ASTM D6756-02
(Test Method)Standard Test Method for Determination of the Red Dye Concentration and Estimation of the ASTM Color of Diesel Fuel and Heating Oil Using a Portable Visible Spectrophotometer
Standard Test Method for Determination of the Red Dye Concentration and Estimation of the ASTM Color of Diesel Fuel and Heating Oil Using a Portable Visible Spectrophotometer
SIGNIFICANCE AND USE
In the United States, high sulfur content (defined by the United States Environmental Protection Agency (USEPA)) middle distillate products and diesel fuel used for off-road purposes, other than aviation turbine fuel, are required by government agencies to contain red dye. The dye concentration required to be present in high sulfur and off-road diesel products is regulated by the United States Environmental Protection Agency and the United States Internal Revenue Service, respectively.
Some fuels that are readily exchanged in the market have a color specification. The color of the base fuel is masked by the presence of the red dye. This test method provides a means of estimating the base color of Number 1 and Number 2 diesel fuel and heating oil in the presence of red dye.
The test method provides a means to indicate conformance to contractual and legal requirements.
SCOPE
1.1 This test method describes the determination of the red dye concentration of diesel fuel and heating oil and the estimation of the ASTM color of undyed and red-dyed diesel fuel and heating oil. The test method is appropriate for use with diesel fuel and heating oil of Grades 1 and 2 described in Specifications D 396, D 975, D 2880 and D 3699. Red dye concentrations are determined at levels equivalent to 0.1 to 20 mg/L of Solvent Red 26 in samples with ASTM colors ranging from 0.5 to 5. The ASTM color of the base fuel of red-dyed samples with concentration levels equivalent to 0.1 to 20 mg/L of Solvent Red 26 is estimated for the ASTM color range from 0.5 to 5. The ASTM color of undyed samples is estimated over the ASTM color range of 0.5 to 5.
1.2 The values stated in SI units are to be regarded as the 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.
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An American National Standard
Designation:D6756–02
Standard Test Method for
Determination of the Red Dye Concentration and Estimation
of the ASTM Color of Diesel Fuel and Heating Oil Using a
Portable Visible Spectrophotometer
This standard is issued under the fixed designation D6756; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Petroleum Products
D6045 TestMethodforColorofPetroleumProductsbythe
1.1 This test method describes the determination of the red
Automatic Tristimulus Method
dye concentration of diesel fuel and heating oil and the
E203 TestMethodforWaterUsingVolumetricKarlFischer
estimation of the ASTM color of undyed and red-dyed diesel
Titration
fuelandheatingoil.Thetestmethodisappropriateforusewith
E1655 Practices for Infrared, Multivariate, Quantitative
diesel fuel and heating oil of Grades 1 and 2 described in
Analysis
Specifications D396, D975, D2880 and D3699. Red dye
E2056 Practice for Qualifying Spectrometers and Spectro-
concentrations are determined at levels equivalent to 0.1 to 20
photometers for Use in Multivariate Analysis, Calibrated
mg/LofSolventRed26insampleswithASTMcolorsranging
Using Surrogate Mixtures
from 0.5 to 5. The ASTM color of the base fuel of red-dyed
sampleswithconcentrationlevelsequivalentto0.1to20mg/L
3. Terminology
ofSolventRed26isestimatedfortheASTMcolorrangefrom
3.1 Definitions:
0.5to5.TheASTMcolorofundyedsamplesisestimatedover
3.1.1 ASTM color, n—anempiricaldefinitionofthecolorof
the ASTM color range of 0.5 to 5.
a petroleum liquid based on a scale of 0.5 to 8 as determined
1.2 The values stated in SI units are to be regarded as the
by Test Method D1500.
standard.
3.1.2 surrogate calibration, n—a multivariate calibration
1.3 This standard does not purport to address all of the
that is developed using a calibration set which consists of
safety concerns, if any, associated with its use. It is the
mixtureswithpre-specifiedandreproduciblecompositionsthat
responsibility of the user of this standard to establish appro-
contain substantially fewer chemical components than the
priate safety and health practices and determine the applica-
samples which will ultimately be analyzed. E 2056
bility of regulatory limitations prior to use.
