ASTM D7861-14(2019)

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: D7861 − 14 (Reapproved 2019)
Standard Test Method for
Determination of Fatty Acid Methyl Esters (FAME) in Diesel
Fuel by Linear Variable Filter (LVF) Array Based Mid-Infrared
Spectroscopy
This standard is issued under the fixed designation D7861; 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 Gravity of Crude Petroleum and Liquid Petroleum Prod-
ucts by Hydrometer Method
1.1 This test method determines fatty acid methyl esters
D4052 Test Method for Density, Relative Density, and API
(FAME or biodiesel) in diesel fuel oils. FAME can be
Gravity of Liquids by Digital Density Meter
quantitatively determined from 1.0 % to 30.0 % by volume.
D4057 Practice for Manual Sampling of Petroleum and
This test method uses linear variable filter (LVF) array based
Petroleum Products
mid-infrared spectroscopy for monitoring FAME concentra-
D4177 Practice for Automatic Sampling of Petroleum and
tion.
Petroleum Products
NOTE 1—See Section 6 for a list of interferences that could affect the
D4307 Practice for Preparation of Liquid Blends for Use as
results produced from this method.
Analytical Standards
1.2 This test method uses a horizontal attenuated total
D5854 Practice for Mixing and Handling of Liquid Samples
reflectance (HATR) crystal and a univariate calibration.
of Petroleum and Petroleum Products
D6299 Practice for Applying Statistical Quality Assurance
1.3 The values stated in SI units are to be regarded as
and Control Charting Techniques to Evaluate Analytical
standard. No other units of measurement are included in this
Measurement System Performance
standard.
D6300 Practice for Determination of Precision and Bias
1.4 This standard does not purport to address all of the
Data for Use in Test Methods for Petroleum Products and
safety concerns, if any, associated with its use. It is the
Lubricants
responsibility of the user of this standard to establish appro-
D6751 Specification for Biodiesel Fuel Blend Stock (B100)
priate safety, health, and environmental practices and deter-
for Middle Distillate Fuels
mine the applicability of regulatory limitations prior to use.
D7371 Test Method for Determination of Biodiesel (Fatty
1.5 This international standard was developed in accor-
AcidMethylEsters)ContentinDieselFuelOilUsingMid
dance with internationally recognized principles on standard-
Infrared Spectroscopy (FTIR-ATR-PLS Method)
ization established in the Decision on Principles for the
D7467 Specification for Diesel Fuel Oil, Biodiesel Blend
Development of International Standards, Guides and Recom-
(B6 to B20)
mendations issued by the World Trade Organization Technical
E168 Practices for General Techniques of Infrared Quanti-
Barriers to Trade (TBT) Committee.
tative Analysis
E1655 Practices for Infrared Multivariate Quantitative
2. Referenced Documents
Analysis
2.1 ASTM Standards:
D975 Specification for Diesel Fuel Oils
3. Terminology
D1298 Test Method for Density, Relative Density, or API
3.1 Definitions:
3.1.1 biodiesel, n—fuel comprised of mono-alkyl esters of
This test method is under the jurisdiction of ASTM Committee D02 on
long chain fatty acids derived from vegetable oils or animal
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
fats, designated B100.
Subcommittee D02.04.0F on Absorption Spectroscopic Methods.
CurrenteditionapprovedMay1,2019.PublishedJuly2019.Originallyapproved
3.1.2 biodiesel blend (BXX), n—blend of biodiesel fuel with
ɛ1
in 2014. Last previous edition approved in 2014 as D7861 – 14 . DOI: 10.1520/
diesel fuel oils.
D7861-14R19.
3.1.2.1 Discussion—In the abbreviation, BXX, the XX rep-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
resents the volume percentage of biodiesel fuel in the blend.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 3.1.3 diesel fuel, n—petroleum-based middle distillate fuel.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7861 − 14 (2019)
3.1.4 univariate calibration, n—a process for creating a 6.4 Due to the inherent variability in LVFs, calibrations
calibration model in which a single measured variable, for cannot be transferred between instruments. Each instrument
example, the absorbance at a particular wavelength, is corre- shall be calibrated separately prior to use.
lated with the concentration or property values for a set of
6.5 This test method is not appropriate for fatty acid ethyl
calibration samples.
esters (FAEE). FAEEs will cause a negative bias.
