ASTM D6277-07(2017)

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 30-Sep-2017
• ICS: 71.040.50 - Physicochemical methods of analysis
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0F - Absorption Spectroscopic Methods

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 2017)
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 D5769Test Method for Determination of Benzene,Toluene,
and Total Aromatics in Finished Gasolines by Gas
1.1 This test method covers the determination of the per-
Chromatography/Mass Spectrometry
centage of benzene in spark-ignition engine fuels. It is appli-
D5842Practice for Sampling and Handling of Fuels for
cable to concentrations from 0.1 to 5 volume %.
Volatility Measurement
1.2 The values stated in SI units are to be regarded as
D5854Practice for Mixing and Handling of Liquid Samples
standard. No other units of measurement are included in this
of Petroleum and Petroleum Products
standard.
E168Practices for General Techniques of Infrared Quanti-
1.3 This standard does not purport to address all of the
tative Analysis
safety concerns, if any, associated with its use. It is the E1655 Practices for Infrared Multivariate Quantitative
responsibility of the user of this standard to establish appro-
Analysis
priate safety, health, and environmental practices and deter- E2056Practice for Qualifying Spectrometers and Spectro-
mine the applicability of regulatory limitations prior to use.
photometers for Use in Multivariate Analyses, Calibrated
1.4 This international standard was developed in accor- Using Surrogate Mixtures
dance with internationally recognized principles on standard-
3. Terminology
ization established in the Decision on Principles for the
3.1 Definitions:
Development of International Standards, Guides and Recom-
3.1.1 multivariate calibration—a process for creating a
mendations issued by the World Trade Organization Technical
calibrationmodelinwhichmultivariatemathematicsisapplied
Barriers to Trade (TBT) Committee.
to correlate the absorbances measured for a set of calibration
2. Referenced Documents
samples to reference component concentrations or property
values for the set of samples.
2.1 ASTM Standards:
3.1.1.1 Discussion—The resultant multivariate calibration
D1298Test Method for Density, Relative Density, or API
modelisappliedtotheanalysisofspectraofunknownsamples
Gravity of Crude Petroleum and Liquid Petroleum Prod-
to provide an estimate of the component concentration or
ucts by Hydrometer Method
property values for the unknown sample.
D4052Test Method for Density, Relative Density, and API
3.1.1.2 Discussion—Included in the multivariate calibration
Gravity of Liquids by Digital Density Meter
algorithms are Partial Least Squares, Multilinear Regression,
D4057Practice for Manual Sampling of Petroleum and
and Classical Least Squares Peak Fitting.
Petroleum Products
D4177Practice for Automatic Sampling of Petroleum and 3.1.2 oxygenate—an oxygen-containing organic compound
which may be used as a fuel or fuel supplement, for example,
Petroleum Products
D4307Practice for Preparation of Liquid Blends for Use as various alcohols and ethers.
Analytical Standards
4. Summary of Test Method
4.1 Asampleofspark-ignitionenginefuelisintroducedinto
This test method is under the jurisdiction of ASTM Committee D02 on
aliquidsamplecell.Abeamofinfraredlightisimagedthrough
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
the sample onto a detector, and the detector response is
Subcommittee D02.04.0F on Absorption Spectroscopic Methods.
determined.Wavelengthsofthespectrum,thatcorrelatehighly
Current edition approved Oct. 1, 2017. Published November 2017. Originally
with benzene or interferences, are selected for analysis using
approved in 1998. Last previous edition approved in 2012 as D6277–07 (2012).
DOI: 10.1520/D6277-07R17.
selective bandpass filters or by mathematically selecting areas
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
of the whole spectrum. A multivariate mathematical analysis
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
converts the detector response for the selected areas of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. spectrum of an unknown to a concentration of benzene.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6277−07 (2017)
5. Significance and Use line, shall not exceed 0.3 % transmittance in the region from
–1 –1
700cm to 664 cm .
5.1 Benzene is a compound that endangers health, and the
concentration is limited by environmental protection agencies 7.2 Absorption Cell—The absorption cell can be either
to produce a less toxic gasoline. transmission or attenuated total reflectance.
