ASTM D7111-2005 Standard Test Method for Determination of Trace Elements in Middle Distillate Fuels by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)《用感应耦合等离子体原子.pdf

1、Designation: D 7111 05An American National StandardStandard Test Method forDetermination of Trace Elements in Middle Distillate Fuelsby Inductively Coupled Plasma Atomic EmissionSpectrometry (ICP-AES)1This standard is issued under the fixed designation D 7111; the number immediately following the de

2、signation 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 test method covers the

3、 determination of selectedelements in middle distillate fuels by inductively coupledplasma atomic emission spectrometry (ICP-AES). The specificelements are listed in Table 1. The concentration range of thistest method is approximately 0.1 to 2.0 mg/kg. The test methodmay be used for concentrations o

4、utside of this range; however,the precision statements may not be applicable. Middle distil-late fuels covered in this test method have all distillationfractions contained within the boiling range of 150 to 390C.This includes, but is not limited to, diesel fuels and aviationturbine fuels.1.2 This te

5、st method is not intended to analyze insolubleparticulates. However, very small particulate matter (smallerthan a micrometre) will be carried into the plasma and beincluded in the quantitative analysis.1.3 This test method may give a result that is higher than thetrue value if an analyte is present

6、in the sample in a form whichis sufficiently volatile. For example, hexamethyldisiloxane willgenerate a biased high result for silicon.1.4 The values stated in SI units are to be regarded asstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its

7、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:2D 2880 Specification for Gas Turbine Fuel OilsD 3605 Test Method for Trac

8、e Metals in Gas Turbine Fuelsby Atomic Absorption and Flame Emission SpectroscopyD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4306 Practice for Aviation Fuel Sample Containers forTests Affected by Trace ContaminationD 5185 Test Method for Determination of Additive Ele-ment

9、s, Wear Metals, and Contaminants in Used Lubricat-ing Oils and Determination of Selected Elements in BaseOils by Inductively Coupled Plasma Atomic EmissionSpectrometry (ICP-AES)D 6299 Practice for Applying Statistical Quality AssuranceTechniques to Evaluate Analytical Measurement SystemPerformanceD

10、6792 Guide for Quality System in Petroleum Productsand Lubricants Testing Laboratories2.2 Military Standard:MIL-F-16884J Military Specification, Fuel, Naval Distil-late33. Terminology3.1 Definitions:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants

11、 and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved April 1, 2005. Published May 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume i

12、nformation, refer to the standards Document Summary page onthe ASTM website.3Naval Sea Systems Command (NAVSEA), SEA03R42, 1333 Isaac Hull Ave.,SE, Washington, DC 20376.TABLE 1 Elements and Recommended WavelengthsElement Wavelengths, nmAluminum 308.215, 396.153Barium 455.403, 493.408Calcium 393.366C

13、hromium 267.716, 283.563Copper 324.752Iron 259.939Lithium 670.784Lead 224.688, 283.306Magnesium 279.553Manganese 257.610Molybdenum 204.597, 281.616Nickel 221.648, 341.476Potassium 766.490Sodium 588.995Silicon 251.611Silver 328.068Titanium 334.940Vanadium 310.230Zinc 213.8571Copyright ASTM Internatio

14、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 calibration, nthe determination of the values of thesignificant parameters by comparison with values indicated bya set of reference standards.3.1.2 calibration curve, nthe graphical or mathematicalrepresen

15、tation of a relationship between the assigned (known)values of standards and the measured responses from themeasurement system.3.1.3 calibration standard, na standard having an ac-cepted value (reference value) for use in calibrating a measure-ment instrument or system.3.1.4 detection limit, na stat

16、ed limiting value that desig-nates the lowest concentration that can be determined withconfidence and that is specific to the analytical procedure used.3.1.5 emission spectroscopy, nmeasurement of the energyspectrum emitted by or from an object under some form ofenergetic stimulation; for example, l

17、ight or electrical discharge.3.1.6 inductively coupled plasma, na high temperaturedischarge generated by passing an ionizable gas through amagnetic field induced by a radio frequency coil surroundingthe tubes that carry the gas.3.1.7 radio frequency, nthe range of frequencies between3 kHz and 300 GH

18、z.3.1.8 standard, na physical or chemical reference used asa basis for comparison or calibration.3.2 Definitions of Terms Specific to This Standard:3.2.1 detection limit, nthe lowest concentration value foran element that can be determined by ICP analysis and that iscalculated by multiplying three t

