ASTM D5986-96(2006)
(Test Method)Standard Test Method for Determination of Oxygenates, Benzene, Toluene, C8-C 12 Aromatics and Total Aromatics in Finished Gasoline by Gas Chromatography/Fourier Transform Infrared Spectroscopy
Standard Test Method for Determination of Oxygenates, Benzene, Toluene, C<inf>8</inf>-C<inf> 12</inf> Aromatics and Total Aromatics in Finished Gasoline by Gas Chromatography/Fourier Transform Infrared Spectroscopy
SIGNIFICANCE AND USE
Test methods to determine oxygenates, benzene, and the aromatic content of gasoline are necessary to assess product quality and to meet new fuel regulations.
This test method can be used for gasolines that contain oxygenates (alcohols and ethers) as additives. It has been determined that the common oxygenates found in finished gasoline do not interfere with the analysis of benzene and other aromatics by this test method.
SCOPE
1.1 This test method covers the quantitative determination of oxygenates: methyl-t-butylether (MTBE), di-isopropyl ether (DIPE), ethyl-t-butylether (ETBE), t-amylmethyl ether (TAME), methanol (MeOH), ethanol (EtOH), 2-propanol (2-PrOH), t-butanol (t-BuOH), 1-propanol (1-PrOH), 2-butanol (2-BuOH), i-butanol (i-BuOH), 1-butanol (1-BuOH); benzene, toluene and C8-C12 aromatics, and total aromatics in finished motor gasoline by gas chromatography/Fourier Transform infrared spectroscopy (GC/FTIR).
1.2 This test method covers the following concentration ranges: 0.1-20 volume % per component for ethers and alcohols; 0.1-2 volume % benzene; 1-15 volume % for toluene, 10-40 volume % total (C6-C12) aromatics.
1.3 The method has not been tested by ASTM for refinery individual hydrocarbon process streams, such as reformates, fluid catalytic cracking naphthas, etc., used in blending of gasolines.
1.4 SI units of measurement are preferred and used throughout this test method.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D5986–96 (Reapproved 2006)
Standard Test Method for
Determination of Oxygenates, Benzene, Toluene, C –C
8 12
Aromatics and Total Aromatics in Finished Gasoline by Gas
Chromatography/Fourier Transform Infrared Spectroscopy
This standard is issued under the fixed designation D5986; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope D4052 Test Method for Density and Relative Density of
Liquids by Digital Density Meter
1.1 This test method covers the quantitative determination
D4057 Practice for Manual Sampling of Petroleum and
of oxygenates: methyl-t-butylether (MTBE), di-isopropyl ether
Petroleum Products
(DIPE), ethyl-t-butylether (ETBE), t-amylmethyl ether
D4307 Practice for Preparation of Liquid Blends for Use as
(TAME), methanol (MeOH), ethanol (EtOH), 2-propanol (2-
Analytical Standards
PrOH), t-butanol (t-BuOH), 1-propanol (1-PrOH), 2-butanol
(2-BuOH), i-butanol (i-BuOH), 1-butanol (1-BuOH); benzene,
3. Terminology
toluene and C –C aromatics, and total aromatics in finished
8 12
3.1 Definitions of Terms Specific to This Standard:
motor gasoline by gas chromatography/Fourier Transform
3.1.1 aromatics—refers to any organic compound contain-
infrared spectroscopy (GC/FTIR).
ing a benzene or naphthalene ring.
1.2 This test method covers the following concentration
3.1.2 calibrated aromatic component—in this test method,
ranges: 0.1–20 volume % per component for ethers and
refers to the individual aromatic components which have a
alcohols; 0.1–2 volume % benzene; 1–15 volume % for
specific calibration.
toluene, 10–40 volume % total (C –C ) aromatics.
6 12
3.1.3 cool on-column injector—in gas chromatography,a
1.3 The method has not been tested by ASTM for refinery
direct sample introduction system which is set at a temperature
individual hydrocarbon process streams, such as reformates,
at or below the boiling point of solutes or solvent on injection
fluid catalytic cracking naphthas, etc., used in blending of
and then heated at a rate equal to or greater than the column.
gasolines.
