1、Designation: D6258 09 (Reapproved 2014)Standard Test Method forDetermination of Solvent Red 164 Dye Concentration inDiesel Fuels1This standard is issued under the fixed designation D6258; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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. Scope1.1 This test method covers the procedure for determiningthe concentration of dye Solvent Red 164 in comm
3、erciallyavailable diesel and burner fuels using visible spectroscopy.NOTE 1This test method is suitable for all No. 1 and No. 2 grades inSpecifications D396 and D975 and for grades DMA and DMB inSpecification D2069.1.2 The concentration ranges specified for the calibrationstandards are established i
4、n response to the Internal RevenueService dyeing requirements which state that tax-exempt dieselfuel satisfies the dyeing requirement only if it contains the dyeSolvent Red 164 (and no other dye) at a concentrationspectrally equivalent to 3.9 lb of the solid dye standard SolventRed 26 per thousand b
5、bl (11.1 mg/L) of diesel fuel.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of t
6、his 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Standards:2D396 Specification for Fuel OilsD975 Specification for Diesel Fuel OilsD2069 Specification for Marine Fuels (Withdrawn
7、 2003)3D3699 Specification for KerosineD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsE131 Terminology Relating to Molecular SpectroscopyE169 Practices for General Techniques of Ultraviolet-VisibleQuantitative AnalysisE275 Practice for Describing and Measuring Performance ofUlt
8、raviolet and Visible SpectrophotometersE288 Specification for Laboratory Glass Volumetric FlasksE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE969 Specification for Glass Volumetric (Transfer) Pipets2.2 Federal Regulation:26 CFR 48.4082-1(b) Federal
9、Excise Tax Regulation3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology E131.4. Summary of Test Method4.1 The absorbance of each sample is recorded over aspecified wavelength range, and the scan is analyzed usingderivative analysis software to
10、determine the dye concentra-tion.4.2 Derivative analysis methodology is employed to mini-mize interferences caused by variations in the color andcomposition of the fuel samples regularly tested using this testmethod.4.2.1 Naturally occurring diesel test fuels range in colorfrom water white to nearly
11、 black, and many of the samplestested using this test method have also had used oils and otherproducts blended with them. These variations in color andcomposition have a significant effect upon absorbance charac-teristics of the samples in the region of the visible spectrumwhere azo dyes absorb. Sta
12、ndard operating procedures tocorrect for these background variations would involve runninga neat (undyed) sample and subtracting out the backgroundabsorbance. In most situations involved with the application ofthis test method, however, neat material is not available, so nobackground corrections can
13、 be made.4.2.2 The second derivative of the absorbance of these dyesin the visible region is a function of the fine structure of thedyes absorbance peak (versus its height or area) and isrelatively unaffected by changes in background absorbance.1This test method is under the jurisdiction of ASTM Com
14、mittee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved May 1, 2014. Published July 2014. Originally approvedin 1998. Last previous edition approved in 200
15、9 as D6258 09. DOI: 10.1520/D6258-09R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved ve
16、rsion of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Further, the specific sections (maxima and minima) of thesecond derivative spectra employed for this analysis are afunction
17、 of the fine structure of the top of the absorbance curvewhich has been found to be unique to the azo dyes.5. Significance and Use5.1 This test method was developed to provide for theenforcement of 26 CFR 48.4082-1(b), which mandates that alltax-exempt diesel fuels be dyed with an amount of Solvent
18、Red164 at a concentration that is spectrally equivalent to 3.9 lb/103bbl (11.1 mg/L) of Solvent Red 26. It is employed to verify thatthe correct amount of Solvent Red 164 is being added totax-exempt product at terminals or refineries prior to sale, andto detect the presence of Solvent Red 164 in tax