7.2.1 Transmission Cells, shall have windows of potassium
5.2 This test method is fast, simple to run, and inexpensive.
bromide, zinc selenide, or other material having a significant
–1 –1
5.3 This test method is applicable for quality control in the
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 0.025mm 6 0.005mm. 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
integral to cell body
and proper utilization of multivariate calibration techniques
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
sample interface 53.8°
types):
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
−1
(1428 cm band of acetone) 0.38 AU ± 0.02 AU
employesanIRsource,aninfraredtransmissioncelloraliquid
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
8. Reagents and Materials (see Note 1)
microprocessor, and a method to introduce the sample. The
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 –1
scan range 4000 cm to 600 cm
8.1.5 1,3 Dimethylbenzene (m-xylene).
–1
resolution 4 cm
8.1.6 Ethanol [64-17-5].
–1
S/N at 674 cm >300:1 RMS
8.1.7 Ethylbenzene [100-41-4].
The signal to noise level will be established by taking a
8.1.8 3–Ethyltoluene [620-14-4].
singlebeamspectrumusingairornitrogenasthereferenceand
8.1.9 Heavy aromatic/reformate petroleum stream (high
declaring that spectrum as the background. The background
boilingcut:IPBof150 65°CandEPof245 68°C)certified
single beam spectrum obtained can be the average of multiple
to contain less than 0.025% benzene (an absorbance of less
FTIR scans, but the total collection time shall not exceed 60 s.
−1
than 0.03 at 675 cm using a 0.2 mm cell and a baseline
If interference from water vapor or carbon dioxide is a
−1 −1
betweenapproximately680cm and670cm )[64741-68-0].
problem, the instrument shall be purged with dry air or
8.1.10 Hexane (an absorbance versus water of less than 0.1
nitrogen. A subsequent single beam spectrum shall be taken
at 250 nm usinga1cm cell) [110-54-3].
under the same conditions and ratioed to the background
8.1.11 2,2,4-Trimethylpentane (isooctane) [540-84-1].
spectrum. The RMS noise of the ratioed spectra, the 100%
8.1.12 Pentane (an absorbance versus water of less than 0.1
at 250 nm usinga1cm cell) [109-66-0].
8.1.13 Propylbenzene [103-65-1].
TABLE 1 Specification for Filters Used in Filter-based Mid-IR Test
8.1.14 Toluene [108-88-3].
Center Wavenumber Bandwidth (in wavelength units)
(± 0.15 % of wavenumber) (full width at half height) 8.1.15 1,3,5-Trimethylbenzene (mesitylene) [108-67-8].
-1
673 cm 1% of λ 8.1.16 m-Xylene [108-38-3].
c
-1
729 cm 1% of λ
c
-1
NOTE 1—Only some of the reagents are required in each calibration or
769 cm 1% of λ
c
-1
1205 cm 1% of λ qualification procedure.
c
-1
1054 cm 1% of λ
c
-1
1188 cm 1% of λ
c
9. Sampling and Sample Handling
-1
1117 cm 1% of λ
c
9.1 General Requirements:
D6277−07 (2017)
9.1.1 The sensitivity of the measurement of benzene to the measurement system is out-of-control and cannot be used to
loss of benzene or other components through evaporation and estimate benzene concentrations until the cause of the out-of-
the resulting changes in composition is such that the utmost control behavior is identified and corrected.
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 Equilibrate the samples to between 15°C and 38°C
testing. This can be accomplished by storage in an appropriate
before analysis.
ice bath or refrigerator at 0°C to 5°C.
9.1.4 Donottestsamplesstoredinleakycontainers.Discard
12.2 Clean the sample cell. If a separate baseline using the
and obtain a new sample if leaks are detected.
emptycellisrequired,andifresidualfuelisinthesamplecell,
9.2 Sample Handling During Analysis: remove the fuel by flushing the cell and inlet-outlet lines with
enough pentane to ensure complete washing. Evaporate the
9.2.1 When analyzing samples by the mid infrared
apparatus, the sample must be between a temperature of 15°C residual pentane with either dry air or nitrogen.
to 38°C. Equilibrate all samples to the temperature of the
12.3 If needed, obtain a baseline spectrum in the manner
laboratory (15°C to 38°C) prior to analysis by this test
established by the manufacturer of the equipment.
method.