3.1.3 surrogate method, n—a standard test method that is
2. Referenced Documents based on a surrogate calibration. E 2056
3.2 Definitions of Terms Specific to This Standard:
2.1 ASTM Standards:
3.2.1 red dye, n—substance that, when added to fuel,
D396 Specification for Fuel Oils
2 absorbs green light and imparts a red color to the product. For
D975 Specification for Diesel Fuel Oils
this test method, red dyes are:
D1500 Test Method for ASTM Color of Petroleum Prod-
2 3.2.1.1 product dyes, n—alkyl derivatives of azobenzene-4-
ucts (ASTM Color Scale)
azo-2-naphthol (methyl derivatives of Color Index No. 26105)
D2880 Specification for Gas Turbine Fuel Oils
3 which are more soluble in diesel fuel.
D3699 Specification for Kerosine
3.2.1.2 solvent red 26, n—an azobenzene-4-azo-2-naphthol
D4052 Test Method for Density and Relative Density of
dye of a specific chemical structure that is used to gage the
Liquids by Digital Density Meter
amount of red dye present in a given sample.
D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
4. Summary of Test Method
D4177 Practice for Automatic Sampling of Petroleum and
4.1 A sample is introduced into the liquid specimen cell.
The cell is placed into the light path of the apparatus.Abeam
of visible light is imaged through the sample onto a detector,
This test method is under the jurisdiction of ASTM Committee D02 on
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Materials.
Current edition approved Feb. 10, 2002. Published April 2002. Annual Book of ASTM Standards, Vol 05.04.
2 5
Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 15.05.
3 6
Annual Book of ASTM Standards, Vol 05.02. Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6756–02
and the detector response is determined. Wavelengths of the 8.2 Precautions must be taken to shield the samples from
spectrum, which correlate highly with the red dye concentra- light prior to analysis.
tion and the ASTM color, are selected for analysis using
9. Calibration and Standardization of the Apparatus
selective bandpass filters. A multivariate mathematical model
converts the absorption values from the filters to the red dye 9.1 The instrument is calibrated according to the procedure
described in Annex A2.
concentration and the estimated ASTM color.
NOTE 1—The DT100C instruments are calibrated at the factory by the
5. Significance and Use
vendor.
5.1 In the United States, high sulfur content (defined by the
9.2 The instrument is qualified according to the procedure
United States Environmental Protection Agency (USEPA))
described in Annex A3.
middle distillate products and diesel fuel used for off-road
purposes, other than aviation turbine fuel, are required by
NOTE 2—The DT100C instruments are qualified at the factory by the
governmentagenciestocontainreddye.Thedyeconcentration
vendor.
required to be present in high sulfur and off-road diesel
9.2.1 If the qualification procedure is performed by the
products is regulated by the United States Environmental
vendor, then the user shall perform a quality control check
Protection Agency and the United States Internal Revenue
according to the procedure described in Section 10.
Service, respectively.
5.2 Some fuels that are readily exchanged in the market 10. Quality Control Check
haveacolorspecification.Thecolorofthebasefuelismasked
10.1 Toconfirmtheperformanceoftheinstrument,periodi-
by the presence of the red dye. This test method provides a
callymeasurethereddyeconcentrationandtheASTMcolorof
means of estimating the base color of Number 1 and Number
three control samples using the procedure outlined in Section
2 diesel fuel and heating oil in the presence of red dye.
11. The quality control check standards should be analyzed at
5.3 The test method provides a means to indicate conform-
least once a week or before the sample analysis if the
ance to contractual and legal requirements.
instrument is used less frequently than weekly or if the
instrument is moved to a different laboratory or field location.
6. Interferences
NOTE 3—Quality control samples are available from DT100C .