3.2 Acronyms:
7. Apparatus
3.2.1 ATR, n—attenuated total reflectance
7.1 Mid-Infrared Spectrometer:
3.2.2 BXX, n—see 3.1.2
7.1.1 LVF Array Based Mid-Infrared Spectrometer—The
3.2.3 FAEE, n—fatty acid ethyl esters
type of apparatus suitable for use in this test method employs
3.2.4 FAME, n—fatty acid methyl esters an IR source, a HATR crystal, a LVF paired to a detector array,
an A/D converter, a microprocessor, and controller software.
3.2.5 HATR, n—horizontal attenuated total reflectance
Specifications of sub parts of the analyzer listed below will
3.2.6 LVF, n—linear variable filter
determinetheapplicabilityofaninstrumenttothistestmethod.
7.1.2 The noise level shall be established by acquiring a
4. Summary of Test Method
single beam spectrum of air.The single beam spectrum may be
4.1 A sample of diesel fuel or biodiesel blend (BXX) is an average of multiple instrument scans but the total collection
placed onto a HATR sample crystal. Infrared light is imaged time shall not exceed 60 s. The noise of the spectrum at 100 %
through the sample, then through the LVF and finally onto a transmission shall be less than 0.3 % in the range of 5.50 µm to
-1 -1
detector array. The LVF separates the infrared light into 5.90 µm (1818 cm to 1725 cm ).
specific wavelengths so that the response of the detector array
7.2 Detector Array/Linear Variable Filter Specifications—
generates an infrared spectrum. Spectral corrections are per-
The infrared detector array shall have at least 128 detection
formed to eliminate interferences caused by diesel and bio-
channels. This detector array shall be paired to a LVF with a
diesel variations. A wavelength region of the absorption
range that includes the region of 5.4 µm to 6.0 µm.At least ten
spectrum that correlates highly with biodiesel is selected for
detectorchannelsshallbewithintherangeof5.4 µmto6.0 µm.
analysis. The area of the selected region is determined. A -1
The filter shall have a resolution of at least 50 cm .
calibration curve converts the selected area of an unknown
7.3 Horizontal Attenuated Total Reflection Crystal—Ahori-
sample to a concentration of biodiesel.
zontal attenuated total reflectance (ATR) crystal, with zinc
4.2 This test method uses a LVF array based mid-infrared
selenide element mounted on a horizontal plate shall be used.
spectrometer with an HATR crystal. The absorption spectrum
Any number of internal reflections (bounces) may be used,
shall be used to calculate a calibration curve. -1
however the absorbance at 1745 cm shall not exceed 1.1
absorbance units for the highest concentration calibration
5. Significance and Use
standard used in the calibration range. Therefore, for higher
concentration measurements, careful consideration of element
5.1 Biodiesel is a fuel commodity primarily used as a
length and face angle shall be made to maximize sensitivity
blending component with diesel fuel. It is important to check
-1
without exceeding 1.1 absorbance units at 1745 cm .
the concentration of biodiesel in the diesel fuel in order to
make sure it is either not below the minimum allowable limit
7.4 Note that other spectrometer configurations can provide
and or does not exceed the maximum allowable limit.
adequate results; however, the precision and bias data listed
with this test method was collected based on these apparatus
5.2 This test method is applicable for quality control in the
specifications.Any modifications can result in precision and or
production and distribution of diesel fuel and biodiesel blends.
bias that differ from the numbers listed in this test method.
6. Interferences
8. Reagents and Materials
6.1 The hydrocarbon composition of diesel fuels can affect
8.1 Purity of Reagents—Spectroscopic grade (preferred) or
the accuracy of the calibration.When possible it is advised that
reagent grade chemicals shall be used in tests. Unless other-
diesel fuels used in calibration be similar to the unknown
wise indicated, it is intended that all reagents shall conform to
samples to be analyzed.
thespecificationsofthecommitteeonanalyticalreagentsofthe
6.2 Undissolved Water and Particulates—Samples contain- American Chemical Society, where such specifications are
available. Other grades may be used, provided it is first
ing undissolved water, particulates, or both will result in
erroneous results. If the sample is cloudy or water saturated ascertained that the reagent is of sufficiently high purity to
permit its use without lessening the accuracy of the determi-
after it has been equilibrated between 15 °C to 27 °C, filter the
sample through a qualitative filter paper until clear prior to nation.
their introduction onto the instrument sample crystal.
