ASTM D6277-07(2012)
(Test Method)Standard Test Method for Determination of Benzene in Spark-Ignition Engine Fuels Using Mid Infrared Spectroscopy
Standard Test Method for Determination of Benzene in Spark-Ignition Engine Fuels Using Mid Infrared Spectroscopy
SIGNIFICANCE AND USE
5.1 Benzene is a compound that endangers health, and the concentration is limited by environmental protection agencies to produce a less toxic gasoline.
5.2 This test method is fast, simple to run, and inexpensive.
5.3 This test method is applicable for quality control in the production and distribution of spark-ignition engine fuels.
SCOPE
1.1 This test method covers the determination of the percentage of benzene in spark-ignition engine fuels. It is applicable to concentrations from 0.1 to 5 volume %.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D6277 −07 (Reapproved 2012)
Standard Test Method for
Determination of Benzene in Spark-Ignition Engine Fuels
Using Mid Infrared Spectroscopy
This standard is issued under the fixed designation D6277; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope of Petroleum and Petroleum Products
E168Practices for General Techniques of Infrared Quanti-
1.1 This test method covers the determination of the per-
tative Analysis
centage of benzene in spark-ignition engine fuels. It is appli-
E1655 Practices for Infrared Multivariate Quantitative
cable to concentrations from 0.1 to 5 volume %.
Analysis
1.2 The values stated in SI units are to be regarded as
E2056Practice for Qualifying Spectrometers and Spectro-
standard. No other units of measurement are included in this
photometers for Use in Multivariate Analyses, Calibrated
standard.
Using Surrogate Mixtures
1.3 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety and health practices and determine the applica-
3.1.1 multivariate calibration—a process for creating a
bility of regulatory limitations prior to use.
calibrationmodelinwhichmultivariatemathematicsisapplied
to correlate the absorbances measured for a set of calibration
2. Referenced Documents
samples to reference component concentrations or property
2.1 ASTM Standards:
values for the set of samples.
D1298Test Method for Density, Relative Density, or API
3.1.1.1 Discussion—The resultant multivariate calibration
Gravity of Crude Petroleum and Liquid Petroleum Prod-
modelisappliedtotheanalysisofspectraofunknownsamples
ucts by Hydrometer Method
to provide an estimate of the component concentration or
D4052Test Method for Density, Relative Density, and API
property values for the unknown sample.
Gravity of Liquids by Digital Density Meter
3.1.1.2 Discussion—Included in the multivariate calibration
D4057Practice for Manual Sampling of Petroleum and
algorithms are Partial Least Squares, Multilinear Regression,
Petroleum Products
and Classical Least Squares Peak Fitting.
D4177Practice for Automatic Sampling of Petroleum and
3.1.2 oxygenate—an oxygen-containing organic compound
Petroleum Products
which may be used as a fuel or fuel supplement, for example,
D4307Practice for Preparation of Liquid Blends for Use as
various alcohols and ethers.
Analytical Standards
D5769Test Method for Determination of Benzene,Toluene,
4. Summary of Test Method
and Total Aromatics in Finished Gasolines by Gas
4.1 Asampleofspark-ignitionenginefuelisintroducedinto
Chromatography/Mass Spectrometry
aliquidsamplecell.Abeamofinfraredlightisimagedthrough
D5842Practice for Sampling and Handling of Fuels for
the sample onto a detector, and the detector response is
Volatility Measurement
determined.Wavelengthsofthespectrum,thatcorrelatehighly
D5854Practice for Mixing and Handling of Liquid Samples
with benzene or interferences, are selected for analysis using
selective bandpass filters or by mathematically selecting areas
1 of the whole spectrum. A multivariate mathematical analysis
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
converts the detector response for the selected areas of the
D02.04.0F on Absorption Spectroscopic Methods.
spectrum of an unknown to a concentration of benzene.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
approved in 1998. Last previous edition approved in 2007 as D6277–07. DOI:
5. Significance and Use
10.1520/D6277-07R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1 Benzene is a compound that endangers health, and the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
concentration is limited by environmental protection agencies
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. to produce a less toxic gasoline.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6277−07 (2012)
5.2 This test method is fast, simple to run, and inexpensive. 7.2.1 Transmission Cells, shall have windows of potassium
bromide, zinc selenide, or other material having a significant
5.3 This test method is applicable for quality control in the
–1 –1
transmission from 712 cm to 660 cm . The cell path length
production and distribution of spark-ignition engine fuels.
of the transmission cell shall be 0.025 (6 0.005) mm. The use
of a wedged transmission cell with the same nominal path
6. Interferences
length is acceptable.
