ASTM E2143-01

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Designation: E 2143 – 01
Standard Practice for
Using Field-Portable Fiber Optics Synchronous
Fluorescence Spectrometer for Quantification of Field
Samples for Aromatic and Polycyclic Aromatic
Hydrocarbons
This standard is issued under the fixed designation E 2143; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope cyclic Aromatic Hydrocarbon Mixtures or Petroleum Oils
in Water
1.1 This test method provides a rapid method for the
E 131 Terminology and Symbols Related to Molecular
screeningofenvironmentalsamplesforaromatichydrocarbons
Spectroscopy
(AHs) and polycyclic aromatic hydrocarbons (PAHs). The
E 388 Test Method for Spectral Bandwidth and Wavelength
screening takes place in the field and provides immediate
Accuracy of Fluorescence Spectrometers
feedback on limits of contamination by substances containing
E 578 TestMethodforLinearityofFluorescenceMeasuring
AHs and PAHs. Quantification is obtained by the use of
Systems
appropriately characterized, site-specific calibration curves.
E 579 Test Method for Limit of Detection of Fluorescence
Remote sensing by use of optical fibers is useful for accessing
of Quinine Sulfate
difficult to reach areas or potentially dangerous materials or
situations. When contamination of field personnel by danger-
3. Terminology
ous materials is a possibility, use of remote sensors may
3.1 For definitions of terms used in this test method refer to
minimize or eliminate the likelihood of such contamination
Terminology D 1129 and E 131.
taking place.
1.2 This test method is applicable toAHs and PAHs present
4. Summary of Test Method
in samples extracted from soils or in water. This test method is
4.1 This test method consists of extracting the AHs and
applicable for field screening or, with an appropriate calibra-
PAHs from soil samples or preparation of water samples
tion, quantification of total AHs and PAHs.
followed by synchronous fluorescence analysis with a field-
1.3 This standard does not purport to address all of the
portable instrument. The samples require serial dilutions of
safety concerns, if any, associated with its use. It is the
samples to establish a linear response.These measurements are
responsibility of the user of this standard to establish appro-
made using standard fluorescence cuvettes. While some opti-
priate safety and health practices and determine the applica-
mization of selectivity can be accomplished by varying the
bility of regulatory limitations prior to use.
wavelength difference between excitation and emission mono-
chromators, generally spectra generated from petroleum con-
2. Referenced Documents
taminants with a wavelength difference such as 6 or 18 nm
2.1 ASTM Standards:
2 provide good results and no preliminary spectra are required
D 1129 Terminology Related to Water
3 (see Test Method D 5412).
D 4489 Practice for Sampling of Waterborne Oils
4.2 Different soils have varying partition coefficients.
D 5412 Test Method for Quantification of Complex Poly-
Therefore, representative samples of a subset of the extracts or
the water samples should be analyzed by gas chromatography
(GC) or other appropriate methods. The purpose is to establish
This practice is under the jurisdiction of ASTM Committee E13 on Molecular a site-specific calibration curve to be used for quantification of
Spectroscopy and is the direct responsibility of Subcommittee E13.09 on Optical
total AHs and PAHs in the environmental samples of interest.
Fibers and Wave Lengths.
Current edition approved April 10, 2001. Published July 2001.
Annual Book of ASTM Standards, Vol 11.01.
3 4
Annual Book of ASTM Standards, Vol 11.02. Annual Book of ASTM Standards, Vol 03.06.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959, United States.
E2143–01
4.3 When desirable, determination of AHs and PAHs may both excitation and emission spectrum measurements and
be made remotely using an optical fiber. capable of scanning both monochromators at a constant speed
with a constant wavelength offset between them for synchro-
5. Significance and Use
nous scanning. The bandwidth of the monochromators should
be less than one half the wavelength offset between the
5.1 This technique is designed for on-site rapid screening
monochromators or smaller. The spectrometer should be ca-
and characterization of environmental soil and water samples
pable of remote sensing via optic fiber. The detector should be
resulting in significant cost savings for environmental reme-
a photomultiplier tube or a device with similar sensitivity and
diation projects. Remote analysis can be made with optical
response time. Occasionally field work requires the spectrom-
fibers when situations warrant or demand use of this option.
eter to be battery powered. The instrument should meet the
5.2 Quantification of total AHs and PAHs in these environ-
specifications in Table 1.
mental samples is accomplished by having a subset of the
7.2 Excitation Source—A pulsed (9.9 W) Xenon lamp or
samples analyzed by an alternate technique and generating a
other source having sufficient intensity throughout the ultra-
site-specific calibration curve.
violet and visible regions can be used.