19、imes the standard deviation often repetitive element analyses of the blank solution.3.2.2 internal standard, na chemical standard having anaccepted value (and added to the fuel test specimen andcalibration standard) to determine the emission intensity ratioof an element to the internal standard.4. S

20、ummary of Test Method4.1 Calibration standards are prepared by mixing organo-metallic standard materials in kerosine. An internal standardmaterial is added to the calibration standards and fuel samples.The calibration standards and the fuel samples are aspiratedinto the ICP-AES instrument. The conce

21、ntrations of the ele-ments in the fuel are calculated by comparing emissionintensity ratios of the fuel and calibration standards to theinternal standard.5. Significance and Use5.1 Trace elemental analysis is used to indicate the level ofcontamination of middle distillate fuels. Trace metals in turb

22、inefuels can cause corrosion and deposition on turbine compo-nents at elevated temperatures. Some diesel fuels have speci-fication limit requirements for trace metals to guard againstengine deposits. Trace level copper in middle distillate aviationturbine fuel can significantly accelerate thermal in

23、stability ofthe fuel leading to oxidation and production of detrimentalinsoluble deposits in the engine.5.2 Gas turbine fuel oil Specification D 2880 providesrecommended upper limits for five trace metals (calcium, lead,sodium, potassium, and vanadium). Military specificationMIL-F-16884J for naval d

24、istillate fuel sets requirements formaximum concentrations of the same five metals. Both speci-fications designate Test Method D 3605, an atomic absorption/flame emission method, for the quantitative analysis of four ofthe metals. Test Method D 3605 does not cover potassium. Thistest method provides

25、 an alternative to Test Method D 3605,covers potassium and a number of additional elements.5.3 There are several sources of multi-element contamina-tion of naval distillate fuel. Sea water is pumped into the dieselfuel tanks (as ballast) to trim ships. Also, some of the oilers(fuel supply ships) hav

26、e dirty tanks. Corrosion products comefrom unlined tanks, piping, pumps, and heat exchangers.6. Interferences6.1 Elemental wavelengths listed in Tables 1 and 2 havebeen found to be free of spectral interferences with all otherelements listed in Tables 1 and 2 in the concentration range ofthis test m

27、ethod.6.2 If a spectral interference does exist, then selecting ananalytical wavelength other than those listed in Table 1 orTable 2 may be used as long as the new wavelength possessesappropriate sensitivity for the scope of the method.6.3 Alternatively, the ICP spectrometer manufacturers soft-ware

28、may be used to provide corrections to interferences thatcannot be avoided by wavelength selection and backgroundcorrection.6.4 An empirical method for correcting for spectral inter-ferences is detailed in Test Method D 5185, Section 6.1(Spectral).7. Apparatus7.1 Inductively-Coupled Plasma Atomic Emi

29、ssionSpectrometerAny commercial sequential or simultaneousICP-AES instrument capable of measuring emission intensitiesof the elements of interest (and listed in Table 1). A vacuum orinert gas optical path is required for analysis of any element atwavelengths below 190 nm.7.2 NebulizerA Babington-typ

30、e high solids nebulizer isrecommended to reduce the possibility of clogging fromparticulate.7.3 Spray Chamber, suitable for organic materials.7.4 Peristaltic PumpA peristaltic pump is required toprovide a constant flow of liquid to the ICP. Viton pump tubingis recommended for use with fuels and kero

31、sine.7.5 Membrane Filter, 47 mm diameter, 0.8 m or 1.0 mpore size.7.6 Membrane Filter Holder Assembly, for 47 mm diameterfilters, with filtration flask.7.7 Pipette, 1000 L.7.8 Volumetric Flasks, 25 mL and 50 mL, glass.7.9 Glass or High Density Polyethylene (HDPE) Bottles,125 mL, round.TABLE 2 Intern

32、al Standards, Recommended Wavelengths, andApproximate Use ConcentrationsInternalStandardWavelength,nmConcentration,mg/kgCobalt 238.892 5Scandium 361.383 1-2Yttrium 371.029 1-5D71110527.10 Analytical Balance, measuring to 0.0001 g.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals

33、 shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the rea

34、gent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Organometallic Standards, single element and multiele-ment organometallic standards, nominal 100 mg/kg of eachelement of interest.8.3 Internal Standard, fuel soluble yttrium, cobalt, scan-dium