6.1 The primary spectral interferences are toluene and other
7.2.2 Attenuated Total Reflectance (ATR) Cells, shall have
monosubstituted aromatics. In addition, oxygenates can inter-
the following specifications:
fere with measurements made with filter apparatus. Proper
ATR element material ZnSe
choice of the apparatus, proper design of a calibration matrix,
beam condensing optics conical, non-focussing optics
and proper utilization of multivariate calibration techniques
integral to cell body
element configuration circular cross section with
can minimize these interferences.
coaxial conical ends
cone half angle 60°
7. Apparatus
element length 1.55 in.
element diameter 0.125 in.
7.1 Mid-IR Spectrometric Analyzer (of one of the following
angle of incidence at
types):
sample interface 53.8°
maximum range of
7.1.1 Filter-based Mid-IR Test Apparatus—The type of
incidence angles ± 1.5°
apparatus suitable for use in this test method minimally
standard absorbance
employesanIRsource,aninfraredtransmissioncelloraliquid
(1428 cm−1 band of acetone) 0.38 ± 0.02 AU
material of construction 316 stainless steel
attenuated total internal reflection cell, wavelength discrimi-
seals Chemraz or Kalraz o-rings
nating filters, a chopper wheel, a detector, anA-D converter, a
microprocessor, and a method to introduce the sample. The
8. Reagents and Materials (see Note 1)
frequencies and bandwidths of the filters are specified in Table
8.1 Standards for Calibration, Qualification, and Quality
1.
Control Check Standards—Use of chemicals of at least 99%
7.1.2 Fourier Transform Mid-IR Spectrometer—Thetypeof
purity, where available, for quality control checks is required
apparatus suitable for use in this test method employs an IR
when preparing samples. (Warning—These materials are
source,aninfraredtransmissioncelloraliquidattenuatedtotal
flammable and may be harmful if ingested or inhaled.)
internalreflectioncell,ascanninginterferometer,adetector,an
8.1.1 tert-Amyl methyl ether, TAME [994-05-8].
A-D converter, a microprocessor, and a method to introduce
8.1.2 Benzene [1076-43-3].
thesample.Thefollowingperformancespecifications(through
8.1.3 tert-Butyl ethyl ether, ETBE [637-92-3].
the ATR cell) must be met:
8.1.4 tert-Butyl methyl ether, MTBE [1634-04-4].
–1
scan range 4000 to 600 cm
–1
8.1.5 1,3 Dimethylbenzene (m-xylene).
resolution 4 cm
–1
S/N at 674 cm >300:1 RMS
8.1.6 Ethanol [64-17-5].
The signal to noise level will be established by taking a
8.1.7 Ethylbenzene [100-41-4].
singlebeamspectrumusingairornitrogenasthereferenceand
8.1.8 3–Ethyltoluene [620-14-4].
declaring that spectrum as the background. The background
8.1.9 Heavy aromatic/reformate petroleum stream (high
single beam spectrum obtained can be the average of multiple
boilingcut:IPBof150 65°CandEPof245 68°C)certified
FTIR scans, but the total collection time shall not exceed 60 s.
to contain less than 0.025% benzene (an absorbance of less
−1
If interference from water vapor or carbon dioxide is a
than 0.03 at 675 cm using a 0.2 mm cell and a baseline
−1 −1
problem, the instrument shall be purged with dry air or
betweenapproximately680cm and670cm )[64741-68-0].
nitrogen. A subsequent single beam spectrum shall be taken
8.1.10 Hexane (an absorbance versus water of less than 0.1
under the same conditions and ratioed to the background
at 250 nm usinga1cm cell) [110-54-3].
spectrum. The RMS noise of the ratioed spectra, the 100%
8.1.11 2,2,4-Trimethylpentane (isooctane) [540-84-1].
line, shall not exceed 0.3 % transmittance in the region from
8.1.12 Pentane (an absorbance versus water of less than 0.1
–1
700 to 664 cm .
at 250 nm usinga1cm cell) [109-66-0].
7.2 Absorption Cell— The absorption cell can be either
8.1.13 Propylbenzene [103-65-1].
transmission or attenuated total reflectance.
8.1.14 Toluene [108-88-3].
8.1.15 1,3,5-Trimethylbenzene (mesitylene) [108-67-8].
8.1.16 m-Xylene [108-38-3].
TABLE 1 Specification for Filters Used in Filter-based Mid-IR Test
NOTE 1—Only some of the reagents are required in each calibration or
Center Wavenumber Bandwidth (in wavelength units)
qualification procedure.
(± 0.15 % of wavenumber) (full width at half height)
-1
673 cm 1% of λ
c
-1
729 cm 1% of λ 9. Sampling and Sample Handling
c
-1
769 cm 1% of λ
c
-1
9.1 General Requirements:
1205 cm 1% of λ
c
-1
1054 cm 1% of λ
c
9.1.1 The sensitivity of the measurement of benzene to the
-1
1188 cm 1% of λ
c
-1 loss of benzene or other components through evaporation and
1117 cm 1% of λ
c
the resulting changes in composition is such that the utmost
D6277−07 (2012)
precaution and the most meticulous care in the drawing and 11.3 If correction of out-of-control behavior requires repair
handling of samples is required. to the instrument or recalibration of the instrument, the
9.1.2 Fuel samples to be analyzed by the test method shall qualificationofinstrumentperformancedescribedinA1.3shall
be sampled using procedures outlined in Practices D4057, be performed before the system is used to measure benzene
D4177,or D5842, where appropriate. Do not use the “Sam- content on samples.
pling by Water Displacement.” With some alcohol containing
samples, the alcohol will dissolve in the water phase.
