ASTM D6277-07(2022)

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 % by 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: Published
• Publication Date: 30-Apr-2022
• 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

Relations

• Refers: ASTM D5842-23 - Standard Practice for Sampling and Handling of Fuels for Volatility Measurement
• Effective Date: 01-Oct-2023
• Refers: ASTM D5842-19 - Standard Practice for Sampling and Handling of Fuels for Volatility Measurement
• Effective Date: 01-Nov-2019
• Refers: ASTM E2056-04(2016) - Standard Practice for Qualifying Spectrometers and Spectrophotometers for Use in Multivariate Analyses, Calibrated Using Surrogate Mixtures
• Effective Date: 01-Apr-2016
• Refers: ASTM D4307-99(2015) - Standard Practice for Preparation of Liquid Blends for Use as Analytical Standards
• Effective Date: 01-Oct-2015
• Refers: ASTM D5769-10(2015) - Standard Test Method for Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry
• Effective Date: 01-Jun-2015
• Refers: ASTM D5842-14 - Standard Practice for Sampling and Handling of Fuels for Volatility Measurement
• Effective Date: 15-Jan-2014
• Refers: ASTM D1298-12a - Standard Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
• Effective Date: 15-May-2012
• Refers: ASTM D1298-12 - Standard Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
• Effective Date: 01-Apr-2012
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D5769-10 - Standard Test Method for Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry
• Effective Date: 01-May-2010
• Refers: ASTM D5854-96(2010) - Standard Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
• Effective Date: 01-May-2010
• Refers: ASTM D4307-99(2010) - Standard Practice for Preparation of Liquid Blends for Use as Analytical Standards
• Effective Date: 01-May-2010
• Refers: ASTM E2056-04(2010) - Standard Practice for Qualifying Spectrometers and Spectrophotometers for Use in Multivariate Analyses, Calibrated Using Surrogate Mixtures
• Effective Date: 01-Mar-2010
• Refers: ASTM D5842-04(2009) - Standard Practice for Sampling and Handling of Fuels for Volatility Measurement
• Effective Date: 01-Jul-2009
• Refers: ASTM E168-06 - Standard Practices for General Techniques of Infrared Quantitative Analysis (Withdrawn 2015)
• Effective Date: 01-Mar-2006

Overview

ASTM D6277-07(2022), issued by ASTM International, specifies the standard test method for determining the percentage of benzene in spark-ignition engine fuels using mid infrared (mid-IR) spectroscopy. Benzene is known for its health risks, and environmental regulations worldwide restrict its concentration in gasoline. This ASTM standard provides a rapid, simple, and cost-effective method for benzene quantification, supporting quality control in fuel production and distribution. The method is applicable for benzene concentrations ranging from 0.1% to 5% by volume and is recognized internationally for harmonized trade practices and fuel safety compliance.

Key Topics

• Health and Environmental Significance: Benzene is a hazardous compound. Accurate measurement is essential to ensure compliance with regulatory limits and to reduce toxicity in gasoline.
• Mid Infrared (Mid-IR) Spectroscopy: Utilizes mid-IR spectrometric analyzers, either filter-based or Fourier Transform Infrared (FTIR) systems, for precise measurement of benzene.
• Calibration and Quality Control: Calibration and qualification of the instrument are mandatory. Regular quality control checks ensure ongoing accuracy and reliability.
• Sample Handling: Stringent sample collection and preservation practices must be followed to prevent loss or contamination, as benzene can volatilize easily.
• Precision and Repeatability: The method provides reproducible results across laboratories and operators, supporting regulatory compliance and product quality.
• Safety and Regulatory Compliance: Users must implement appropriate safety and environmental practices when performing benzene analysis.