19、ed productintended for on-road use.5.1.1 Solvent Red 26 is the azo dye shown in Fig. 1.Itisthestandard against which the concentration of Solvent Red 164 ismeasured because it is available in a certified pure form.Solvent Red 164 is identical in structure to Solvent Red 26except that it has hydrocar
20、bon (alkyl) chains incorporated toincrease its solubility in diesel and burner fuels. The exactcomposition of Solvent Red 164 will vary from manufacturerto manufacturer and lot to lot depending upon the extent ofalkylation that occurs during production; however, its visiblespectrum is virtually iden
21、tical to the spectrum of Solvent Red26. Solvent Red 164 is employed in the field (instead ofSolvent Red 26) to dye tax-exempt diesel and burner fuelsbecause of its higher solubility and relatively low cost.6. Apparatus6.1 Spectrophotometer, equipped with automated scanning,background correction, and
22、 electronic data storage capabilities,and the ability to automatically record absorbance or transmit-tance of solutions in the spectral region from 400 to 800nanometers (nm) with a spectral slit width of 1.0 nm or less(Note 2). Wavelength measurements shall be repeatable andknown to be accurate to w
23、ithin 60.2 nm or less at deuteriumpeak 656.1 nm. In the absorbance range from 0.01 to 1.0,absorbance measurements shall have a photometric accuracy of60.005 or less and a photometric repeatability of 60.002 orless.NOTE 2Instruments having different specifications, for example,minimum slit width 2 to
24、 4 nm, no data storage, diode arrayspectrophotometers, and so forth, may be used if they provide demonstra-bly equivalent results. Equivalence can be demonstrated by successful(within reproducibility limits) participation in inter- or intra-laboratorystudies using this test method.6.1.1 For applicab
25、le general techniques and methods oftesting spectrophotometers to be used in this test method, referto Practices E169 and E275.6.2 Sample Cells (Cuvettes), one or more fused silica orglass cells having sample path length of 1.0 cm.6.3 Analytical Balance, 0.1 mg sensitivity, 60.05 mg pre-cision.6.4 V
26、olumetric Pipettes, 1, 2, 3, 4, and 5 mL, Class A,according to Specification E969.6.5 Volumetric Flasks, 100 mL and 250 mL, Class A,borosilicate glass, according to Specification E288.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it i
27、s intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Societywhere such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use
28、 without lessening theaccuracy of the determination.7.2 Solvent Red 26 (Dye Standard)Dye, Color IndexSolvent Red 26, 1-2,5-dimethyl-4-(2-methylphenyl)azophenylazo-2-naphthol, Chemical Abstract Services Reg-istry No. 4477-79-6, dry powder with certified purity, andmaximum absorbance at 512 6 20 nm.7.
29、3 Kerosine1-K, water-white, conforming to Specifica-tion D3699, and having a maximum absorbance against air of0.08 absorbance units over the wavelength range 450 to750 nm (1.0 cm cell, 120 nm/min scan rate, slit width 1.0 nm).(WarningFlammable; harmful if swallowed, inhaled, orbrought into contact w
30、ith skin or eyes.)7.4 Xylene(WarningExtremely flammable; harmful ifswallowed, inhaled, or brought into contact with skin or eyes.)8. Sampling8.1 Use the principles of Practice D4057 in acquisition oftest sample(s).8.2 Precautions must be taken to shield the samples fromsunlight prior to analysis.NOT
31、E 3Studies have shown that exposure to direct sunlight will showa decrease in dye concentration over time.9. Calibration and Standardization9.1 Preparation of Stock Standard:4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the
32、 testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Structure of Solvent Red 26D6258 09
33、(2014)29.1.1 Solvent Red 26 Weigh approximately 0.0750 g ofthe dye standard to the nearest 0.1 mg on an analytical balance,quantitatively transfer the dye to a 250 mL volumetric flask,and dilute to mark with xylene. Mix the prepared solutionthoroughly.9.1.2 Determine the exact concentration of dye i
34、n the stockstandard using the following equation:C 5M!P!1000!0.250(1)where:C = concentration of active dye ingredient in the stockstandard, mg/L,M = mass of certified dye standard used in preparing thestock standard, g, andP = purity of certified dye standard used in preparing thestock standard, pur
35、ity %/100, for example, for a 99.0% Solvent Red 26 material, P = 0.99.9.1.3 Store the stock standard in tightly capped/sealedbrown glass bottles and store in a dark place when not in useto prevent deterioration.9.2 Preparation of Working Calibration Standards:9.2.1 Pipet the volumes of the stock sta
