1、Designation: D7111 15aD7111 16Standard 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 th
2、e 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 determination of sele
3、cted elements in middle distillate fuels by inductively coupled plasmaatomic emission spectrometry (ICP-AES). The specific elements are listed in Table 1. The concentration range of this test methodis approximately 0.1 mgkg to 2.0 mg/kg. The test method may be used for concentrations outside of this
4、 range; however, theprecision statements may not be applicable. Middle distillate fuels covered in this test method have all distillation fractionscontained within the boiling range of 150 C to 390 C. This includes, but is not limited to, diesel fuels and aviation turbine fuels.1.2 This test method
5、is not intended to analyze insoluble particulates. However, very small particulate matter (smaller than amicrometre) will be carried into the plasma and be included in the quantitative analysis.1.3 This test method may give a result that is higher than the true value if an analyte is present in the
6、sample in a form whichis sufficiently volatile. For example, hexamethyldisiloxane will generate a biased high result for silicon.1.4 The values stated in SI units are to be regarded as standard.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and
7、 Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved July 1, 2015Dec. 1, 2016. Published August 2015December 2016. Originally approved in 2005. Last previous edition approved in 2015 asD7111 15.D7111 15a. DOI: 10.1520/D7111-15A.10.1520/D71
8、11-16.TABLE 1 Elements and Recommended WavelengthsElement Wavelengths, nmAluminum 308.215, 396.153Barium 455.403, 493.408Calcium 393.366Chromium 267.716, 283.563Cobalt 228.615, 236.375, 238.892Copper 324.752Iron 259.939Lithium 670.784Lead 220.353, 224.688, 283.306Magnesium 279.553Manganese 257.610Mo
9、lybdenum 202.030, 204.597, 281.616Nickel 221.648, 341.476Phosphorus 177.495, 178.287,185.944, 214.914, 213.618Palladium 340.458, 342.124Platinum 214.423Potassium 766.490Sodium 588.995Silicon 251.611Silver 328.068Strontium 407.771Tin 283.999, 189.991Titanium 334.940Vanadium 310.230Zinc 213.857This do
10、cument is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions a
11、s appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Unit
12、ed States11.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Refe
13、renced Documents2.1 ASTM Standards:2D2880 Specification for Gas Turbine Fuel OilsD3605 Test Method for Trace Metals in Gas Turbine Fuels by Atomic Absorption and Flame Emission SpectroscopyD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4306 Practice for Aviation Fuel Sample C
14、ontainers for Tests Affected by Trace ContaminationD5185 Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by InductivelyCoupled Plasma Atomic Emission Spectrometry (ICP-AES)D6299 Practice for Applying Statistical Quality Assurance and Control Charting Tech
15、niques to Evaluate Analytical Measure-ment System PerformanceD6792 Practice for Quality System in Petroleum Products and Lubricants Testing LaboratoriesD7260 Practice for Optimization, Calibration, and Validation of Inductively Coupled Plasma-Atomic Emission Spectrometry(ICP-AES) for Elemental Analy
16、sis of Petroleum Products and Lubricants2.2 Military Standard:MIL-DTL-16884 Fuel, Naval Distillate33. Terminology3.1 Definitions:3.1.1 calibration, nthe determination of the values of the significant parameters by comparison with values indicated by a setof reference standards.3.1.2 calibration curv
17、e, nthe graphical or mathematical representation of a relationship between the assigned (known) valuesof standards and the measured responses from the measurement system.3.1.3 calibration standard, na standard having an accepted value (reference value) for use in calibrating a measurementinstrument
18、or system.3.1.4 detection limit, na stated limiting value that designates the lowest concentration that can be determined with confidenceand that is specific to the analytical procedure used.3.1.5 emission spectroscopy, nmeasurement of the energy spectrum emitted by or from an object under some form
19、 of energeticstimulation; for example, light or electrical discharge.3.1.6 inductively coupled plasma, na high temperature discharge generated by passing an ionizable gas through a magneticfield induced by a radio frequency coil surrounding the tubes that carry the gas.3.1.7 radio frequency, nthe ra
20、nge of frequencies between 3 kHz and 300 GHz.3.1.8 standard, na physical or chemical reference used as a basis for comparison or calibration.3.2 Definitions of Terms Specific to This Standard:3.2.1 detection limit, nthe lowest concentration value for an element that can be determined by ICP analysis
21、 and that iscalculated by multiplying three times the standard deviation of ten repetitive element analyses of the blank solution.3.2.2 internal standard, na chemical standard having an accepted value (and added to the fuel test specimen and calibrationstandard) to determine the emission intensity r
22、atio of an element to the internal standard.4. Summary of Test Method4.1 Calibration standards are prepared by mixing organometallic standard materials in kerosine. An internal standard materialis added to the calibration standards and fuel samples. The calibration standards and the fuel samples are
23、 aspirated into theICP-AES instrument. The concentrations of the elements in the fuel are calculated by comparing emission intensity ratios of thefuel and calibration standards to the internal standard.4.2 Consult Practice D7260 regrading the optimum operation of any ICP-AES system.5. Significance a
24、nd Use5.1 Trace elemental analysis is used to indicate the level of contamination of middle distillate fuels. Trace metals in turbine fuelscan cause corrosion and deposition on turbine components at elevated temperatures. Some diesel fuels have specification limit2 For referencedASTM standards, visi
25、t theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available online at http:/quicksearch.dla.mil or http:/D7111 162requirements for trace metals t
26、o guard against engine deposits. Trace level copper in middle distillate aviation turbine fuel cansignificantly accelerate thermal instability of the fuel, leading to oxidation and production of detrimental insoluble deposits in theengine.5.2 Gas turbine fuel oil Specification D2880 provides recomme