6.1 The presence of colorants other than the hydrocarbons
typical of Number 1 and 2 diesel fuel and heating oils, or the
10.1.1 A standard of known dye concentration and ASTM
presenceofreddyeotherthanthespecifiedtypes,caninterfere
color is made according to the information inA1.4. The set of
with the accurate determination of the red dye concentration
qualitycontrolsamplesshallhavealow,medium,andhighred
reported as Solvent Red 26 equivalent or the base fuelASTM
dye concentration (0 to 14 6 2 mg/L) and a low, medium, and
color.
high ASTM color (0 to 5 ASTM color units).
10.1.2 The standards are stable for at least one year when
7. Apparatus
stored in the dark in tightly sealed bottles.
7.1 Filter Spectrophotometer, is equipped with specimen
10.2 If the red dye concentration determined for one of the
chamber, visible wavelength source, four 10 6 2 nm (full
quality control samples differs from the known value by more
width at half transmission maximum) bandpass wavelength
than 1.0 mg/L or if the estimated ASTM color for one of the
discriminating filters having center wavelengths at 450 6 2
quality control samples differs from the known value by more
nm,520 62nm,650 62nm,and700 62nm.Thebandpass
than 0.5 units, then the measurement system is out-of-control
filters are used in conjunction with the visible wavelength
and cannot be used to determine the red dye concentration or
source to produce light in the blue, green, red, and far-red
used to estimate the ASTM color until the cause of the
regions of the electromagnetic spectrum. A detector converts
out-of-control behavior is corrected.
thetransmittedlighttoanelectronicsignalthatisprocessedby
10.3 If correction of out-of-control behavior requires repair
7,8
an A-D converter and a microprocessor.
to the instrument or recalibration of the instrument, the
7.2 Specimen Cell, constructed of polymethacrylate or clear
qualificationofinstrumentperformancedescribedinAnnexA3
optical glass having a path length of approximately 1 cm. If
shall be performed before the system is used to measure red
more than one cell is used for calibration, qualification and
dye concentration or used to estimate ASTM color.
sample measurement, the path length of the cells must be
matched to 60.001 cm. 11. Procedure
11.1 Prepare the filter spectrophotometer for operation in
8. Sampling
accordance with the manufacturer’s instructions.
8.1 Samples shall be taken in accordance with Practice
11.2 Equilibrate the sample to between 20 and 25°C.
D4057 or D4177.
11.3 Fill a clean, dry specimen cell. The external optical
surfaces must be clean. If not, wipe clean and dry with a piece
of lint-free paper (for example, lens paper).
DT100C instruments used to develop this precision statement are available
from PetroSpec, Inc., 530 Main St., Acton, MA 01720.
11.4 Insert the specimen cell into the cell chamber of the
Thesolesourceofsupplyoftheapparatusknowntothecommitteeatthistime
instrument.
isprovided.Ifyouareawareofalternativesuppliers,pleaseprovidethisinformation
11.5 Record the Solvent Red 26 equivalent concentration
to ASTM International Headquarters. Your comments will receive careful consid-
erationatameetingoftheresponsibletechnicalcommittee, whichyoumayattend. and the estimated ASTM color.
D6756–02
12. Report operation of the test method, exceed the following value in
only one case in twenty:
12.1 Report the red dye concentration to the nearest 0.1
mg/L as Solvent Red 26 equivalent dye. R 50.86mg/L
for Solvent Red 26 equivalent dye concentrations between
NOTE 4—The number of milligrams per litre of Solvent Red 26
equivalents measured by the DT100C instrument is labeled as ppm on the 0.1 and 20.0 mg/L, and
display.TheppmunitreportedbytheDT100Cinstrumentisequivalentto
R 50.20ASTMcolorunits
mg/L.
for samples in the ASTM color range of 0 to 5.
12.2 Report the estimated ASTM color value as: estimated
13.2 Bias—Since there is no accepted reference material
ASTM color using ASTM D 6756. Report the result to the
suitable for determining the bias for the procedure in this test
nearest 0.1 color value.
method, bias has not been determined.
