1、Designation: D6756 09aStandard 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 D6756; the number immediately following the designatio
2、n 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 () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determi
3、nation of the red dyeconcentration of diesel fuel and heating oil and the estimationof the ASTM color of undyed and red-dyed diesel fuel andheating oil. The test method is appropriate for use with dieselfuel and heating oil of Grades 1 and 2 described in Specifica-tions D396, D975, D2880 and D3699.
4、Red dye concentrationsare determined at levels equivalent to 0.1 to 20 mg/Lof SolventRed 26 in samples with ASTM colors ranging from 0.5 to 5.The ASTM color of the base fuel of red-dyed samples withconcentration levels equivalent to 0.1 to 20 mg/L of SolventRed 26 is estimated for the ASTM color ran
5、ge from 0.5 to 5.The ASTM color of undyed samples is estimated over theASTM color range of 0.5 to 5.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if
6、any, associated with its 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:2D396 Specification for Fuel OilsD975 Specificati
7、on for Diesel Fuel OilsD1500 Test Method forASTM Color of Petroleum Products(ASTM Color Scale)D2880 Specification for Gas Turbine Fuel OilsD3699 Specification for KerosineD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD4057 Practice for Manual Samp
8、ling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6045 Test Method for Color of Petroleum Products by theAutomatic Tristimulus MethodE203 Test Method for Water Using Volumetric Karl FischerTitrationE1655 Practices for Infrared Multivariat
9、e QuantitativeAnalysisE2056 Practice for Qualifying Spectrometers and Spectro-photometers for Use in Multivariate Analyses, CalibratedUsing Surrogate Mixtures3. Terminology3.1 Definitions:3.1.1 ASTM color, nthe name of an empirical scale ofexpressing the color of a petroleum liquid darker than Saybo
10、ltcolor based on a scale of 0.5 (lightest) to 8 Dil (darkest) anddetermined by Test Method D1500.3.1.2 surrogate calibration, na multivariate calibrationthat is developed using a calibration set which consists ofmixtures with pre-specified and reproducible compositions thatcontain substantially fewe
11、r chemical components than thesamples which will ultimately be analyzed. E20563.1.3 surrogate method, na standard test method that isbased on a surrogate calibration. E20563.2 Definitions of Terms Specific to This Standard:3.2.1 red dye, nsubstance that, when added to fuel,absorbs green light and im
12、parts a red color to the product. Forthis test method, red dyes are:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition
13、approved Dec. 1, 2009. Published February 2010. Originallyapproved in 2002. Last previous edition approved in 2009 as D675609. DOI:10.1520/D6756-09a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda
14、rds volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1.1 product dyes, nalkyl de
15、rivatives 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 sample.4. Summary of Te
16、st 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,and the detector response is determined. Wavelengths of thespectrum, which correlate highly with the red dye
17、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 States, high sulfur content
18、 (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 high sulfur and off-road
19、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 of the red dye. This test
20、 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 colorants other than the hydroca
21、rbonstypical 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 Filter Spectrophotometer, i
22、s 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 conjunction with the visible w
23、avelengthsource 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.3,47.2 Specimen Cell, constructed of polymethacrylate or clearoptic
24、al 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 PracticeD4057 or D4177.8.2 Precautions must be tak
25、en 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 DT100C3instruments are calibrated at the factory by thevendor.9.2 The instrument is qualified according t
26、o 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 10.10. Quality Control Check1
27、0.1 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 sample analysis if theinstru
28、ment 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 DT100C3.10.1.1 A standard of known dye concentration and ASTMcolor is made according to the information in A1.4. The set ofquality contro
29、l 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 concentration determined for
30、 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 determine the red dye conce
31、ntration 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, the3DT100C instruments used to develop this precision statement are availablefrom P
32、etroSpec, Inc., 530 Main St., Acton, MA 01720.4The sole source of supply of the apparatus known to the committee at this timeis PetroSpec, Inc. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideratio
33、n at a meeting of the responsible technical committee,1whichyou may attend.D6756 09a2qualification of instrument performance described inAnnexA3shall be performed before the system is used to measure reddye concentration or used to estimate ASTM color.11. Procedure11.1 Prepare the filter spectrophot
34、ometer for operation inaccordance with the manufacturers instructions.11.2 Equilibrate the sample to between 20 and 25C.11.3 Fill a clean, 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 th
35、e specimen cell into the cell chamber of theinstrument.11.5 Record the Solvent Red 26 equivalent concentrationand the estimated ASTM color.12. 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 litre of Solvent Red 2
36、6equivalents 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 D6756. Report the result to thenearest 0.1 color value.12.2.1 The reported
37、 estimated ASTM color value can beconverted to a value that mimics the reporting convention ofthe Test Method D1500. For estimatedASTM color values thatare x.0 or x.5, the estimated value is reported unchanged. Forestimated color values between x.1 and x.4, round up the valueto the nearest x.5 and p
38、lace 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 Interlaboratory tests of the procedu
39、re 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 procedure as determined b
40、y the statisticalexamination of the interlaboratory test results is as follows:513.1.1 RepeatabilityThe difference between successivetest results obtained with the same apparatus under constantoperating conditions on identical samples would in the longrun, in normal and correct operation of the test
41、 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 singleand independent resu
42、lts 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, andR 5 0.20 ASTM color u
43、nitsfor 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,5among certain samples, was observed wh
44、en 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 commercially dye diesel fuel.
45、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 Color)Relative bias,5for o
46、nesample, was observed when the color results were compared tothe Test Method D1500 results; however, this bias is near thereproducibility of the test methods and is inconclusive. Theoverall relative bias to Test Method D1500 is not significant.NOTE 5The average bias of the estimatedASTM color relat
47、ive to TestMethod D1500 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 test program. Participants an
48、alyzed 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 laboratories participated w
49、ith themanual Test Method D1500 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; red dye concen-tration; visible spectrophotometry5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1521.D6756 09a3ANNEXES(Mandatory Information)A1. PROCEDURE FOR PREPARATION OF RED DYE/ASTM COLOR STANDARDS, QUALIFICATION