Normally used to eliminate boiling point discrimination on
1.4 SIunitsofmeasurementarepreferredandusedthrough-
injectionortoreduceadsorption,orboth,onglasslinerswithin
out this test method.
injectors. The sample is injected directly into the head of the
1.5 This standard does not purport to address all of the
capillary column tubing or retention gap.
safety concerns, if any, associated with its use. It is the
3.1.4 Gram-Schmidt chromatogram—a nonselective sum-
responsibility of the user of this standard to establish appro-
mation of total intensity from a spectral scan per unit time
priate safety and health practices and determine the applica-
which resembles in profile a flame ionization detector chro-
bility of regulatory limitations prior to use.
matogram.
2. Referenced Documents 3.1.5 retention gap—in gas chromatography, refers to a
2 deactivated precolumn which acts as a zone of low retention
2.1 ASTM Standards:
power for reconcentrating bands in space. The polarity of the
D1298 Test Method for Density, Relative Density (Specific
precolumn must be similar to that of the analytical column.
Gravity), or API Gravity of Crude Petroleum and Liquid
3.1.6 selective wavelength chromatogram (SWC)—in this
Petroleum Products by Hydrometer Method
test method, refers to a selective chromatogram obtained by
summing the spectral intensity in a narrow spectral wavelength
This test method is under the jurisdiction of ASTM Committee D02 on
or frequency range as a function of elution time which is
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
unique to the compound being quantitated.
D02.04.0L on Gas Chromatography Methods.
3.1.7 uncalibrated aromatic component—in this test
Current edition approved Nov. 1, 2006. Published January 2007. Originally
approved in 1996. Last previous edition approved in 2001 as D5986 – 96 (2001).
method,referstoindividualaromaticsforwhichacalibrationis
DOI: 10.1520/D5986-96R06.
not available and whose concentrations are estimated from the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
response factor of a calibrated aromatic component.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5986–96 (2006)
3.1.8 wall coated open tubular (WCOT)—a type of capil-
lary column prepared by coating or bonding the inside wall of
the capillary with a thin film of stationary phase.
4. Summary of Test Method
4.1 A gas chromatograph equipped with a methylsilicone
WCOT column is interfaced to a Fourier transform infrared
spectrometer.The sample is injected through a cool on-column
injector capable of injecting a small sample size without
overloading the column.
4.2 Calibration is performed using mixtures of specified
pure oxygenates and aromatic hydrocarbons on a mass basis.
Volume % data is calculated from the densities of the indi-
vidual components and the density of the sample. Multipoint
FIG. 1 Light-Pipe GC/FTIR System
calibrations consisting of at least five levels and bracketing the
concentration of the specified individual aromatics is required.
Unidentified aromatic hydrocarbons present which have not
been specifically calibrated for are quantitated using the
response factor of 1,2,3,5-tetramethylbenzene and summed
with the other calibrated aromatic components to obtain a total
aromatic concentration of the sample.
4.3 Specified quality control mixture(s) are analyzed to
monitor the performance of the calibrated GC/FTIR system.
5. Significance and Use
5.1 Test methods to determine oxygenates, benzene, and the
aromatic content of gasoline are necessary to assess product
quality and to meet new fuel regulations.
5.2 This test method can be used for gasolines that contain
oxygenates (alcohols and ethers) as additives. It has been
determined that the common oxygenates found in finished
gasolinedonotinterferewiththeanalysisofbenzeneandother
aromatics by this test method.
6. Apparatus
FIG. 2 Vapor Phase Spectrum of Benzene
6.1 Gas Chromatograph:
6.1.1 System equipped with temperature programmable gas
7. Reagents and Materials
chromatograph suitable for cool-on-column injections. The
7.1 Carrier Gas—Helium and hydrogen have been used
injector must allow the introduction of small (for example, 0.1
successfully. The minimum purity of the carrier gas used must
µL) sample sizes at the head of the WCOT column or a
be 99.85 mole %. Additional purification using commercially
retention gap. An autosampler is mandatory.