Applications

This standard test method is primarily used in:

• Fuel Quality Control: Enables refineries and fuel distributors to monitor and control benzene content in spark-ignition engine fuels (such as gasoline) efficiently.
• Regulatory Compliance: Meets requirements set by environmental agencies for limiting benzene concentrations in commercial fuels.
• Production and Distribution Monitoring: Allows ongoing verification of benzene levels during the production and supply chain, reducing risks of non-compliance or batch contamination.
• Laboratory Testing: Suitable for routine laboratory analysis using mid-IR spectroscopy, including both filter-based and FTIR instrument configurations.
• International Trade: Assists in standardizing benzene measurement for traded fuels, supporting the reduction of technical barriers to trade as outlined by the World Trade Organization (WTO).

Related Standards

For comprehensive fuel analysis and sample handling, consider utilizing the following related ASTM standards:

• ASTM D5769: Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry.
• ASTM D4052 & D1298: Methods for determining the density and API gravity of petroleum products.
• ASTM D4057, D4177, and D5842: Guidelines for manual and automatic fuel sampling and handling.
• ASTM E168, E1655, and E2056: Practices for infrared quantitative analysis, multivariate calibration, and qualification of spectrometric instruments.

These standards work in conjunction to ensure safe, accurate, and repeatable fuel analysis, helping industries meet safety, environmental, and trade regulations.

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Keywords: ASTM D6277, benzene in gasoline, mid infrared spectroscopy, spark-ignition engine fuels, fuel quality control, regulatory compliance, fuel testing, FTIR, filter-based mid-IR, environmental standards, benzene analysis.

Standards Content (Sample)