35、 or other single element organometallic standard, not acomponent of the fuel test specimen or calibration standard,nominal 5000 mg/kg.8.4 Kerosine, with analyte concentrations below the detec-tion limits of the instrument. The kerosine can be screened forthe presence of analytes as detailed in 12.1

36、by performing awavelength scan for analyte wavelengths.8.5 Argon Gas, 99.995 % minimum purity. (WarningArgon may be a compressed gas under high pressure).8.6 Nitrogen Gas, 99.999 % minimum purity. (WarningNitrogen may be a compressed gas under high pressure).8.7 Nitric Acid, 10 % aqueous solution. (

37、WarningNitricacid may cause severe burns).8.8 Quality Control (QC) Samples, preferably are portionsof one or more fuel or kerosine materials that are stable andrepresentative of the samples of interest. These QC samplescan be used to check the validity of the testing process asdescribed in Section 1

38、8. If a suitable QC fuel is not available,obtain a stable QC concentrate, and dilute it with kerosine onthe day of the QC check to the trace level required as describedin 12.3. Use HDPE plastic bottles to contain concentratedorganometallic solutions and for sodium analysis.9. Hazards9.1 Gases under

39、high pressure and corrosive acid are used inthis method. Wear appropriate personal protective equipmentwhen working with nitric acid. Use only apparatus rated forhandling the high gas pressures that occur in this test method.10. Sampling and Test Specimens10.1 Samples shall be taken in accordance wi

40、th proceduresdescribed in Practice D 4057. Suitable sample containers foraviation fuels are described in Practice D 4306. Use HDPEplastic containers for sodium analysis.10.2 Samples shall be thoroughly mixed in their containersimmediately prior to testing.10.3 If particulate matter is observed in th

41、e sample, filter itthrough a 0.8 m or 1.0 m (nylon, TFE-fluorocarbon, cellu-lose acetate/cellulose nitrate, or other compatible material)membrane filter into an acid-cleaned flask and retain the filtratefor analysis. Follow the same filtration procedure for thekerosine blank material used for the an

42、alysis of these samples.11. Preparation of Apparatus11.1 SpectrometerPrepare the ICP spectrometer accord-ing to the manufacturers instructions and parameter settingsfor organic materials and the elements of interest.At least threeintegrations should be made for all samples (standards, blank,fuels) r

43、un. Table 1 provides recommended element wave-lengths for fuels; however, other wavelengths may be used dueto possible instrument variations or spectral interferences. Theoptical path can be purged with argon or another high puritygas (for example, nitrogen) recommended by the manufacturer.Before ig

44、niting the plasma, inspect the quartz torch to makesure that it is clean. If carbon build-up is observed, replace thetorch and make the manufacturers recommended adjustmentsfor this problem. Warm up the instrument while purging theoptics for the time period recommended by the ICP manufac-turer. If n

45、ecessary, replace the peristaltic pump tubing andadjust the solution uptake to the desired rate. Ignite the torch,then begin aspirating kerosine through the nebulizer and intothe spray chamber. Continue plasma warm-up/stabilization forthe duration specified by the ICP manufacturer.11.2 Glassware, Pl

46、asticwareAcid clean glassware andplasticware with 10 % nitric acid (trace metal analysis grade)followed by several distilled water rinses. Do not use glasswareand plasticware that has previously contained solutions withhigh concentrations of the element(s) of interest.12. Preparation of Standards an

47、d Test Specimens12.1 Purity of KerosineSources of satisfactory high puritykerosine are commercially available. For ICP instrumentswhich provide a visual profile of emission peaks, a check maybe made of the kerosine purity by aspirating the kerosine andviewing the spectral regions where the element e

48、missions ofinterest are to be found. The absence of emission peaks in theseregions is evidence that the purity is satisfactory.12.2 Internal Standard Stock Solution:12.2.1 The analysts selection of the single element internalstandard may be influenced by the capabilities (wavelengthavailability, sen

49、sitivity) of the ICP instrument available. Thesingle element chosen for the internal standard should not be acomponent of the fuel test specimen or calibration standard.Organometallic yttrium has performed well as an internalstandard for this test method and is recommended. Table 2 listsinternal standards, their recommended wavelengths, and theirapproximate use concentrations for this test method.12.2.2 Prepare a stock solution of the internal standard byweight from a 5000 mg/kg single element organometallicstandard material and kerosine. Prepare a concentr