1、Designation: D7111 11Standard 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 D7111; the number immediately following the designation indicates the year of
2、original 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 determination of selectedeleme
3、nts 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 outside of this range; however,t
4、he 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 test method is not intended to an
5、alyze 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 in the sample in a form whichis
6、 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 use. It is theresponsibility of
7、 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:2D2880 Specification for Gas Turbine Fuel OilsD3605 Test Method for Trace Metals in Gas Turbine Fuelsby A
8、tomic Absorption and Flame Emission SpectroscopyD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4306 Practice for Aviation Fuel Sample Containers forTests Affected by Trace ContaminationD5185 Test Method for Determination of Additive Ele-ments, Wear Metals, and Contaminants in
9、Used Lubricat-ing Oils and Determination of Selected Elements in BaseOils by Inductively Coupled Plasma Atomic EmissionSpectrometry (ICP-AES)D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for
10、 Quality System in Petroleum Productsand Lubricants Testing LaboratoriesD7260 Practice for Optimization, Calibration, and Valida-tion of Inductively Coupled Plasma-Atomic EmissionSpectrometry (ICP-AES) for Elemental Analysis of Petro-leum Products and Lubricants2.2 Military Standard:1This test metho
11、d is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved June 1, 2011. Published July 2011. Originally approvedin 2005. Last previous edition approved in 2005 as D711105
12、. DOI: 10.1520/D7111-11.2For 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.TABLE 1 Elements and Recommended Wave
13、lengthsElement Wavelengths, nmAluminum 308.215, 396.153Barium 455.403, 493.408Calcium 393.366Chromium 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 588.995Silic
14、on 251.611Silver 328.068Titanium 334.940Vanadium 310.230Zinc 213.8571*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.MIL-F-16884J Military Specification, Fuel, Naval Di
15、stil-late33. Terminology3.1 Definitions: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 mathematicalrepresentation of a relationship between the assigned (kn
16、own)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 stated limiting value that desig-nates the lowest con
17、centration 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, light or electrical discharge.3.1.6 inductively co
18、upled 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 GHz.3.1.8 standard, na physical or chemical referen
19、ce 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 times the standard deviation often repetitive elem
20、ent 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. Summary of Test Method4.1 Calibration standards ar
21、e 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 concentrations of the ele-ments in the fuel are calcul
22、ated by comparing emissionintensity ratios of the fuel and calibration standards to theinternal standard.4.2 Consult Practice D7260 regrading the optimum opera-tion of any ICP-AES system.5. Significance and Use5.1 Trace elemental analysis is used to indicate the level ofcontamination of middle disti
23、llate fuels. Trace metals in turbinefuels 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 si
24、gnificantly accelerate thermal instability ofthe fuel leading to oxidation and production of detrimentalinsoluble deposits in the engine.5.2 Gas turbine fuel oil Specification D2880 provides rec-ommended upper limits for five trace metals (calcium, lead,sodium, potassium, and vanadium). Military spe
25、cificationMIL-F-16884J for naval distillate fuel sets requirements formaximum concentrations of the same five metals. Both speci-fications designate Test Method D3605, an atomic absorption/flame emission method, for the quantitative analysis of four ofthe metals. Test Method D3605 does not cover pot
26、assium. Thistest method provides an alternative to Test Method D3605,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 th
27、e oilers(fuel supply ships) have 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 co
28、ncentration range ofthis test method.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 spectr
29、ometer manufacturers soft-ware 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 D5185, Section 6.1(Spectral).7. Apparatus7.1 Inducti
30、vely-Coupled Plasma Atomic EmissionSpectrometerAny 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 n
31、m.7.2 NebulizerA Babington-type high solids nebulizer isrecommended to reduce the possibility of clogging fromparticulate.7.3 Spray Chamber, suitable for organic materials.3Naval Sea Systems Command (NAVSEA), SEA03R42, 1333 Isaac Hull Ave.,SE, Washington, DC 20376.TABLE 2 Internal Standards, Recomme
32、nded Wavelengths, andApproximate Use ConcentrationsInternalStandardWavelength,nmConcentration,mg/kgCobalt 238.892 5Scandium 361.383 1-2Yttrium 371.029 1-5D71111127.4 Peristaltic PumpA peristaltic pump is required toprovide a constant flow of liquid to the ICP. Viton pump tubingis recommended for use
33、 with fuels and kerosine.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,
34、round.7.10 Analytical Balance, measuring to 0.0001 g.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals 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 Chem
35、ical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Organometallic Standards, single element and multiele-ment organometa
36、llic standards, nominal 100 mg/kg of eachelement of interest.8.3 Internal Standard, fuel soluble yttrium, cobalt, scan-dium 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 b
37、elow the detec-tion limits of the instrument. The kerosine can be screened forthe presence of analytes as detailed in 12.1 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, 99.99
38、9 % minimum purity. (WarningNitrogen may be a compressed gas under high pressure.)8.7 Nitric Acid, 10 % aqueous solution. (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
39、 the samples of interest. These QC samplescan be used to check the validity of the testing process asdescribed in Section 18. 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.
40、Use HDPE plastic bottles to contain concentratedorganometallic solutions and for sodium analysis.9. Hazards9.1 Gases under high pressure and corrosive acid are used inthis method. Wear appropriate personal protective equipmentwhen working with nitric acid. Use only apparatus rated forhandling the hi
41、gh gas pressures that occur in this test method.10. Sampling and Test Specimens10.1 Samples shall be taken in accordance with proceduresdescribed in Practice D4057. Suitable sample containers foraviation fuels are described in Practice D4306. Use HDPEplastic containers for sodium analysis.10.2 Sampl
42、es shall be thoroughly mixed in their containersimmediately prior to testing.10.3 If particulate matter is observed in the 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
43、 and retain the filtratefor analysis. Follow the same filtration procedure for thekerosine blank material used for the analysis of these samples.11. Preparation of Apparatus11.1 SpectrometerPrepare the ICP spectrometer accord-ing to the manufacturers instructions and parameter settingsfor organic ma
44、terials and the elements of interest.At least threeintegrations should be made for all samples (standards, blank,fuels) run. Table 1 provides recommended element wave-lengths for fuels; however, other wavelengths may be used dueto possible instrument variations or spectral interferences. Theoptical
45、path can be purged with argon or another high puritygas (for example, nitrogen) recommended by the manufacturer.Before igniting 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 th
46、is problem. Warm up the instrument while purging theoptics for the time period recommended by the ICP manufac-turer. If necessary, 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
47、spray chamber. Continue plasma warm-up/stabilization forthe duration specified by the ICP manufacturer.11.2 Glassware, PlasticwareAcid clean glassware andplasticware with 10 % nitric acid (trace metal analysis grade)followed by several distilled water rinses. Do not use glasswareand plasticware that
48、 has previously contained solutions withhigh concentrations of the element(s) of interest.12. Preparation of Standards and Test Specimens12.1 Purity of KerosineSources of satisfactory high puritykerosine are commercially available. For ICP instrumentswhich provide a visual profile of emission peaks,
49、 a check maybe made of the kerosine purity by aspirating the kerosine andviewing the spectral regions where the element emissions 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, sensitivity) of the ICP instrument available. Thesingle element chosen for the internal standard should not be acomponent of the fuel test spec