12.2.1 The reported estimated ASTM color value can be
13.3 Relative Bias (Dye Concentration)—Some relative
converted to a value that mimics the reporting convention of
bias, among certain samples, was observed when the Solvent
the Test Method D1500. For estimated ASTM color values
Red 26 concentration results were compared to the expected
that are x.0 or x.5, the estimated value is reported unchanged.
Solvent Red 26 concentrations. The bias between the theoreti-
For estimated color values between x.1 and x.4, round up the
cal and measured Solvent Red 26 concentration is observed
value to the nearest x.5 and place an L before the result. For
with the test samples that were made using Solvent Red 164,
estimatedcolorvaluesbetweenx.6andx.9,roundupthevalue
the chemical used to commercially dye diesel fuel. The
to the nearest whole number and place an L before the result.
observed bias does appear to be of a systematic nature and is
If the estimated color value is greater than 8.0, report the
not known to be related to the accuracy of this test method,
estimated result as >8.
since the Solvent Red 26 equivalency of the Solvent Red 164
used in sample preparation has not been determined, only
13. Precision and Bias
estimated.
13.1 Interlaboratory tests of the procedure were carried out
13.4 Relative Bias (ASTM Color)—Relative bias, for one
usingsixteensamplescoveringthereddyeconcentrationrange
sample,wasobservedwhenthecolorresultswerecomparedto
equivalent to 0 to 16 mg/L of Solvent Red 26 equivalents and
the Test Method D1500 results; however, this bias is near the
covering the range of ASTM color from 0.5 to 3.0. Seven
reproducibility of the test methods and is inconclusive. The
laboratories participated in the interlaboratory tests. The pre-
overall relative bias to Test Method D1500 is not significant.
cision of this procedure as determined by the statistical
examination of the interlaboratory test results is as follows: NOTE 5—TheaveragebiasoftheestimatedASTMcolorrelativetoTest
MethodD1500was−0.17.Thelargestaveragebiases,−0.4to−0.5,were
13.1.1 Repeatability—The difference between successive
observed for four samples that had an ASTM color of 0.5 and red dye
test results obtained with the same apparatus under constant
concentrations that ranged from 10 to 20 mg/L.
operating conditions on identical samples would in the long
13.5 Theprecisionstatementsin13.1werederivedfromthe
run,innormalandcorrectoperationofthetestmethod,exceed
1997 interlaboratory test program. Participants analyzed 4 sets
the following value in only one case in twenty:
of undyed base fuels and 12 sets of dyed base fuel/color
r 50.22mg/L
combinations in duplicate in the ASTM color range of 0.5 to
for Solvent Red 26 equivalent dye concentrations between
3.0andSolventRed26equivalentdyeconcentrationfrom0to
0.1 and 20.0 mg/L, and
16 mg/L. Seven laboratories participated with the automatic
r 50.085ASTMcolorunits
filter apparatus and six laboratories participated with the
manual Test Method D1500 apparatus. Information on the
for samples in the ASTM color range of 0 to 5.
typesofsamplesandtheirdyeconcentrationsandcolorsarein
13.1.2 Reproducibility—The difference between two single
the research report available atASTM International Headquar-
andindependentresultsobtainedfromdifferentinstrumentson
ters. Request ASTM RR: D02-1521.
identicalsamples,wouldinthelongrun,innormalandcorrect
14. Keywords
9 14.1 ASTM color; diesel fuel, heating oil; red dye concen-
Supporting data is available from ASTM International Headquarters. Request
RR: D02-1521. tration; visible spectrophotometry
D6756–02
ANNEXES
(Mandatory Information)
A1. PROCEDURE FOR PREPARATION OF RED DYE/ASTM COLOR STANDARDS, QUALIFICATION SAMPLES, AND
QUALITY CONTROL SAMPLES
A1.
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