36、ndard specifiedbelow into separate 100 mL volumetric flasks and dilute tovolume with kerosine.Volume of Stock Approximate ConcentrationStandard/100 mL of Working Standards0.0 mL 0 mg/L1.0 mL 3 mg/L2.0 mL 6 mg/L3.0 mL 9 mg/L4.0 mL 12 mg/L5.0 mL 15 mg/L9.2.2 Determine the exact concentration of dye in
37、 eachworking standard using the following equation:Cs 5V!Cm!100(2)where:Cs = concentration of each working standard, mg/L,V = volume of stock standard, mL, andCm = concentration of active dye in stock standard, mg/L.9.2.3 Store the working calibration standards in tightlycapped/sealed brown glass bo
38、ttles and store in a dark placewhen not in use to prevent deterioration.9.3 Using a clean 1.0 cm sample cell, scan each of theworking standards against air (empty reference sample com-partment) from 450 nm to 750 nm, recording the absorbancefor each using a scan rate of 120 nm/min, maximum datarecor
39、ding interval of 0.11 nm, and a maximum slit width of1.0 nm.NOTE 4Other instrument conditions may be used if they can bedemonstrated to give equivalent results to this test method (see Note 2).9.4 Using derivative analysis software, calculate and plotthe second derivative spectra for each standard o
40、ver thiswavelength range using an instrument noise level dampeningsetting of sufficient level to provide a smooth second derivativecurve.9.5 Measure the amplitude difference for the maximum andminimum listed below:Solvent Red 26: 538 20 nm (peak max, Fig. 2)561 20 nm (peak min, Fig. 2)NOTE 5Specific
41、 amplitude units employed will vary, depending oninstrumentation or software used, or both.10. Procedure10.1 Using a clean 1.0 cm sample cell, scan the sampleagainst air (empty reference sample compartment) from450 nm to 750 nm using the same instrument settings em-ployed for the working standards a
42、nd record the absorbance.10.2 Using derivative analysis software and the same noiselevel dampening settings used in 9.4, calculate and plot thesecond derivative spectrum of the sample.FIG. 2 Second Derivative Scans of Solvent Red 26 Dye in KerosineD6258 09 (2014)310.3 Measure the amplitude differenc
43、e between the deriva-tive maximum and minimum specified in 9.5 (see Note 5).10.3.1 The wavelengths of the derivative minima andmaxima for the dye in actual diesel fuel samples normally varyfrom those observed for the working standards due to varia-tions in the composition of the Solvent Red 164 dye
44、used andsample matrix effects. On instruments that automatically re-cord amplitudes at preset wavelengths, adjustments must bemade to compensate for this shift to ensure that actualminimum and maximum amplitudes are used in determiningamplitude differences.11. Calculation11.1 Prepare a calibration c
45、urve, plotting the amplitudedifference for each working calibration standard on the y axisversus the dye concentration on the x axis.11.2 Determine the concentration of dye in the sample bycomparing the amplitude difference measured in 10.3 for thesample against the calibration curve.11.2.1 Computer
46、 systems/software having appropriate mul-tipoint calibration program capabilities may be used instead ofa manual interpolation from calibration curves.11.3 Report the dye concentration results for the sample inmg/L to one decimal place, for example, 11.1 mg/L.12. Precision and Bias512.1 PrecisionThe
47、 precision of the test method, as ob-tained by statistical examination of inter- and intra-laboratorytest results obtained in accordance with the requirements ofPractice E691, is as follows:12.1.1 Repeatability Within-laboratory precision, a quan-titative expression of the random error associated wi
48、th a singleoperator in a given laboratory obtaining repetitive results withthe same apparatus under constant operating conditions onidentical test material. It is defined as the difference betweentwo such results at the 95 % confidence level. The repeatabilityexpression is valid for the concentratio
49、n range covered by theinterlaboratory study samples (1.20 to 18.2 mg/L).5Repeatability r! 5 0.1847 x!0.5(3)where:x = mean dye concentration (mg/L) of two results from thesame laboratory.12.1.2 Reproducibility Between-laboratory precision, aquantitative expression of the random error associated withdifferent operators using different test apparatus in differentlaboratories and obtaining test results when applying the samemethod. It is defined as the 95 % confidence limit for thedifference between two such single and independent results.The reproduci