5.3 Synchronous fluorescence provides sufficient spectral
7.3 Cuvette Sample Holder—Sample holders should be
information to characterize the AHs and PAHs present as
fabricated to hold commercially available, fluorescence-free,
benzene, toluene, ethylbenzene and xylene(s) (BTEX), the
fused silica cuvettes.
aromatic portion of total petroleum hydrocarbons (TPH), or
7.4 Optical Fiber Holder—A stage that allows correct
large aromatic ring systems up to at least seven fused rings,
positioning of the optical fiber with respect to the emission and
such as might be found in creosote.
excitation monochromators. The device may also be used to
optically match each fiber and the respective monochromator.
6. Interferences
7.5 ComputerSystem—The instrument should be interfaced
6.1 Thesynchronousfluorescencespectrumcanbedistorted
to a computer system that is compatible with the instrument
or quantification may be affected if there is a contaminant
and has suitable software for spectral data manipulation.
present that produces a synchronous peak in the same vicinity
7.6 Cuvette—A standard 12 by 12 by 31 mm fluorescence-
as the material of interest. Often spectroquality solvents
free fused silica cuvette. Four sides of the cuvette should be
contain impurities that produce background signals. Solvent
polished.
blanks should be used to verify a low fluorescence background
7.7 Optical Fiber—Fused silica fiber (preferably a high
so the background can be subtracted from the sample’s
hydroxide) is required for transmission of the ultraviolet
spectrum.
wavelengths required for accurate spectroscopic analysis. In
6.2 There are naturally occurring compounds that fluoresce,
general, this material has good thermal characteristics, can be
which may interfere with the detection of petroleum com-
obtained with low fluorescence background, and is readily
pounds,presentinthesample.Humicacidfromleafmoldisan
available commercially.
example of such a compound. Its strongest emission occurs in
7.8 Glassware—A 10 mL and 2 mL disposable pipet, both
the near ultraviolet range.
marked with 0.1 mL gradations. A glass disposable test tube,
6.3 Absorption of the exciting light by the sample itself
capable of holding volumes of liquid greater than 15 mL. The
(self-filtering effect) produces erroneous results. Analysis of
test tube caps should be polytetrafluoroethylene lined to reduce
serial dilutions of the sample detects this effect and ensures an
potential contamination.
accurate analysis is made. Once linearity is established, then
7.9 Scale—Aportablescalecapableofmeasuring2gofsoil
integration of the spectrum produces accurate results.
to the nearest 0.1 g.
6.4 Certain solvents used for extraction of the soil samples
7.10 Centrifuge—A portable centrifuge, capable of holding
could quench or absorb the fluorescence and raise the limit of
the test tubes described in 7.8.
detection. Care should be taken to avoid halogenated solvents
7.11 Shaker—A portable shaker, capable of mixing the soil
or solvents containing other quenchers. The user of this test
and solvent in the test tubes described in 7.8.
method should bear this in mind when selecting an appropriate
solvent.
NOTE 1—Storage of samples in improper containers, such as plastics TABLE 1 Desirable Performance Standards of a Field Portable
Fluorescence Spectrometer
other than polytetrafluoroethylene (or TFE-fluorocarbon), may result in
contamination.
Characteristic Desirable Range Typical
NOTE 2—This test method is normally used without an internal stan-
Monochromator
dard due to possible interference by the internal standard.
Bandwidth 1–5 nm 3 nm
Wavelength accuracy 6 0.5–2 nm 6 1.0 nm
6.5 Certain optical fibers may generate a fluorescence back-
Reproducibility 6 0.1– 1% 6 0.2%
ground. These should be avoided whenever possible. If they
must be used, a background spectrum should be generated and Interface
Data collection computerized laptop PC
subtracted from any samples measured.
Instrument control control and data
7. Apparatus Source
Broad band 200–1000 nm Xenon lamp
7.1 Fluorescence Spectrometer—An instrument recording
Low-power consumption 5–75 W 10 W
in the spectral range of at least 250 to 650 nm is required for
E2143–01
7.12 Filter Apparatus—A syringe with disposable 100-µm 11. Procedure
glass detachable filters.
11.1 Water Samples—Analyze the water sample over an
appropriate wavelength region using a synchronous scan with
8. Reagents and Materials
a wavelength offset between the monochromators of 18 nm.