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.
Designation:D6277 −07 (Reapproved 2022)
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% by 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, n—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, n—an oxygen-containing organic com-
pound which may be used as a fuel or fuel supplement, for
Petroleum Products
D4307Practice for Preparation of Liquid Blends for Use as example, 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 May 1, 2022. Published May 2022. Originally
with benzene or interferences, are selected for analysis using
approved in 1998. Last previous edition approved in 2017 as D6277–07 (2017).
DOI: 10.1520/D6277-07R22.
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 (2022)
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
boiling cut: IPB of 150°C 6 5°C and EP of 245°C 6 8°C)
single beam spectrum obtained can be the average of multiple
certified to contain less than 0.025% benzene (an absorbance
FTIR scans, but the total collection time shall not exceed 60 s.
−1
oflessthan0.03at675cm usinga0.2mmcellandabaseline
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 (2022)
9.1.1 The sensitivity of the measurement of benzene to the differs from the known value by more than 0.12% by volume,
loss of benzene or other components through evaporation and then the measurement system is out-of-control and cannot be
the resulting changes in composition is such that the utmost used to estimate benzene concentrations until the cause of the
precaution and the most meticulous care in the drawing and out-of-control behavior is identified and corrected.
handling of samples is required.
11.3 If correction of out-of-control behavior requires repair
9.1.2 Fuel samples to be analyzed by the test method shall
to the instrument or recalibration of the instrument, the
be sampled using procedures outlined in Practices D4057,
qualificationofinstrumentperformancedescribedinA1.3shall
D4177,or D5842, where appropriate. Do not use the “Sam-
be performed before the system is used to measure benzene
pling by Water Displacement.” With some alcohol containing
content on samples.
samples, the alcohol will dissolve in the water phase.
9.1.3 Protect samples from excessive temperatures prior to
12. Procedure
testing. This can be accomplished by storage in an appropriate
12.1 Equilibrate the samples to between 15°C and 38°C
ice bath or refrigerator at 0°C to 5°C.
before analysis.
9.1.4 Donottestsamplesstoredinleakycontainers.Discard
and obtain a new sample if leaks are detected.
12.2 Clean the sample cell. If a separate baseline using the
emptycellisrequired,andifresidualfuelisinthesamplecell,
9.2 Sample Handling During Analysis:
remove the fuel by flushing the cell and inlet-outlet lines with
9.2.1 When analyzing samples by the mid infrared
enough pentane to ensure complete washing. Evaporate the
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
laboratory (15°C to 38°C) prior to analysis by this test
12.3 If needed, obtain a baseline spectrum in the manner
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°C 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-
11. Quality Control Checks
ing to the specified filters.
11.1 Confirm the calibration of the instrument each day it is 12.6.2 IfanFTIRisused,acquirethedigitizedspectraldata
–1
for the fuel sample over the frequency region from 4000 cm
used by measuring the benzene concentration using the proce-
–1
dure outlined in Section 12 on at least one quality control to 600 cm .
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% by mass
bancesateachofthewavelengthstothebenzeneconcentration
benzene, that is, nominally 1.0% by volume. Additional
expressed in volume %.
standards may also be prepared and used for quality control
12.7.2 For FTIR instruments using a PLS calibration, deter-
checks.
mine the benzene concentration using the calibration models
11.1.2 Standard(s) should be prepared in sufficient volume
developedinA1.2.5byfollowingthestepsoutlinedasfollows.
to allow for a minimum of 30 quality control measurements to
12.7.2.1 Baseline correct the spectrum using a linear base-
–1
be made on one batch of material. Package or store, or both,
line fit to absorbances measured between 712cm and
quality control samples to ensure that all analyses of quality –1
658cm .
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
11.2 If the benzene volume % value estimated for the baseline corrected spectrum in the region of 712cm to
–1
quality control sample prepared at 1.2% by mass benzene 664cm .
D6277−07 (2022)
12.7.2.3 Iftheestimatedbenzeneconcentration(determined 14.1.2 FTIRinstrumentswithPLScalibration(TestMethod
in 12.7.2.2) is equal to or less than 1.30% by volume, D6277b).
determine the benzene concentration by applying the low 14.1.2.1 Volume % benzene byTest Method D6277b, to the
calibration(seeA1.2.5.2)tothebaselinecorrectedspectrumin nearest 0.01%.
–1 –1
the region of 712cm to 664 cm . 14.1.3 FTIRinstrumentswithCLScalibration(TestMethod
12.7.2.4 Iftheestimatedbenzeneconcentration(determined D6277c).
in 12.7.2.2) is greater than 1.30% by volume, estimate the 14.1.3.1 Volume % benzene byTest Method D6277c, to the
benzene concentration by applying the high calibration (see nearest 0.1%.
A1.2.5.3) to the baseline corrected spectrum in the region of
–1 –1
15. Precision and Bias
712cm to 664 cm .
12.7.2.5 If the value estimated by application of the high
15.1 Interlaboratory tests of each of the procedures (filter
