75 percent of the GC/MS detectable
analytes. The scope of current GC/MS
confirmatory techhiques is currently
limited by the availability of suitable GC
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retention time standards; however,
suitable spectral confirmatory techniques,
such as GC/FT-IR, could eliminate this
problem. However, general acceptance of
the GC/FT-IR technique as a routine
monitoring tool has been hindered by the
lack of validated analytical protocols
which provide data of known precision
and accuracy.
Conclusions and
Recommendations
The analytical protocol described is
adequate for the identification of environ-
mental contaminants at the mid ppb to
low ppm range. The principal problem in
applying this protocol to environmental
samples is expected to be the concentra-
tion of solid waste extracts to 1 mL In
these cases, the extract may be cleaned
up by gel permeation or the analyst may
settle for higher identification limits.
Computer software is required to
determine real-time relative IR peak
intensities. This software is required to
provide relative intensity, as well as
frequency precision, acceptance criteria
for analyte identification. In addition, a
consensus is required from the spectro-
scopic community on suitable chemical
candidates for vapor-phase frequency
calibration of the GC/FT-IR system (one
reviewer has suggested indene for this
role). This consensus should be sought
from the Coblentz Society and/or the
appropriate American Society for Testing
Materials (ASTM) committee.
Finally, the minimum identifiable
quantities of typical environmental
contaminants should be determined in a
round-robin study. This study should
employ laboratories equipped with differ-
ent model GC/FT-IR systems. This study
is necessary because there are currently
11 commercial suppliers of FT-IR spectro-
meters. The round-robin study should be
coordinated through the appropriate
ASTM and/or Coblentz Society Commit-
tees.
Results and Discussion
The minimum identifiable quantity
(MIQ) of 54 environmentally important
compounds using on-line GC/FT-IR
techniques have been determined. The
capillary GC/FT-IR MIQ's range from 300
ng of molecules with oxygen containing
functional groups to 800 nanograms (ng)
of thepolynucleararomaticsfluoreneand
phenanthrene. This corresponds to a
sample sensitivity of 150 to 400 parts per
billion (ppb)for wastewater, if 1 Lof water
is extracted and the extract concentrated
to 1 mLwith2A
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cm 1 or less. Thus, to report an analyte as
"identified," the frequencies of the major
IR bands in the analyte and library spectra
should agree to at least ±crrf1 and the
nominal spectral frequencies for the ana-
lyte and library spectra should be deter-
mined with the same computer software.
Acceptance criteria for the relative in-
tensities of the major IR bands in the ana-
lyte and library spectra should also be es-
tablished, but at present, the necessary
computer software is not available.
The wastewater and solid sample
workup methods used in this protocol
have been described in detail elsewhere.
The wastewater workup is based on
Method 625 and has been modified to
include the fused silica capillary (FSCC)
extract analysis method of Sauter and
Betowski. The solid sample workup
technique has been developed by the
Battelle, Midwest and Southern Institutes.
This procedure has been validated for the
largest solid sample size of any currently
available method. A gel permeation op-
tion has been included for those extracts
which cannot be sufficiently concen-
trated to attain the desired detection limit.
In addition to the earlier described
frequency precisions, many other quality
assurance/quality control (QA/QC)
procedures are incorporated within the
protocol. These include criteria for the
instrumental centerburst intensity as a
function of temperature and spectrometer
day-to-day stability. QA/QC procedures
are roughly divided into the classes of
Daily, Periodic, and Initial Setup checks.
Daily QA/QC includes a 100 percent Line
Test, Single Beam Test, Spectrometer
and Mirror Align Tests, and Lightpipe and
Beam Splitter protective procedures.
Periodic QA/QC procedures include a
detector check, frequency calibration,
and capillary and packed column sensitiv-
ity tests. Initial setup QA/QC includes in-
terferometer and detector checks, fre-
quency calibration, an interface sensitiv-
ity check, the determination of minimum
identifiable quantities of target compounds,
and the preparation of a calibration plot of
detector centerburst intensity versus
lightpipe temperature.
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The EPA author Donald F. Gurka is with the Environmental Monitoring Systems
Laboratory, Las Vegas, NV 89114.
The complete report, entitled "Interim Protocol for the Automated Analysis of
Semivolatile Organic Compounds by Gas Chromatography/Fourier Transform
Infrared(GC/FT-IR) Spectrometry," (Order No. PB 85-115 186; Cost: $8.50,
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
Donald F. Gurka can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
P.O. Box 15027
Las Vegas, NV 89114
U.S. GOVERNMENT PRINTING OFFICE; 559-016/7869
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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