available scrubbing reagents is recommended to remove trace
6.1.2 WCOT column containing a methylsilicone stationary
oxygen which may deteriorate the performance of the GC
phase which elutes the aromatic hydrocarbons according to
WCOT column.
their boiling points.Acolumn containing a relatively thick film
7.2 Dilution Solvents—n-heptane and methylbenzene (tolu-
of stationary phase, such as 4 to 5 µm, is recommended to
ene) used as a solvent in the preparation of the calibration
prevent column sample overload.
mixture. Reagent grade. All at 99 % or greater purity. Free
6.2 FTIR Spectrometer:
from detectable oxygenates and aromatics which may interfere
6.2.1 This test method requires a light-pipe GC/FTIR sys-
with the analysis.
tem (Fig. 1). No data have been acquired with matrix-isolation
7.2.1 Toluene should be used as a solvent only for the
or other deposition type systems.
preparation of C + components and must be free from inter-
6.2.2 The spectrometer must be equipped with a mercury-
fering aromatics. (Warning—The gasoline samples and sol-
cadmium-telluride(MCT)detectorcapableofdetectingfromat
vents used as reagents such as heptane and toluene are
least 4000 cm-1 to 550 cm-1.
flammable and may be harmful or fatal if ingested or inhaled.
6.2.3 The lower limit of 550 cm-1 is necessary for the Benzene is a known carcinogen. Use with proper ventilation.
accurate determination of benzene. Fig. 2 gives an acceptable Safety glasses and gloves are required while preparing samples
infrared spectra of benzene. and standards.)
D5986–96 (2006)
TABLE 2 GC/FTIR Aromatic Hydrocarbons Calibration
7.3 Internal Standard—1,2-dimethoxyethane (DME) or
Components (Calibrated Aromatic Components)
deuterated compounds, or both, have been used successfully.A
Compound CAS No.
single internal standard such as DME may be used. If other
Benzene 71-43-2
internal standards are used, a narrow selective wavelength
Methylbenzene 108-88-3
range must be determined to generate a SWC which yields no
Ethylbenzene 100-41-4
interference from other components in the sample.
1,3-Dimethylbenzene 108-38-3
7.4 Liquid Nitrogen, supplied from low pressure dewar. 1,4-Dimethylbenzene 106-42-3
1,2-Dimethylbenzene 95-47-6
Required for cooling of the MCT detector. Dewar may be
(1-Methylethyl)-benzene 98-82-8
connected through an electronic solenoid to the MCT cooling
Propyl-benzene 103-65-1
1-methyl-3-ethylbenzene 620-14-4
reservoir for unattended operation. (Warning—Helium and
1-methyl-4-ethylbenzene 622-96-8
hydrogen are supplied under high pressure. Hydrogen can be
1,3,5-trimethylbenzene 108-67-8
explosive and requires special handling. Hydrogen monitors
1-methyl-2-ethylbenzene 611-14-3
1,2,4-trimethylbenzene 95-63-6
that automatically shut off supply to the GC in case of serious
1,2,3-trimethylbenzene 526-73-8
leaks are available from GC supply manufacturers.)
Indan 496-11-7
7.5 Spectrometer Purge Gas,N dry air has not been tested,
2 1,4-diethylbenzene 105-05-5
Butylbenzene 104-51-8
but should be adequate.
1,2-Diethylbenzene 135-01-3
1,2,4,5-Tetramethylbenzene 95-93-2
NOTE 1—The FTIR spectrometer can be protected by installing appro-
1,2,3,5-Tetramethylbenzene 527-53-7
priate filters to remove volatile oils or contaminants that may be present
Naphthalene 91-20-3
in commercial low quality nitrogen supplies.Aliquid nitrogen dewar may
2-methyl-naphthalene 91-57-6
be used as a source for the nitrogen purge.