12. Procedure
9.1.3 Protect samples from excessive temperatures prior to
12.1 Equilibratethesamplestobetween15and38°Cbefore
testing. This can be accomplished by storage in an appropriate
analysis.
ice bath or refrigerator at 0 to 5°C.
12.2 Clean the sample cell. If a separate baseline using the
9.1.4 Donottestsamplesstoredinleakycontainers.Discard
emptycellisrequired,andifresidualfuelisinthesamplecell,
and obtain a new sample if leaks are detected.
remove the fuel by flushing the cell and inlet-outlet lines with
9.2 Sample Handling During Analysis:
enough pentane to ensure complete washing. Evaporate the
9.2.1 When analyzing samples by the mid infrared
residual pentane with either dry air or nitrogen.
apparatus, the sample must be between a temperature of 15 to
38° C. Equilibrate all samples to the temperature of the
12.3 If needed, obtain a baseline spectrum in the manner
laboratory (15 to 38°C) prior to analysis by this test method. established by the manufacturer of the equipment.
9.2.2 After analysis, if the sample is to be saved, reseal the
12.4 Priortotheanalysisofunknowntestsamples,establish
container and store the sample in an ice bath or a refrigerator
that the equipment is running properly by collecting the
at 0 to 5°C.
spectrum of the quality control standard(s), by analyzing the
spectrum with the calibration model, and by comparing the
10. Calibration and Qualification of the Apparatus
estimatedbenzeneconcentrationtotheknownvaluefortheQC
10.1 Before use, the instrument must be calibrated accord-
standard(s).Introduceenoughstandardtothecelltoensurethat
ing to the procedure described in Annex A1. This calibration
the cell is washed a minimum of three times with the standard
can be performed by the instrument manufacturer prior to
solution.
deliveryoftheinstrumenttotheenduser.If,aftermaintenance,
12.5 Introduce the unknown fuel sample in the manner
the instrument calibration is repeated, the qualification proce-
established by the manufacturer. Introduce enough of the fuel
dure must also be repeated.
sample to the cell to ensure the cell is washed a minimum of
10.2 Before use, the instrument must be qualified according
three times with the fuel.
totheproceduredescribedinAnnexA1.Thequalificationneed
12.6 Obtain the spectral response of the fuel sample.
only be carried out when the instrument is initially put into
12.6.1 IfafilterbasedmidIRinstrumentisused,acquirethe
operation, recalibrated, or repaired.
absorbance for the fuel sample at the wavelengths correspond-
ing to the specified filters.
11. Quality Control Checks
12.6.2 IfanFTIRisused,acquirethedigitizedspectraldata
11.1 Confirm the calibration of the instrument each day it is
–1
for the fuel sample over the frequency region from 4000 cm
used by measuring the benzene concentration using the proce- –1
to 600 cm .
dure outlined in Section 12 on at least one quality control
12.7 Determine the benzene concentration (volume %) ac-
sample of known benzene content. The preparation of known
cording to the appropriate calibration equation developed in
benzene concentration is described in 11.1.1 and 11.1.2.
Annex A1.
11.1.1 Standard(s) of known benzene concentration shall be
made up by mass according to A1.1 and converted to volume 12.7.1 For filter based mid IR instruments, apply the cali-
bration equation determined in A1.2.4 to convert the absor-
% using the measured density as outlined in Section 13.At
least one standard shall be made up at 1.2 (6 0.2) mass % bancesateachofthewavelengthstothebenzeneconcentration
expressed in volume %.
benzene,thatis,nominally1.0volume%.Additionalstandards
may also be prepared and used for quality control checks.
12.7.2 For FTIR instruments using a PLS calibration, deter-
11.1.2 Standard(s) should be prepared in sufficient volume mine the benzene concentration using the calibration models
to allow for a minimum of 30 quality control measurements to
developedinA1.2.5byfollowingthestepsoutlinedasfollows.
be made on one batch of material. Package or store, or both,
12.7.2.1 Baseline correct the spectrum using a linear base-
–1
quality control samples to ensure that all analyses of quality
line fit to absorbances measured between 712 and 658 cm .
control samples from a given lot are performed on essentially
12.7.2.2 Estimate the benzene concentration in the fuel
identical material.
sample by applying the low calibration (see A1.2.5.1)tothe
–1
baseline corrected spectrum in the region of 712 to 664 cm .
11.2 If the benzene volume % value estimated for the
quality control sam
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.