&EPA
United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
P.O. Box 93478
Las Vegas NV 89193-3478
June 1993
OFFICE OF RESEARCH AND DEVELOPMENT
TECHNOLOGY SUPPORT PROJECT
Field-Portable Scanning
Spectrofluorometer
AnEMSL-LV
Innovative
Technology
The Need:
Field-portable instru-
ments are available for
the qualitative and
quantitative evaluation
of volatile organic
compounds and non-
volatile inorganic
elements. Compounds
that fall between these
volatility extremes have
received less attention
in recent years. And
yet these compounds
comprise a surprising
number of important
contamination catego-
ries at Superfund and
RCRA sites.
Polyaromatic hydrocar-
bons (PAHs) in com-
plex mixtures such as
oils, creosotes, and tars
are found on numerous
hazardous waste sites
and, because of their
high molecular weight,
present special chal-
lenges to analytical
chemists and instru-
ment developers.
These compounds have
relatively high lumines-
cence yields and,
therefore, can be readily
measured by spectroflu-
orometry.
A recent technology
that is in the production
prototype stage is the
Field-Portable Scanning
Spectrofluorometer
(FPSS). It is a light-
weight battery-operated
instrument that has
shown early promise as
a screening device for
petroleum oils, PAHs
and, especially, creo-
sotes.
Creosote (wood preser-
vation) and coal gasifi-
cation sites are wide-
spread, especially in the
southeastern United
States. These are
complex sites that
usually have various
PAHs in addition to the
creosotes. These
compounds are cur-
rently quantified by gas
chromatography but
their tarlike composition
makes them difficult to
detect and destructive
to columns and detec-
tors. The development
of a field-portable
instrument to rapidly
identify and quantify
PAH mixtures, such as
creosotes, oils, as-
phalts, or coal tars is
an important step in
filling a field analytical
niche.
The FPSS prototype is
ready for field demon-
stration and compara-
tive studies. It is
anticipated that the
FPSS will provide a
more rugged and less
expensive alternative to
traditional methods for
screening PAHs.	
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The Use:
Scientists working at
the Environmental
Monitoring Systems
Laboratory-Las Vegas
have performed labora-
tory evaluations of the
battery-operated FPSS
developed by T. Vo-
Dinh and his co-work-
ers at Oak Ridge
National Laboratory.1'23
Table 1 shows the
physical characteristics
of the instrument.
The FPSS can perform
emission and synchro-
nous wavelength
scans. In the emission
mode, relatively low
detection limits are
achieved (Table 2).
The emission mode is
useful for the determi-
nation of total PAHs or
in identifying and classi-
fying oils. In the syn-
chronous mode both
the excitation and
emission monochroma-
tors are scanned simul-
taneously with a con-
stant wavelength offset.
The advantage to syn-
chronous mode is that it
separates spectra of
compounds with a
different number of
fused rings, sharpens
spectra, and allows the
relative amount of
various PAH classes to
be quantified.
The FPSS consists of
three parts: a small
Table 1. Physical Characteristics of the Field-
Portable Scanning Spectroltuorometer
SIZE
WEIGHT
Instrument
Battery Pack
48x40x21 cm
(18.5 x 11.5x8")
31 K18 x 15 cm
(12x7x6")
11.5 kg
11.0 kg
suitcase-sired instru-
ment that houses the
optics and electronics,
a battery pack, and a
lap top computer used
for instrument control,
data storage and
analysis. The spectra!
coverage of the instru-
ment is 210-650 nm.
The instrument param-
eters are chosen by the
operator who uses the
computer to control the
instrument.
The FPSS can be oper-
ated two ways: using a
standard fluorescence
cuvette cell or a bifur-
cated optical fiber. The
optical fiber attachment
is 2-meter long and
allows direct screening
of water samples. The
cuvette can be used
with liquid samples or
extracts of soils. When
the optical fiber attach-
ment is used, care must
be taken to avoid inter-
ference from light. This
can be done by cover-
ing the sampling area
with a black cloth.
Table 2. Limit of Detection (S/N = 3)
SYNCHRONOUS EMISSION SYNCHRONOUS
(cuvette) tcjv&tte) ,'ftai;
Petkin Elmer LS50
0.17*
0.02
24
(laboratory instrument)