12.4 Priortotheanalysisofunknowntestsamples,establish
9.2.2 After analysis, if the sample is to be saved, reseal the
that the equipment is running properly by collecting the
container and store the sample in an ice bath or a refrigerator
spectrum of the quality control standard(s), by analyzing the
at 0°C to 5°C.
spectrum with the calibration model, and by comparing the
10. Calibration and Qualification of the Apparatus
estimatedbenzeneconcentrationtotheknownvaluefortheQC
standard(s).Introduceenoughstandardtothecelltoensurethat
10.1 Before use, the instrument must be calibrated accord-
the cell is washed a minimum of three times with the standard
ing to the procedure described in Annex A1. This calibration
solution.
can be performed by the instrument manufacturer prior to
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
sample of known benzene content. The preparation of known 12.7 Determine the benzene concentration (volume %) ac-
benzene concentration is described in 11.1.1 and 11.1.2. cording to the appropriate calibration equation developed in
11.1.1 Standard(s) of known benzene concentration shall be Annex A1.
made up by mass according to A1.1 and converted to volume
12.7.1 For filter based mid IR instruments, apply the cali-
% using the measured density as outlined in Section 13.At
bration equation determined in A1.2.4 to convert the absor-
least one standard shall be made up at 1.2 (6 0.2) mass %
bancesateachofthewavelengthstothebenzeneconcentration
benzene,thatis,nominally1.0volume%.Additionalstandards
expressed in volume %.
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 on
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6277 − 07 (Reapproved 2012) D6277 − 07 (Reapproved 2017)
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. 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
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by
Hydrometer Method
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards
D5769 Test Method for Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas
Chromatography/Mass Spectrometry
D5842 Practice for Sampling and Handling of Fuels for Volatility Measurement
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
E168 Practices for General Techniques of Infrared Quantitative Analysis
E1655 Practices for Infrared Multivariate Quantitative Analysis
E2056 Practice for Qualifying Spectrometers and Spectrophotometers for Use in Multivariate Analyses, Calibrated Using
Surrogate Mixtures
3. Terminology
3.1 Definitions:
3.1.1 multivariate calibration—a process for creating a calibration model in which multivariate mathematics is applied to
correlate the absorbances measured for a set of calibration samples to reference component concentrations or property values for
the set of samples.
3.1.1.1 Discussion—
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.04.0F on Absorption Spectroscopic Methods.
Current edition approved Nov. 1, 2012Oct. 1, 2017. Published November 2012November 2017. Originally approved in 1998. Last previous edition approved in 20072012
as D6277–07. –07 (2012). DOI: 10.1520/D6277-07R12.10.1520/D6277-07R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
D6277 − 07 (2017)
The resultant multivariate calibration model is applied to the analysis of spectra of unknown samples to provide an estimate of the
component concentration or property values for the unknown sample.
3.1.1.2 Discussion—
Included in the multivariate calibration algorithms are Partial Least Squares, Multilinear Regression, and Classical Least Squares
Peak Fitting.
3.1.2 oxygenate—an oxygen-containing organic compound which may be used as a fuel or fuel supplement, for example,
various alcohols and ethers.
4. Summary of Test Method
4.1 A sample of spark-ignition engine fuel is introduced into a liquid sample cell. A beam of infrared light is imaged through
the sample onto a detector, and the detector response is determined. Wavelengths of the spectrum, that correlate highly with
benzene or interferences, are selected for analysis using selective bandpass filters or by mathematically selecting areas of the whole
spectrum. A multivariate mathematical analysis converts the detector response for the selected areas of the spectrum of an unknown
to a concentration of benzene.
5. 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.
6. Interferences
6.1 The primary spectral interferences are toluene and other monosubstituted aromatics. In addition, oxygenates can interfere
with measurements made with filter apparatus. Proper choice of the apparatus, proper design of a calibration matrix, and proper
utilization of multivariate calibration techniques can minimize these interferences.
7. Apparatus
7.1 Mid-IR Spectrometric Analyzer (of one of the following types):
7.1.1 Filter-based Mid-IR Test Apparatus—The type of apparatus suitable for use in this test method minimally employes an
IR source, an infrared transmission cell or a liquid attenuated total internal reflection cell, wavelength discriminating filters, a
chopper wheel, a detector, an A-D converter, a microprocessor, and a method to introduce the sample. The frequencies and
bandwidths of the filters are specified in Table 1.