27、nded upper limits for five trace metals (calcium, lead, sodium,potassium, and vanadium). Military specification MIL-DTL-16884 for naval distillate fuel sets requirements for maximumconcentrations of the same five metals. Both specifications designate Test Method D3605, an atomic absorption/flame emi
28、ssionmethod, for the quantitative analysis of four of the metals.Test Method D3605 does not cover potassium.This test method providesan alternative to Test Method D3605, covers potassium and a number of additional elements.5.3 There are several sources of multi-element contamination of naval distill
29、ate fuel. Sea water is pumped into the diesel fueltanks (as ballast) to trim ships.Also, some of the oilers (fuel supply ships) have dirty tanks. Corrosion products come from unlinedtanks, piping, pumps, and heat exchangers.6. Interferences6.1 Elemental wavelengths listed in Tables 1 and 2 have been
30、 found to be free of spectral interferences with all other elementslisted in Tables 1 and 2 in the concentration range of this test method.6.2 If a spectral interference does exist, then selecting an analytical wavelength other than those listed in Table 1 or Table 2 maybe used as long as the new wa
31、velength possesses appropriate sensitivity for the scope of the method.6.3 Alternatively, the ICP spectrometer manufacturers software may be used to provide corrections to interferences that cannotbe avoided by wavelength selection and background correction.6.4 An empirical method for correcting for
32、 spectral interferences is detailed in Test Method D5185, Section 6.1 (Spectral).7. Apparatus7.1 Inductively-Coupled Plasma Atomic Emission SpectrometerAny commercial sequential or simultaneous ICP-AESinstrument capable of measuring emission intensities of the elements of interest (and listed in Tab
33、le 1). A vacuum or inert gasoptical path is required for analysis of any element at wavelengths below 190 nm.7.2 NebulizerFor samples without particulates, a concentric nebulizer is recommended to provide higher sensitivity for lowconcentrations and for low sensitivity elements. For unknown samples,
34、 a Babington-type high solids nebulizer is recommendedto reduce the possibility of clogging from particulate.7.3 Spray Chamber, suitable for organic materials.7.4 Peristaltic PumpA peristaltic pump is required to provide a constant flow of liquid to the ICP. Viton pump tubing isrecommended for use w
35、ith fuels and kerosine.7.5 Membrane Filter, 47 mm diameter, 0.8 m or 1.0 m pore size.7.6 Membrane Filter Holder Assembly, for 47 mm diameter filters, 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,
36、 round.7.10 Analytical Balance, measuring to 0.0001 g.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American C
37、hemical Society where suchspecifications are available.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.4 Reagent Chemicals, American Chemical Society Specifications, Amer
38、ican Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (U
39、SPC), Rockville, MD.TABLE 2 Internal Standards, Recommended Wavelengths, andApproximate Use ConcentrationsInternalStandardWavelength,nmConcentration,mg/kgScandium 361.383 1-2Yttrium 371.029 1-5D7111 1638.2 Organometallic Standards, single element and multielement organometallic standards, nominal 10
40、0 mg/kg of each elementof interest.8.3 Internal Standard, fuel soluble yttrium, cobalt, scandium or other single element organometallic standard, not a componentof the fuel test specimen or calibration standard, nominal 5000 mg/kg.8.4 Kerosine, with analyte concentrations below the detection limits
41、of the instrument. The kerosine can be screened for thepresence of analytes as detailed in 12.1 by performing a wavelength 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. (Warni
42、ngNitrogen may be a compressed gas under high pressure.)8.7 Nitric Acid, 10 % aqueous solution. (WarningNitric acid may cause severe burns.)8.8 Quality Control (QC) Samples, preferably are portions of one or more fuel or kerosine materials that are stable andrepresentative of the samples of interest
43、. These QC samples can be used to check the validity of the testing process as describedin Section 18. If a suitable QC fuel is not available, obtain a stable QC concentrate, and dilute it with kerosine on the day of theQC check to the trace level required as described in 12.3. Use HDPE plastic bott
44、les to contain concentrated organometallicsolutions and for sodium analysis.9. Hazards9.1 Gases under high pressure and corrosive acid are used in this method. Wear appropriate personal protective equipment whenworking with nitric acid. Use only apparatus rated for handling the high gas pressures th
45、at occur in this test method.10. Sampling and Test Specimens10.1 Samples shall be taken in accordance with procedures described in Practice D4057. Suitable sample containers for aviationfuels are described in Practice D4306. Use HDPE plastic containers for sodium analysis.10.2 Samples shall be thoro
46、ughly mixed in their containers immediately prior to testing.10.3 If particulate matter is observed in the sample, filter it through a 0.8 m or 1.0 m (nylon, TFE-fluorocarbon, celluloseacetate/cellulose nitrate, or other compatible material) membrane filter into an acid-cleaned flask and retain the
47、filtrate for analysis.Follow the same filtration procedure for the kerosine blank material used for the analysis of these samples.11. Preparation of Apparatus11.1 SpectrometerPrepare the ICP spectrometer according to the manufacturers instructions and parameter settings fororganic materials and the
48、elements of interest. At least three integrations should be made for all samples (standards, blank, fuels)run. Table 1 provides recommended element wavelengths for fuels; however, other wavelengths may be used due to possibleinstrument variations or spectral interferences. The optical path can be pu
49、rged with argon or another high purity gas (for example,nitrogen) recommended by the manufacturer. Before igniting the plasma, inspect the quartz torch to make sure that it is clean. Ifcarbon build-up is observed, replace the torch and make the manufacturers recommended adjustments for this problem. Warm upthe instrument while purging the optics for the time period recommended by the ICP manufacturer. If necessary, replace theperistaltic pump tubing and adjust the solution uptake to the desired rate. Ignite the torch, then begin asp