FPSS prototype
3.5
0.55
1
' All concentrations ng/mL of anthracene
The Limits:
Some areas of concern
exist relative to the
successful operation of
the FPSS in a field
situation. The rugged-
ness of the optical
components is crucial
to the in situ applicabil-
ity of the system. The
unit was shipped from
Oak Ridge National
Laboratory to the
EMSL-LV without
affecting the optical
alignment or electron-
ics. The instrument has
been demonstrated to
withstand norma!
handling in the labora-
tory. The instrument is
(continued on next page)

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The Limits:
(continued)
The Status:
ready to be demon-
strated at a hazardous
waste site.
The FPSS is particu-
larly suited to the
classification or identifi-
cation of oils or PAH
compounds. It can also
be used with site-
specific standards to
quantify total oils or
PAHs. It can be used to
determine relative
amounts of the PAH
classes present. In
rare instances, like
spills of solvents or
PAHs with very high
fluorescent yields and
sharp structures such
as benzo-(a)pyrene, it
can be used to detect
and quantify identified
PAHs. There is greater
spectral separation
capability when the
instrument is operated
in synchronous mode
but lower detection
limits can be achieved
using the emission
mode.
Laboratory evaluations
and research efforts
have resulted in a draft
fluorescence method
for the analysis of
PAHs which is in the
final stages of accep-
tance by the American
Society for Testing and
Materials. A compari-
son of the optical fiber
mode and the standard
cuvette mode was per-
formed on samples of
anthracene in metha-
nol. This study showed
the cuvette mode to be
2-3 times more sensi-
tive than the optical
fiber mode.
Synchronous lumines-
cence has been dem-
onstrated to be useful
in characterizing crude
and fuel oils.4 The
technique can be used
to produce spectral
fingerprints for the
identification of oil
contamination types
and sources. The
FPSS proved its ability
in a study comparing
samples from an oil
spill with samples of the
source oil which were
provided by the U.S.
Coast Guard.
The FPSS has shown
considerable promise
for the classification
and quantitation of PAH
compounds and oily
mixtures. The next
step is to take the
portable instrument to a
hazardous waste site
where it can be evalu-
ated against standard
methods in a well-
planned experimental
design. The develop-
ment of the FPSS was
sponsored by the
EMSL-LV and commer-
cialization is being
planned.
References:	1 T.Vo-Dinh, "Synchronous Excitation Spectroscopy" in Modern Fluores-
cence Spectroscopy, Vol. 4, Edited E.L. Wehry, Plenum Press, New York,
1981, pp. 167-192.
2	T. Vo-Dinh, "Synchronous Luminescence Spectroscopy: Methodology and
Applicability", Applied Spectroscopy, Vol. 36, 576,1982.
3	J.P. Alarie, Vo-Dinh, T., Miller, G., M.N. Ericson, S.R. Maddox, W. Watts,
D. Eastwood, R.L. Lidberg, and M. Dominguez, "Development of a Battery-
Operated Portable Synchronous Luminescence Spectrofluorometer", in
press, (Review of Scientific Instruments).
4	K.J. Siddiqui, Lidberg, R.L., Eastwood, D., and Gibson, G., "Expert Sys-
tems for Classification and Identification of Waterborne Petroleum Oils",
Monitoring Water in the 1990s, Meeting New Challenges, ASTM STP 1102,
J.R. Hall and G.D. Glysson, Editors, American Society for Testing and
Materials, Philadelphia, 1991.

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The Contacts	For further information about synchronous luminescence spectroscopy,
contact:
Mr. William H. Engelmann, Manager
Advanced in Situ Monitoring Program
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2664
For information about evaluating the FPSS at a hazardous waste site
(Superfund or RCRA), contact:
Mr. Ken Brown, Manager
Technology Support Center
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
P.O. Box 93478
Las Vegas, NV 89193-3478
(702) 798-2270
The Technology Support Center fact sheet series is developed by Clare L. Gerlach,
Lockheed Environmental Systems & Technologies Company, Las Vegas
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