7.1.2 Fourier Transform Mid-IR Spectrometer—The type of apparatus suitable for use in this test method employs an IR source,
an infrared transmission cell or a liquid attenuated total internal reflection cell, a scanning interferometer, a detector, an A-D
converter, a microprocessor, and a method to introduce the sample. The following performance specifications (through the ATR
cell) must be met:
–1
scan range 4000 to 600 cm
–1 –1
scan range 4000 cm to 600 cm
–1
resolution 4 cm
–1
S/N at 674 cm >300:1 RMS
The signal to noise level will be established by taking a single beam spectrum using air or nitrogen as the reference and declaring
that spectrum as the background. The background single beam spectrum obtained can be the average of multiple FTIR scans, but
the total collection time shall not exceed 60 s. If interference from water vapor or carbon dioxide is a problem, the instrument shall
TABLE 1 Specification for Filters Used in Filter-based Mid-IR Test
Center Wavenumber Bandwidth (in wavelength units)
(± 0.15 % of wavenumber) (full width at half height)
-1
673 cm 1 % of λ
c
-1
729 cm 1 % of λ
c
-1
769 cm 1 % of λ
c
-1
1205 cm 1 % of λ
c
-1
1054 cm 1 % of λ
c
-1
1188 cm 1 % of λ
c
-1
1117 cm 1 % of λ
c
D6277 − 07 (2017)
be purged with dry air or nitrogen. A subsequent single beam spectrum shall be taken under the same conditions and ratioed to
the background spectrum. The RMS noise of the ratioed spectra, the 100 % line, shall not exceed 0.3 % transmittance in the region
–1 –1
from 700700 cm to 664 cm .
7.2 Absorption Cell—The absorption cell can be either transmission or attenuated total reflectance.
7.2.1 Transmission Cells, shall have windows of potassium bromide, zinc selenide, or other material having a significant
–1 –1
transmission from 712 cm to 660 cm . The cell path length of the transmission cell shall be 0.025 (6 0.005) mm. 0.025 mm
6 0.005 mm. The use of a wedged transmission cell with the same nominal path length is acceptable.
7.2.2 Attenuated Total Reflectance (ATR) Cells, shall have the following specifications:
ATR element material ZnSe
beam condensing optics conical, non-focussing optics
integral to cell body
element configuration circular cross section with
coaxial conical ends
cone half angle 60°
element length 1.55 in.
element diameter 0.125 in.
angle of incidence at
sample interface 53.8°
maximum range of
incidence angles ± 1.5°
standard absorbance
(1428 cm−1 band of acetone) 0.38 ± 0.02 AU
−1
(1428 cm band of acetone) 0.38 AU ± 0.02 AU
material of construction 316 stainless steel
seals Chemraz or Kalraz o-rings
8. Reagents and Materials (see Note 1)
8.1 Standards for Calibration, Qualification, and Quality Control Check Standards—Use of chemicals of at least 99 % purity,
where available, for quality control checks is required when preparing samples. (Warning—These materials are flammable and
may be harmful if ingested or inhaled.)
8.1.1 tert-Amyl methyl ether, TAME [994-05-8].
8.1.2 Benzene [1076-43-3].
8.1.3 tert-Butyl ethyl ether, ETBE [637-92-3].
8.1.4 tert-Butyl methyl ether, MTBE [1634-04-4].
8.1.5 1,3 Dimethylbenzene (m-xylene).
8.1.6 Ethanol [64-17-5].
8.1.7 Ethylbenzene [100-41-4].
8.1.8 3–Ethyltoluene [620-14-4].
8.1.9 Heavy aromatic/reformate petroleum stream (high boiling cut: IPB of 150 6 5° C and EP of 245 6 8° C) certified to
−1
contain less than 0.025 % benzene (an absorbance of less than 0.03 at 675 cm using a 0.2 mm cell and a baseline between
−1 −1
approximately 680 cm and 670 cm ) [64741-68-0].