calibration (determined in 12.7.2.4) is less than or equal to instruments, FTIR instruments with PLS calibration, and FTIR
1.30% by volume, report the value determined by the low
instruments with CLS calibration) were carried out using
calibration (even if the value is greater than 1.30% by twenty samples that covered the range from 0% to 1.8% by
volume). For estimated values greater than 1.30% by volume
volume and at least six laboratories for each of the procedures.
(determined in 12.7.2.4), report the value obtained.
Anadditionalsamplecontainingapproximately4%byvolume
12.7.3 For FTIR instruments using a classical least squares
benzene was also included in the interlaboratory results. The
peak fitting calibration, fit the absorption spectrum in the
precision of the test method as obtained by statistical exami-
–1 –1 3
region of 710cm through 660 cm using a classical least
nation of interlaboratory results is summarized in Table 2 and
squares fit (k-matrix method). The fit matrix must include the
Table 3 and is as follows:
derived spectra of toluene, 1,3-dimethylbenzene,
15.2 Repeatability for Filter Based Mid IR Instruments—
3-ethyltoluene, 1,3,5–trimethylbenzene, ethylbenzene, and
For benzene concentrations between 0.1% and 1.8% by
propylbenzene (as determined in A1.2.6.1).
volume,thedifferencebetweensuccessivetestresultsobtained
12.7.3.1 To eliminate spectral overlaps, subtract the derived
by the same operator with the same apparatus under constant
spectra of toluene, 1,3-dimethylbenzene, 3-ethyltoluene, 1,3,5-
operating conditions on identical test samples would, in the
trimethylbenzene, ethylbenzene and propylbenzene, multiplied
long run, and in the normal and correct operation of the test
by the coefficients that resulted from the classical least squares
method, exceed the following values only in one case in
fit to the absorption spectrum. In this way, a residual benzene
twenty:
peak is obtained.
r 50.02110.027 X (2)
12.7.3.2 Fit the residual benzene peak with a Lorentzian
line shape function (as defined in A1.2.6.4) with a linear
where X is the benzene concentration determined. For the
–1 –1
background in the region of 691cm through 660 cm and
one sample at approximately 4% by volume benzene, the
determine the peak height of the residual benzene peak.
difference between successive test results, obtained by the
12.7.3.3 Determine the benzene concentration expressed in
same operator with the same apparatus under constant operat-
mass % in the fuel sample by applying the calibration (see
ing conditions on identical test samples would, in the long run,
A1.2.6) using the peak height of the residual benzene peak
and in the normal and correct operation of the test method,
determined in 12.7.3.2.
exceed 0.18 only in one case in twenty.
12.7.3.4 Determine the density of the fuel sample by Test
15.3 Repeatability for FTIR Instruments Using PLS Cali-
Method D1298 or Test Method D4052.
bration Instruments—For benzene concentrations between
12.7.3.5 Convert the determined mass % to volume % for
0.1% and 1.8% by volume, the difference between successive
the sample using the equation in Section 13.
test results obtained by the same operator with the same
13. Calculation
13.1 Conversion to Volume % of Benzene—To convert the 3
Supporting data have been filed atASTM International Headquarters and may
calibration and qualification standards to volume % use Eq 1. beobtainedbyrequestingResearchReportRR:D02-1431.ContactASTMCustomer
Service at [e-mail].
V 5 M ~D /0.8844! (1)
b b f
TABLE 2 Repeatabilities as a Function of Concentration
where:
Benzene
V = benzene volume %,
b FTIR with PLS FTIR with CLS
Concentration Filter Instruments
M = benzene mass %, and
Calibration Calibration
b
(volume %)
D = relative density at 15.56°C of the calibration or
f
0.1 0.02 0.02 0.05
qualification standard being tested as determined by
0.3 0.03 0.03 0.06
0.5 0.03 0.04 0.07
Practice D1298 or Test Method D4052.
0.7 0.04 0.05 0.08
0.9 0.05 0.06 0.09
14. Report
1.1 0.05 0.07 0.09
14.1 Report the following information: 1.3 0.06 0.08 0.10
1.5 0.06 0.09 0.11
14.1.1 Filter instruments (Test Method D6277a).
1.8 0.07 0.11 0.12
14.1.1.1 Volume % benzene byTest Method D6277a, to the
4 0.18 0.14 0.18
nearest 0.01%.
D6277−07 (2022)
TABLE 3 Reproducibilites as a Function of Concentration
normal and correct operation of the test method, exceed 0.59
Benzene only in one case in twenty.
FTIR with PLS FTIR with CLS
Concentration Filter Instruments
Calibration Calibration
15.6 Reproducibility for FTIR Instruments Using a PLS
(volume %)
Calibration Instrument—For benzene concentrations between
0.1 0.12 0.03 0.10
0.3 0.12 0.06 0.11
0.1% and 1.8% by volume, the difference between two single
0.5 0.13 0.08 0.11
and independent results obtained by different operators work-
0.7 0.13 0.10 0.12
ing in different laboratories on identical test samples would, in
0.9 0.13 0.13 0.13
1.1 0.13 0.15 0.13
thelongrun,andinthenormalandcorrectoperationofthetest
1.3 0.14 0.18 0.14
method, exceed the following values only in one case in
1.5 0.14. 0.20 0.15
twenty:
1.8 0.14. 0.23 0.15
4 0.59 0.47 0.23
R 50.02210.118 X (6)
where X is the benzene concentration determined. For the
one sample at approximately 4% by volume benzene, the
differencebetweentwosingleandindependentresultsobtained
apparatus under constant operating conditions on identical test
by different operators working in different laboratories on
samples would, in the long run, and in the normal and cor
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