United States
Environmental Protection
Agency
Environmental Research
Laboratory
Athens, GA 30613-7799
Research and Development
EPA/600/S4-91/004 April 1991
Project Summary
Multispectral Identification of
Potentially Hazardous
Byproducts of Ozonation and
Chlorination: Part I, Studies of
Chromatographic and
Spectroscopic Properties of MX
Timothy W. Collette, Russell F. Christman, John M. McGuire and Cheryl Trusty
The gas chromatographic (GC) and
Fourier transform infrared and mass
spectroscopic (FT-IR and MS, respec-
tively) properties'of (Z)-2-chioro-3-
(dichloromethyl)-4-oxobutenoic acid
(MX) (a highly mutagenic byproduct of
drinking water Chlorination) and several
related compounds were studied. Spe-
cifically, MX, the methyl ester of MX
(MX-OMe), and three MX-model com-
pounds [mucochloric acid (MCA),
mucobromic acid (MBA), and 2,4-
(3H,5H)-furandione (24FD)] were ana-
lyzed on our GC/FT-IR and GC/MS sys-
tems. A concentration study of MX on
the GC/FT-IR system revealed a mini-
mum identifiable quantity of approxi-
mately 10 ng, with linear response over
the range of 10 to 600 ng. MX was
stable to approximately 260°C. The
thermal decomposition product pro-
duced above that temperature was ten-
tatively identified by GC/MS as 2-
(dichloromethyl)-3-chloro-2-propenal.
The GC/FT-IR detector response for 600
ng of MX was compared to that of 600
ng of MX that had been methylated.
The ratio of the detector responses in-
dicated that the methylation efficiency
was, at best, 40%.
Additionally, several extracts of
chlorinations of dissolved organic ma-
terial (DOM) were analyzed by GC/FT-
IR and GC/MS. No MX was detected in
any of these extracts. The approximate
extraction efficiencies of MX and MCA
were determined for several organic
solvents, of which ethyl acetate was
the most efficient for both compounds.
A direct aqueous injection of the water
fraction from a DOM Chlorination study
was made on the GC/FT-IR system. Only
simple aliphatic acids were detected. A
preliminary alkaline hydrolysis study
was undertaken with MCA at a reaction
pH of 9.6 at 85°C. No MCA was de-
tected after 1 hour.
This Project Summary was developed
by EPA's Environmental Research
Laboratory, Athens, GA, 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).
Research Perspective
The goal of this research is to identify
and determine the frequency of occurrence
of potentially harmful contaminants in
drinking water. The byproducts of disin-
fection (primarily Chlorination and
ozonation) are of principal concern, due
to their ubiquity. The focus of the current
work was to evaluate analytical methods
for the identification of MX, by GC/FT-IR
and GC/MS. Identification schemes for MX
have previously involved either methyla-
tion or PFBOA derivatization. Although hot
complete, our studies indicate that, if MX
can be extracted from water with more
that 40% efficiency, it is more easily iden-
tified when not methylated or derivatized.
Both GC/FT-IR and GC/MS are capable
of identifying MX in the very low nanogram
range. MX is thermally stable below about
260°C, and can be chromatographed eas-
ily with maximum oven and injector tem-
peratures below this level. When the best
analytical method for MX'has been deter-
mined, we will investigate the possibility pf
^o Printed on Recycled Paper
-------
MX (or related mutagenic compound) for-
mation on ozonation. The results of these
studies could have an important impact
on the consideration of alternatives to
chlorine disinfection.
Corollary investigations on the fate of a
MX-model compound indicate that the al-
kaline hydrolysis of this family is rapid.
Further studies in this area may suggest
procedures that could be incorporated in
treatment and delivery systems to de-
crease the mutagenicity of drinking water.
Direct aqueous injection GC/FT-IR has
been shown to be a feasible way of ana-
lyzing the water fractions of DOM chlori-
nation studies, which have been neglected
in most byproduct identification schemes.
The use of this technique with fresh
samples could be very informative. There
is a possibility that the remaining 40 to
70% of drinking water mutagenicity (that
not due to MX or other identified com-
pounds) could be due to extremely hydro-
philic compounds not identified because
they have not been extracted from water.