8.1.10 Hexane (an absorbance versus water of less than 0.1 at 250 nm using a 1 cm cell) [110-54-3].
8.1.11 2,2,4-Trimethylpentane (isooctane) [540-84-1].
8.1.12 Pentane (an absorbance versus water of less than 0.1 at 250 nm using a 1 cm cell) [109-66-0].
8.1.13 Propylbenzene [103-65-1].
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].
NOTE 1—Only some of the reagents are required in each calibration or qualification procedure.
9. Sampling and Sample Handling
9.1 General Requirements:
9.1.1 The sensitivity of the measurement of benzene to the loss of benzene or other components through evaporation and the
resulting changes in composition is such that the utmost precaution and the most meticulous care in the drawing and handling of
samples is required.
9.1.2 Fuel samples to be analyzed by the test method shall be sampled using procedures outlined in Practices D4057, D4177,
or D5842, where appropriate. Do not use the “Sampling by Water Displacement.” With some alcohol containing samples, the
alcohol will dissolve in the water phase.
9.1.3 Protect samples from excessive temperatures prior to testing. This can be accomplished by storage in an appropriate ice
bath or refrigerator at 00 °C to 5°C.5 °C.
9.1.4 Do not test samples stored in leaky containers. Discard and obtain a new sample if leaks are detected.
D6277 − 07 (2017)
9.2 Sample Handling During Analysis:
9.2.1 When analyzing samples by the mid infrared apparatus, the sample must be between a temperature of 1515 °C to 38° C.
38 °C. Equilibrate all samples to the temperature of the laboratory (15(15 °C to 38°C)38 °C) prior to analysis by this test method.
9.2.2 After analysis, if the sample is to be saved, reseal the container and store the sample in an ice bath or a refrigerator at 00 °C
to 5°C.5 °C.
10. Calibration and Qualification of the Apparatus
10.1 Before use, the instrument must be calibrated according to the procedure described in Annex A1. This calibration can be
performed by the instrument manufacturer prior to delivery of the instrument to the end user. If, after maintenance, the instrument
calibration is repeated, the qualification procedure must also be repeated.
10.2 Before use, the instrument must be qualified according to the procedure described in Annex A1. The qualification need only
be carried out when the instrument is initially put into operation, recalibrated, or repaired.
11. Quality Control Checks
11.1 Confirm the calibration of the instrument each day it is used by measuring the benzene concentration using the procedure
outlined in Section 12 on at least one quality control sample of known benzene content. The preparation of known benzene
concentration is described in 11.1.1 and 11.1.2.
11.1.1 Standard(s) of known benzene concentration shall be made up by mass according to A1.1 and converted to volume %
using the measured density as outlined in Section 13. At least one standard shall be made up at 1.2 (6 0.2) mass % benzene, that
is, nominally 1.0 volume %. Additional standards may also be prepared and used for quality control checks.
11.1.2 Standard(s) should be prepared in sufficient volume to allow for a minimum of 30 quality control measurements to be
made on one batch of material. Package or store, or both, quality control samples to ensure that all analyses of quality control
samples from a given lot are performed on essentially identical material.
11.2 If the benzene volume % value estimated for the quality control sample prepared at 1.2 mass % benzene differs from the
known value by more than 0.12 volume %, then the measurement system is out-of-control and cannot be used to estimate benzene
concentrations until the cause of the out-of-control behavior is identified and corrected.
11.3 If correction of out-of-control behavior requires repair to the instrument or recalibration of the instrument, the qualification
of instrument performance described in A1.3 shall be performed before the system is used to measure benzene content on samples.
12. Procedure
12.1 Equilibrate the samples to between 1515 °C and 38°C38 °C before analysis.
12.2 Clean the sample cell. If a separate baseline using the empty cell is required, and if residual fuel is in the sample cell,
remove the fuel by flushing the cell and inlet-outlet lines with enough pentane to ensure complete washing. Evaporate the residual
pentane with either dry air or nitrogen.
12.3 If needed, obtain a baseline spectrum in the manner established by the manufacturer of the equipment.
12.4 Prior to the analysis of unknown test samples, establish that the equipment is running properly by collecting the spectrum
of the quality control standard(s), by analyzing the spectrum with the calibration model, and by comparing the estimated benzene
concentration to the known value for the QC sta
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