1、Designation: D 6756 02An American National StandardStandard Test Method forDetermination of the Red Dye Concentration and Estimationof the ASTM Color of Diesel Fuel and Heating Oil Using aPortable Visible Spectrophotometer1This standard is issued under the fixed designation D 6756; the number immedi
2、ately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This
3、test method describes the determination of the reddye concentration of diesel fuel and heating oil and theestimation of the ASTM color of undyed and red-dyed dieselfuel and heating oil. The test method is appropriate for use withdiesel fuel and heating oil of Grades 1 and 2 described inSpecification
4、s D 396, D 975, D 2880 and D 3699. Red dyeconcentrations are determined at levels equivalent to 0.1 to 20mg/L of Solvent Red 26 in samples withASTM colors rangingfrom 0.5 to 5. The ASTM color of the base fuel of red-dyedsamples with concentration levels equivalent to 0.1 to 20 mg/Lof Solvent Red 26
5、is estimated for theASTM color range from0.5 to 5. TheASTM color of undyed samples is estimated overthe ASTM color range of 0.5 to 5.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with it
6、s use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 396 Specification for Fuel Oils2D 975 Specification for Diesel Fuel Oi
7、ls2D 1500 Test Method for ASTM Color of Petroleum Prod-ucts (ASTM Color Scale)2D 2880 Specification for Gas Turbine Fuel Oils3D 3699 Specification for Kerosine3D 4052 Test Method for Density and Relative Density ofLiquids by Digital Density Meter3D 4057 Practice for Manual Sampling of Petroleum andP
8、etroleum Products3D 4177 Practice for Automatic Sampling of Petroleum andPetroleum Products3D 6045 Test Method for Color of Petroleum Products by theAutomatic Tristimulus Method4E 203 Test Method forWater UsingVolumetric Karl FischerTitration5E 1655 Practices for Infrared, Multivariate, Quantitative
9、Analysis6E 2056 Practice for Qualifying Spectrometers and Spectro-photometers for Use in Multivariate Analysis, CalibratedUsing Surrogate Mixtures63. Terminology3.1 Definitions:3.1.1 ASTM color, nan empirical definition of the color ofa petroleum liquid based on a scale of 0.5 to 8 as determinedby T
10、est Method D 1500.3.1.2 surrogate calibration, na multivariate calibrationthat is developed using a calibration set which consists ofmixtures with pre-specified and reproducible compositions thatcontain substantially fewer chemical components than thesamples which will ultimately be analyzed. E 2056
11、3.1.3 surrogate method, na standard test method that isbased on a surrogate calibration. E 20563.2 Definitions of Terms Specific to This Standard:3.2.1 red dye, nsubstance that, when added to fuel,absorbs green light and imparts a red color to the product. Forthis test method, red dyes are:3.2.1.1 p
12、roduct dyes, nalkyl derivatives of azobenzene-4-azo-2-naphthol (methyl derivatives of Color Index No. 26105)which are more soluble in diesel fuel.3.2.1.2 solvent red 26, nan azobenzene-4-azo-2-naphtholdye of a specific chemical structure that is used to gage theamount of red dye present in a given s
13、ample.4. Summary of Test Method4.1 A sample is introduced into the liquid specimen cell.The cell is placed into the light path of the apparatus. A beamof visible light is imaged through the sample onto a detector,1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products
14、and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Materials.Current edition approved Feb. 10, 2002. Published April 2002.2Annual Book of ASTM Standards, Vol 05.01.3Annual Book of ASTM Standards, Vol 05.02.4Annual Book of ASTM Stan
15、dards, Vol 05.04.5Annual Book of ASTM Standards, Vol 15.05.6Annual Book of ASTM Standards, Vol 03.06.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.and the detector response is determined. Wavelengths of thespectrum, which correlate
16、 highly with the red dye concentra-tion and the ASTM color, are selected for analysis usingselective bandpass filters. A multivariate mathematical modelconverts the absorption values from the filters to the red dyeconcentration and the estimated ASTM color.5. Significance and Use5.1 In the United St
17、ates, high sulfur content (defined by theUnited States Environmental Protection Agency (USEPA)middle distillate products and diesel fuel used for off-roadpurposes, other than aviation turbine fuel, are required bygovernment agencies to contain red dye. The dye concentrationrequired to be present in
18、high sulfur and off-road dieselproducts is regulated by the United States EnvironmentalProtection Agency and the United States Internal RevenueService, respectively.5.2 Some fuels that are readily exchanged in the markethave a color specification. The color of the base fuel is maskedby the presence
