1、Designation: D 6258 09An American National StandardStandard Test Method forDetermination of Solvent Red 164 Dye Concentration inDiesel Fuels1This standard is issued under the fixed designation D 6258; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、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 procedure for determiningthe concentration of dye Solvent R
3、ed 164 in commerciallyavailable diesel and burner fuels using visible spectroscopy.NOTE 1This test method is suitable for all No. 1 and No. 2 grades inSpecifications D 396 and D 975 and for grades DMA and DMB inSpecification D 2069.1.2 The concentration ranges specified for the calibrationstandards
4、are established in 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
5、26 per thousand bbl (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
6、 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:2D 396 Specification for Fuel OilsD 975 Specification for Diesel Fuel OilsD 2069 Specification for Mar
7、ine Fuels3D 3699 Specification for KerosineD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsE 131 Terminology Relating to Molecular SpectroscopyE 169 Practices for General Techniques of Ultraviolet-Visible Quantitative AnalysisE 275 Practice for Describing and Measuring Performa
8、nceof Ultraviolet and Visible SpectrophotometersE 288 Specification for Laboratory Glass Volumetric FlasksE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 969 Specification for Glass Volumetric (Transfer) Pipets2.2 Federal Regulation:26 CFR 48.4082-1
9、(b) Federal Excise Tax Regulation3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminology E 131.4. Summary of Test Method4.1 The absorbance of each sample is recorded over aspecified wavelength range, and the scan is analyzed usingderivative analysis
10、 software to 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 wh
11、ite to nearly 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 dye
12、s absorb. Standard 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 co
13、rrections can 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.Further, the specific sections (maxima and
14、 minima) of the1This 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 approved March 1, 2009. Published March 2009. Origina
15、llyapproved in 1998. Last previous edition approved in 2004 as D 625804.2For 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 AS
16、TM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.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.second deriva
17、tive spectra employed for this analysis are afunction 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-e
18、xempt diesel fuels be dyed with an amount of Solvent 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
19、, andto detect the presence of Solvent Red 164 in taxed 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 s
20、tructure to Solvent Red 26except that it has hydrocarbon (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 produ
21、ction; however, its visiblespectrum is virtually identical 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, equipp
22、ed with automated scanning,background correction, and 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 measurem
23、ents shall be repeatable andknown to be accurate to within 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 differen
24、t specifications, for example,minimum slit width 2 to 4 nm, no data storage, diode array spectropho-tometers, and so forth, may be used if they provide demonstrablyequivalent results. Equivalence can be demonstrated by successful (withinreproducibility limits) participation in inter- or intra-labora
25、tory studiesusing this test method.6.1.1 For applicable general techniques and methods oftesting spectrophotometers to be used in this test method, referto Practices E 169 and E 275.6.2 Sample Cells (Cuvettes), one or more fused silica orglass cells having sample path length of 1.0 cm.6.3 Analytical
26、 Balance, 0.1 mg sensitivity, 60.05 mg pre-cision.6.4 Volumetric Pipettes, 1, 2, 3, 4, and 5 mL, Class A,according to Specification E 969.6.5 Volumetric Flasks, 100 mL and 250 mL, Class A,borosilicate glass, according to Specification E 288.7. Reagents7.1 Purity of ReagentsReagent grade chemicals sh
27、all beused in all tests. Unless otherwise indicated, it is 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 th
28、e reagent is ofsufficiently high purity to permit its use 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
29、certified purity, andmaximum absorbance at 512 6 20 nm.7.3 Kerosine1-K, water-white, conforming to Specifica-tion D 3699, and having a maximum absorbance against air of0.08 absorbance units over the wavelength range 450 to 750nm (1.0 cm cell, 120 nm/min scan rate, slit width 1.0 nm).(WarningFlammabl
30、e; harmful if swallowed, inhaled, orbrought into contact with 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 D 4057 in acquisition oftest sample(s).8.2 Precautions must be tak
31、en to shield the samples fromsunlight prior to analysis.NOTE 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:9.1.1 Solvent Red 26Weigh approximately 0.0750 g of thedye standard
32、 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 in the stockstandard using the following equation:4Reagent Chemicals, Americ
33、an Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the 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,
34、U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Structure of Solvent Red 26D6258092C 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 d
35、ye standard used in preparing thestock standard, purity %/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 Calibratio
36、n Standards:9.2.1 Pipet the volumes of the stock standard 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 m
37、g/L9.2.2 Determine the exact concentration of dye in 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 calibrat
38、ion standards in tightlycapped/sealed brown glass bottles 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 eac
39、h using a scan rate of 120 nm/min, maximum datarecording interval of 0.11 nm, and a maximum slit width of 1.0nm.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 p
40、lotthe second derivative spectra for each standard over 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 6 20 nm (peak
41、max, Fig. 2)561 6 20 nm (peak min, Fig. 2)NOTE 5Specific 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) from 450nm to 750 nm using the same i
42、nstrument settings employed forthe working standards and 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.10.3 Measure the amplitude difference between the deriva-tive
43、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 used andsample matrix effe
44、cts. On instruments that automaticallyrecord amplitudes at preset wavelengths, adjustments must bemade to compensate for this shift to ensure that actualminimum and maximum amplitudes are used in determiningamplitude differences.FIG. 2 Second Derivative Scans of Solvent Red 26 Dye in KerosineD625809
45、311. Calculation11.1 Prepare a calibration curve, 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 a
46、gainst the calibration curve.11.2.1 Computer 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 m
47、g/L.12. Precision and Bias512.1 PrecisionThe precision of the test method, as ob-tained by statistical examination of inter- and intra-laboratorytest results obtained in accordance with the requirements ofPractice E 691, is as follows:12.1.1 RepeatabilityWithin-laboratory precision, a quan-titative
48、expression of the random error associated with 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 repeatabi
49、lityexpression is valid for the concentration 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 ReproducibilityBetween-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 a