1-methyl-naphthalene 90-12-0
7.6 Standards for Calibration and Identification, all at 99 %
or greater purity (Table 1 and Table 2). If reagents of high
purity are not available, an accurate assay of the reagent must
be performed using a properly calibrated GC or other tech- 8.3 After the sample is prepared for analysis with internal
standard(s), chill the sample and transfer to an appropriate
niques. The concentration of the impurities which overlap the
other calibration components must be known and used to autosampler vial with minimal headspace. Re-chill the remain-
derofthesampleimmediatelyandprotectfromevaporationfor
correct the concentration of the calibration components. Be-
cause of the error that may be introduced from impurity further analyses, if necessary.
corrections, the use of only high purity reagents is strongly
recommended. Standards are used for calibration as well for 9. Calibration Procedure
establishing the identification by retention time in conjunction
9.1 Preparation of Calibration Standards—Prepare multi-
with spectral match.
component calibration standards using the compounds listed in
Table 1 and Table 2 by mass according to Practice D4307.
8. Sampling
Prepare calibration solutions as described in 9.1-9.1.4 for each
8.1 Make every effort to ensure that the sample is represen-
set.Adjusttheseconcentrations,asnecessary,toensurethatthe
tative of the fuel source from which it is taken. Follow the
concentrations of the components in the actual samples are
recommendations of Practice D4057 or its equivalent when
bracketed by the calibration concentrations. Solid components
obtaining samples from bulk storage or pipelines. Sampling to
are weighed directly into the flask or vial. The specified
meet certain regulatory specifications may require the use of
volumes of each calibration component are weighed into 100
specific sampling procedures. Consult appropriate regulations.
mL volumetric flasks or 100 mL septum capped vials. Prepare
8.2 Take appropriate steps to minimize the loss of light
a calibration standard as follows. Cap and record the tare
hydrocarbons from the gasoline sample while sampling and
weight of the 100 mL volumetric flask or vial to 0.1 mg.
duringanalyses.Uponreceiptinthelaboratorychillthesample
Remove the cap and carefully add components to the flask or
in its original container to 0 to 5°C (32 to 40°F) before and
vial starting with the least volatile component. Cap the flask
after a sample is obtained for analysis.
and record the net mass (Wi) of the aromatic component added
to0.1mg.Repeattheadditionandweighingprocedureforeach
TABLE 1 GC/FTIR Oxygenates Calibration Components
component. Similarly add the internal standard and record its
Compound CAS
netmass(Ws)to0.1mg.Storethecappedcalibrationstandards
Methyl-t-butyl ether (MTBE) 1634-04-4
in a refrigerator at 0 to 5°C (32 to 40°F) when not in use.
Ethyl-t-butyl ether (ETBE) 637-92-3
Methyl-t-amyl ether (TAME) 994-05-8
NOTE 2—Mix all calibration solutions for at least 30 s on a Vortex
Di-isopropyl ether (DIPE) 108-20-3
mixer after preparation or equivalent. Highly precise sample robotic
Methanol 67-56-1
Ethanol 64-17-5 sample preparation systems are available commercially. These systems
2-Propanol 67-63-0
may be used provided that the results for the quality control reference
t-Butanol 75-65-0
material (Section 11) are met when prepared in this manner.
1-Propanol 71-23-6
2-Butanol 15892-23-6 9.1.1 Ethers and Alcohols:
Isobutanol 78-83-1
9.1.1.1 Three sets of at least six calibration levels each
1-Butanol 71-36-3
(eighteen total solutions) are prepared bracketing the 0 to 20
1,2-dimethoxyethane (DME) (Internal Standard) 110-71-4
volume % range. Set 1: for MTBE, DIPE, ETBE, TAME; Set
D5986–96 (2006)
2: MeOH, EtOH, 2-PrOH, t-BuOH; and Set 3: 1-PrOH, 9.1.2.3 For toluene (T): 1, 3, 5, 7, 10, 15 mL aliquots are
2-BuOH, i-BuOH, 1-BuOH. added to respective flasks above (that is, least concentrated
9.1.1.2 For each above Set: 1, 3, 5, 10, 15, and 20 mL toluene is in solution with least concentrated ethylbenzene and
aliquotsofeachcomponentarepipettedintorespective100mL xylenes-EX) while accurately recording the masses.
volumetric flasks or vials while accurately recording the 9.1.2.4 For benzene (B): 0.10 mL, 0.30 mL, 0.50 m
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.