This technique offers a convenient, im-
mediately applicable way of investigating
this question.
Objectives and
Accomplishments
1) We ran pure standards of five com-
pounds (MX, methylated MX [MX-
OMe], mucochloric acid [MCA],
mucobromic acid [MBA], and 2,4-
[3H,5H]-furandione [24FD]) on both
our GC/MS and GC/FT-IR instru-
ments to add their spectra to our
libraries and determined their GC
retention times. We chose the latter
three compounds to serve as MX
models.
2) We conducted a concentration study
and generated a standard curve for
MX on the GC/FT-IR. In contrast to
GC/MS, detection limits for GC/FT-
IR vary greatly for different classes
of compounds. We, therefore,
wanted to determine the minimum
identifiable quantity (MIQ) for MX on
our GC/FT-IR instrument. MIQ has
been defined as the minimum quan-
tity that must be injected to result in
a spectral match that has the cor-
rect compound identification in the
top five spectral matches.
3) We carried out a study of the ther-
mal stability of MX. The GC/FT-IR
response, as a function of heated
splitless injector port temperature,
, was__o_bseryed for_separate, equal-,
volume injections to determine the
temperature at which substantial
degradation occurred. The tentative
identity of the thermal degradation
product was determined by GC/MS.
4) The GC/FT-IR detector response for
a given injected quantity of MX was
compared to that of an injection of
an equal quantity of MX that was
methylated (MX-OMe) and extracted.
The goal of this experiment was to
determine to what degree methyla-
tion facilitates GC/FT-IR detection of
MX.
5) Several extracts of DOM chlorina-
tions were analyzed by GC/MS and
GC/FT-IR for MX and related com-
pounds. One extract was from a
sample that was methylated and re-
acted with PFBOA. The others were
from samples that were solvent ex-
tracted after chlorination.
6) The approximate extraction efficiency
of MX and MCA from water was
determined for a number of organic
solvents.
7) An auxiliary objective of this research
was to identify the hydrophilic com-
pounds that are left in the aqueous
phase of chlorinated DOM, after all
extractions have been performed.
Although extensive derivatization and
extraction procedures have been
developed for these types of
samples, to our knowledge no one
has ever published identifications
based on a direct analysis of the
aqueous fraction. We are also inter-
ested in developing a direct aque-
ous analysis method for MX, as an
.alternative to extraction, methylation,
or derivatization methods. In a pre-
liminary feasibility study, we obtained
the aqueous fraction from a chlori-
nated DOM sample and analyzed it
by direct aqueous injection (DAI) GC/
FT-IR.
8) Another auxiliary objective o1 Xhis re-
search was to determine the fate of
MX in aqueous media over time pe-
riods characteristic of holding times
in water supply distribution systems.
, We would like to determine whether
MX is transformed via hydrolysis,
and, if so, to what products. MX
recently has been shown to degrade
in the presence of excess chlorine.
These are obviously important is-
sues in determining the level of MX
likely to be at the tap, depending on
pH, residual chlorine, etc. Preliminary
alkaline hydrolysis experiments have
been performed with MCA, as a
model for MX.
U.S. GOVERNMENT PRINTING OFFICE: 1991/548-028/20202
-------
-------
Timothy W. Collette (also the EPA Project Officer, see below) and John M.
McGuIre are with the Environmental Research Laboratory, l/.S. Environmental
Protection Agency, Athens, GA 30613-7799; Russell F. Christman is with the
School of Public Health, University of North Carolina, Chapel Hill, NC 27955;
Cheryl Trusty is with Technology Applications, Inc., c/o U.S. Environmental
Protection Agency, Athens, GA.
The complete report, entitled "Multispectral Identification of Potentially Hazardous
Byproducts ofOzonation and Chlorination: Part I, Studies of Chromatographic
and Spectroscopic Properties of MX," (Order No. PB91-161 703/AS; Cost:
$17.00 subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Athens, GA 30613-7799
United States
Environmental Protection
Agency
Center for Environmental
Research Information
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/600/S4-91/004
------- |