8.1 Purity of Reagents—Spectroquality grade reagents Other wavelength offset between the monochromators values
should be used in all instances unless otherwise stated. may be used when appropriate.
8.2 Purity of Water—ASTM Grade 3 or Grade 4 water 11.1.1 Subtract the spectrum of a distilled water blank from
should be used. the spectrum of the water sample.
8.3 Solvents—Highpuritysolventsshouldbeused.Solvents 11.1.2 Integrate the area under the spectrum of the sample
should be of sufficient purity so as to not generate a back- over the appropriate wavelength region to determine the
ground fluorescence spectrum when analyzed as a blank. relative value.
Solvents such as hexane, cyclohexane and methylcyclohexane, 11.1.3 Determine if the sample is in the linear range. The
ethanol,methanol,etc.mustnotabsorbinthespectralregionof determination of linear range is done by performing a 1:1
interest. dilution. Subtract the spectrum of a distilled water blank from
the spectrum of the 1:1 dilution. Integrate the area under the
spectrum of the sample over the appropriate wavelength
9. Sampling and Sample Preparation
region. If the integrated value is half of the original value, then
9.1 Water Samples—Collect water samples in accordance
the sample is in the linear range; otherwise, perform subse-
with Practice D 4489, as applicable.
quent dilutions until the linear range is established.
9.1.1 If the water samples contain visible particles, then the
11.2 SoilSamples—Analyzethesoilsampleextractoverthe
samples may be either centrifuged or filtered depending on the
appropriate wavelength region using a synchronous scan with
nature of the particles. Large, dense particles can usually be
a wavelength offset between the monochromators of 18 nm.
centrifuged to the bottom of the sample container, while finer
11.2.1 Subtract the spectrum of a solvent blank from the
particles must be filtered. The water samples should be
spectrum of the soil sample.
centrifuged in the containers in which they are sampled, in
11.2.2 Integrate the area under the spectrum of the sample
order to avoid volatilization of the organic hydrocarbons. The
over the appropriate wavelength region to determine the
water samples should be filtered into the cuvette for analysis.
relative value.
9.1.2 Add approximately 2.5 mL of the water sample into
11.2.3 Determine whether the sample is in the linear range
the cuvette using a disposable pipet and place the cuvette into
according to 11.1.3.
the instrument sample holder.The sample is ready for analysis.
11.3 Quantitative Analysis—After several soil or water
9.2 Soil Samples—Collect the sample using accepted pro-
samples have been analyzed by the instrument, pick several
cedures already established by ASTM Committee D18.
samples representing a range of concentrations (at least three:
9.2.1 Obtain a representative 2-g soil sample from the
high, medium, and low) and include solvent blanks and
samplecontainer.Thesampleshouldbeweigheddirectlyinthe
samples of known composition. These samples should be
test tube.
analyzed by the laboratory using the appropriate method, such
9.2.2 Add 10 mL of the appropriate solvent to the soil
as total petroleum hydrocarbons using the Environmental
sample in the test tube using a disposable pipet.
ProtectionAgency (EPA), gasoline range organics (GRO), and
9.2.3 Shake the sample until greater than 90 % of the
diesel range organics (DRO) methods or total polycyclic
sampleissuspendedinthesolvent.Followthisshakingprocess
aromatic hydrocarbons. Many of the approved EPA methods
bycentrifugingthesampleinordertoseparatethesolventfrom
also include aliphatic hydrocarbons in the analysis. If the
the soil.
relative proportion of aromatic hydrocarbons to aliphatic
9.2.4 Pour the extract into a second test tube. At this point
hydrocarbons remains constant then the correlation graphs
some particles may be present in the extract, thus filtration will
described in 11.3.1 can be developed.
be required to remove them.
11.3.1 For each sample analyzed by the laboratory, plot the
9.2.5 If the quality check in 13.6 indicates a need for
laboratory concentration versus the instrument concentration
additional extraction, then the additional extraction will be
on a scatter plot.Apply a trend line to the data set and perform
performed at this time.
linear regression. The equation of the trend line can be used to
predict the value of future instrument analyses. For further
10. Preparation of Apparatus
information, see Ref (1)in Appendix X1.
10.1 Prior to mobilization for field use, set up and calibrate
the fluorescence spectrometer according to the manufacturer’s
12. Calculations
instructions and Test Methods E 388, E 578, and E 579. Once
12.1 Spectra collected may be smoothed prior to integra-
inthefield,includeinthec
...