19、of the red dye. This test method provides ameans of estimating the base color of Number 1 and Number2 diesel fuel and heating oil in the presence of red dye.5.3 The test method provides a means to indicate conform-ance to contractual and legal requirements.6. Interferences6.1 The presence of coloran
20、ts other than the hydrocarbonstypical of Number 1 and 2 diesel fuel and heating oils, or thepresence of red dye other than the specified types, can interferewith the accurate determination of the red dye concentrationreported as Solvent Red 26 equivalent or the base fuel ASTMcolor.7. Apparatus7.1 Fi
21、lter Spectrophotometer, is equipped with specimenchamber, visible wavelength source, four 10 6 2 nm (fullwidth at half transmission maximum) bandpass wavelengthdiscriminating filters having center wavelengths at 450 6 2nm, 520 6 2 nm, 650 6 2 nm, and 700 6 2 nm. The bandpassfilters are used in conju
22、nction with the visible wavelengthsource to produce light in the blue, green, red, and far-redregions of the electromagnetic spectrum. A detector convertsthe transmitted light to an electronic signal that is processed byan A-D converter and a microprocessor.7,87.2 Specimen Cell, constructed of polym
23、ethacrylate or clearoptical glass having a path length of approximately 1 cm. Ifmore than one cell is used for calibration, qualification andsample measurement, the path length of the cells must bematched to 60.001 cm.8. Sampling8.1 Samples shall be taken in accordance with PracticeD 4057 or D 4177.
24、8.2 Precautions must be taken to shield the samples fromlight prior to analysis.9. Calibration and Standardization of the Apparatus9.1 The instrument is calibrated according to the proceduredescribed in Annex A2.NOTE 1The DT100C7instruments are calibrated at the factory by thevendor.9.2 The instrume
25、nt is qualified according to the proceduredescribed in Annex A3.NOTE 2The DT100C instruments are qualified at the factory by thevendor.9.2.1 If the qualification procedure is performed by thevendor, then the user shall perform a quality control checkaccording to the procedure described in Section 10
26、.10. Quality Control Check10.1 To confirm the performance of the instrument, periodi-cally measure the red dye concentration and theASTM color ofthree control samples using the procedure outlined in Section11. The quality control check standards should be analyzed atleast once a week or before the s
27、ample analysis if theinstrument is used less frequently than weekly or if theinstrument is moved to a different laboratory or field location.NOTE 3Quality control samples are available from DT100C7.10.1.1 A standard of known dye concentration and ASTMcolor is made according to the information in A1.
28、4. The set ofquality control samples shall have a low, medium, and high reddye concentration (0 to 14 6 2 mg/L) and a low, medium, andhigh ASTM color (0 to 5 ASTM color units).10.1.2 The standards are stable for at least one year whenstored in the dark in tightly sealed bottles.10.2 If the red dye c
29、oncentration determined for one of thequality control samples differs from the known value by morethan 1.0 mg/L or if the estimated ASTM color for one of thequality control samples differs from the known value by morethan 0.5 units, then the measurement system is out-of-controland cannot be used to
30、determine the red dye concentration orused to estimate the ASTM color until the cause of theout-of-control behavior is corrected.10.3 If correction of out-of-control behavior requires repairto the instrument or recalibration of the instrument, thequalification of instrument performance described inA
31、nnexA3shall be performed before the system is used to measure reddye concentration or used to estimate ASTM color.11. Procedure11.1 Prepare the filter spectrophotometer for operation inaccordance with the manufacturers instructions.11.2 Equilibrate the sample to between 20 and 25C.11.3 Fill a clean,
32、 dry specimen cell. The external opticalsurfaces must be clean. If not, wipe clean and dry with a pieceof lint-free paper (for example, lens paper).11.4 Insert the specimen cell into the cell chamber of theinstrument.11.5 Record the Solvent Red 26 equivalent concentrationand the estimated ASTM color
33、.7DT100C instruments used to develop this precision statement are availablefrom PetroSpec, Inc., 530 Main St., Acton, MA 01720.8The sole source of supply of the apparatus known to the committee at this timeis provided. If you are aware of alternative suppliers, please provide this informationto ASTM
34、 International Headquarters. Your comments will receive careful consid-eration at a meeting of the responsible technical committee,1which you may attend.D675602212. Report12.1 Report the red dye concentration to the nearest 0.1mg/L as Solvent Red 26 equivalent dye.NOTE 4The number of milligrams per