Reagent Chemicals, American Chemical Society Specifications, American
6.3 The primary spectral interferences are vegetable oils or
Chemical Society, Washington, D.C. For suggestions on the testing of reagents not
animal fats, or both. Other means of analysis or separate
listed by the American Chemical Society, see Annual Standards for Laboratory
calibrations may be required if fuel is suspected to be contami-
Chemicals,BDHLtd.,Poole,Dorset,U.K.,andtheUnitedStatesPharmacopeiaand
nated with vegetable oils or animal fats, or both. National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D7861 − 14 (2019)
8.1.1 Hexane, anhydrous [110-54-3] or Heptane [142-82-5] concentration of at least one quality control sample that is
for use as a cell cleaning agent. similar in composition and matrix to samples routinely ana-
8.1.2 B100 used for calibration, qualification, and quality lyzed. For details on quality control sample selection,
control standards are recommended to be compliant with preparation, testing, and control charting, refer to Practice
Specification D6751 or similar FAME specifications. The D6299.
biodiesel(B100)shallbeFAME.ABQ-9000certifiedproducer
11.3 A system that is found to be out of statistical control
for the biodiesel is recommended to ensure quality of product.
cannot be used until the root cause(s) of out-of-control is
8.1.3 Middle distillate fuel used for calibration,
identified and corrected.
qualification, and quality control standards are recommended
11.4 If correction of out-of-control behavior requires repair
to be compliant with Specification D975 or similar diesel fuel
to the instrument or recalibration of the instrument, the
specifications, be free of biodiesel or biodiesel oil precursor, or
qualificationofinstrumentperformancedescribedinA1.3shall
both. If possible, middle distillate fuel shall be representative
be performed and the in-statistical control status shall be
of diesel fuels anticipated for blends to be analyzed (crude
confirmed.
source, 1D, 2D, blends, winter/summer cuts, low aromatic
content, high aromatic content, and so forth).
12. Procedure
12.1 Equilibrate the samples to between 15 °C and 27 °C
9. Sampling, Test Specimens, and Test Units
before analysis.
9.1 General Requirements:
12.2 Clean the sample crystal of any residual fuel or other
9.1.1 Fuel samples to be analyzed by this test method shall
contamination according to the manufacturer’s recommenda-
be sampled using procedures outlined in Practice D4057 or
tion. Hexane or heptane has been determined to be suitable for
D4177, where appropriate. Do not use “sampling by water
cleaning the sample cell. It is recommended that the sample
displacement.” FAME is more water-soluble than the hydro-
crystal be cleaned at least twice before a baseline spectrum is
carbon base in a biodiesel blend.
obtained since a clean baseline spectrum is critical for ensuring
9.1.2 Protect samples from excessive temperatures prior to
correct results.
testing.
9.1.3 Donottestsamplesstoredinleakycontainers.Discard
12.3 Obtain a baseline spectrum in the manner established
and obtain a new sample if leaks are detected.
by the manufacturer of the equipment.
9.2 Sample Handling During Analysis:
12.4 Priortotheanalysisofunknowntestsamples,establish
9.2.1 When analyzing samples using this method, the
that the equipment is running properly by collecting the
sample temperature needs to be within the range of 15 °C to
spectrum of the quality control standard(s) and comparing the
27 °C.Equilibrateallsamplestothetemperatureofthetestsite
estimated biodiesel concentration(s) to the known value(s) for
(15 °C to 27 °C) prior to analysis by this test method.
the QC standard(s).
9.2.2 After the analysis, if the sample is to be retained,
12.5 Introduce the unknown fuel sample in the manner
reseal the container before storage.
established by the manufacturer. Ensure that the entire crystal
9.2.3 Avoid using plastic materials for sampling and do not
surface is covered with fuel.
use rubber caps or plastic bottles for storage of the sample.
12.6 Obtain the digitized spectral response of the fuel
10. Preparation of Apparatus
sample in the manner established by the manufacturer of the
equipment in a spectral range containing 5.4 µm to 6.0 µm.
10.1 Before use, the instrument needs to be calibrated
according to the procedure described i
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