35、litre of Solvent Red 26equivalents measured by the DT100C instrument is labeled as ppm on thedisplay. The ppm unit reported by the DT100C instrument is equivalent tomg/L.12.2 Report the estimated ASTM color value as: estimatedASTM color using ASTM D 6756. Report the result to thenearest 0.1 color va
36、lue.12.2.1 The reported estimated ASTM color value can beconverted to a value that mimics the reporting convention ofthe Test Method D 1500. For estimated ASTM color valuesthat are x.0 or x.5, the estimated value is reported unchanged.For estimated color values between x.1 and x.4, round up thevalue
37、 to the nearest x.5 and place an L before the result. Forestimated color values between x.6 and x.9, round up the valueto the nearest whole number and place an L before the result.If the estimated color value is greater than 8.0, report theestimated result as 8.13. Precision and Bias13.1 Interlabora
38、tory tests of the procedure were carried outusing sixteen samples covering the red dye concentration rangeequivalent to 0 to 16 mg/L of Solvent Red 26 equivalents andcovering the range of ASTM color from 0.5 to 3.0. Sevenlaboratories participated in the interlaboratory tests. The pre-cision of this
39、procedure as determined by the statisticalexamination of the interlaboratory test results is as follows:913.1.1 RepeatabilityThe difference between successivetest results obtained with the same apparatus under constantoperating conditions on identical samples would in the longrun, in normal and corr
40、ect operation of the test method, exceedthe following value in only one case in twenty:r 5 0.22 mg/Lfor Solvent Red 26 equivalent dye concentrations between0.1 and 20.0 mg/L, andr 5 0.085 ASTM color unitsfor samples in the ASTM color range of 0 to 5.13.1.2 ReproducibilityThe difference between two s
41、ingleand independent results obtained from different instruments onidentical samples, would in the long run, in normal and correctoperation of the test method, exceed the following value inonly one case in twenty:R 5 0.86 mg/Lfor Solvent Red 26 equivalent dye concentrations between0.1 and 20.0 mg/L,
42、 andR 5 0.20 ASTM color unitsfor samples in the ASTM color range of 0 to 5.13.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod, bias has not been determined.13.3 Relative Bias (Dye Concentration)Some relativebias,9among certain
43、 samples, was observed when the SolventRed 26 concentration results were compared to the expectedSolvent Red 26 concentrations. The bias between the theoreti-cal and measured Solvent Red 26 concentration is observedwith the test samples that were made using Solvent Red 164,the chemical used to comme
44、rcially dye diesel fuel. Theobserved bias does appear to be of a systematic nature and isnot known to be related to the accuracy of this test method,since the Solvent Red 26 equivalency of the Solvent Red 164used in sample preparation has not been determined, onlyestimated.13.4 Relative Bias (ASTM C
45、olor)Relative bias,9for onesample, was observed when the color results were compared tothe Test Method D 1500 results; however, this bias is near thereproducibility of the test methods and is inconclusive. Theoverall relative bias to Test Method D 1500 is not significant.NOTE 5The average bias of th
46、e estimatedASTM color relative to TestMethod D 1500 was 0.17. The largest average biases, 0.4 to 0.5, wereobserved for four samples that had an ASTM color of 0.5 and red dyeconcentrations that ranged from 10 to 20 mg/L.13.5 The precision statements in 13.1 were derived from the1997 interlaboratory t
47、est program. Participants analyzed 4 setsof undyed base fuels and 12 sets of dyed base fuel/colorcombinations in duplicate in the ASTM color range of 0.5 to3.0 and Solvent Red 26 equivalent dye concentration from 0 to16 mg/L. Seven laboratories participated with the automaticfilter apparatus and six
48、 laboratories participated with themanual Test Method D 1500 apparatus. Information on thetypes of samples and their dye concentrations and colors are inthe research report available at ASTM International Headquar-ters. Request ASTM RR: D02-1521.14. Keywords14.1 ASTM color; diesel fuel, heating oil;
49、 red dye concen-tration; visible spectrophotometry9Supporting data is available from ASTM International Headquarters. RequestRR: D02-1521.D6756023ANNEXES(Mandatory Information)A1. PROCEDURE FOR PREPARATION OF RED DYE/ASTM COLOR STANDARDS, QUALIFICATION SAMPLES, ANDQUALITY CONTROL SAMPLESA1.1 ScopeA1.1.1 This annex is a description of the preparation of dyeconcentration and color standard samples used for calibrationand qualification. It also describes the preparation of possiblestandard samples that can be used for periodic checks.A1.2 ApparatusA1.2.1 Spectrophotome
