ASTM D5708-2011 3125 Standard Test Methods for Determination of Nickel Vanadium and Iron in Crude Oils and Residual Fuels by Inductively Coupled Plasma (ICP) Atomic Emission Spectr.pdf

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1、Designation: D5708 11Standard Test Methods forDetermination of Nickel, Vanadium, and Iron in Crude Oilsand Residual Fuels by Inductively Coupled Plasma (ICP)Atomic Emission Spectrometry1This standard is issued under the fixed designation D5708; the number immediately following the designation indica

2、tes 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 () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover the determination

3、of nickel,vanadium, and iron in crude oils and residual fuels byinductively coupled plasma (ICP) atomic emission spectrom-etry. Two different test methods are presented.1.2 Test Method A (Sections 7-11 and 18-22)ICP is usedto analyze a sample dissolved in an organic solvent. This testmethod uses oil

4、-soluble metals for calibration and does notpurport to quantitatively determine or detect insoluble particu-lates.1.3 Test Method B (Sections 12-22)ICP is used to analyzea sample that is decomposed with acid.1.4 The concentration ranges covered by these test methodsare determined by the sensitivity

5、of the instruments, theamount of sample taken for analysis, and the dilution volume.A specific statement is given in 15.2. Typically, the lowconcentration limits are a few tenths of a mg/kg. Precision dataare provided for the concentration ranges specified in Section21.1.5 The values stated in SI un

6、its are to be regarded asstandard. The values given in parentheses are for informationonly.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practi

7、ces and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1548 Test Method for Vanadium in Navy Special FuelOil3D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for A

8、utomatic Sampling of Petroleum andPetroleum ProductsD5185 Test Method for Determination of Additive Ele-ments, Wear Metals, and Contaminants in Used Lubricat-ing Oils and Determination of Selected Elements in BaseOils by Inductively Coupled Plasma Atomic EmissionSpectrometry (ICP-AES)D6299 Practice

9、for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD7260 Practice for Optimization, Calibration, and Valida-tion of Inductively Coupled Plasma-Atomic EmissionSpectrometry (ICP-AES) for Elemental Analysis of Petro-leum Product

10、s and Lubricants3. Summary of Test Method3.1 Test Method AApproximately 10 g of the sample aredissolved in an organic solvent (WarningCombustible. Va-por is harmful.) to give a specimen solution containing 10 %(m/m) of sample. The solution is nebulized into the plasma,and the intensities of the emit

11、ted light at wavelengths charac-teristic of the analytes are measured sequentially or simultane-ously. The intensities are related to concentrations by theappropriate use of calibration data.3.2 Test Method BOne to 20 g of sample are weighed intoa beaker and decomposed with concentrated sulfuric aci

12、d(WarningPoison. Causes severe burns. Harmful or fatal ifswallowed or inhaled.) by heating to dryness. Great care mustbe used in this decomposition because the acid fumes arecorrosive and the mixture is potentially flammable. The re-sidual carbon is burned off by heating at 525C in a mufflefurnace.

13、The inorganic residue is digested with nitric acid(WarningPoison. Causes severe burns. Harmful or fatal if1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edit

14、ion approved June 1, 2011. Published July 2011. Originally approvedin 1995. Last previous edition approved in 2005 as D570805. DOI: 10.1520/D5708-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda

15、rds volume information, refer to the standards Document Summary page onthe ASTM 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 Driv

16、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.swallowed or inhaled.), evaporated to incipient dryness, dis-solved in dilute nitric acid, and made up to volume. Thesolution is nebulized into the plasma of an atomic emissionspectrometer. The intensities of light emitted at characteri

17、sticwavelengths of the metals are measured sequentially or simul-taneously. These intensities are related to concentrations by theappropriate use of calibration data.4. Significance and Use4.1 These test methods cover, in single procedures, thedetermination of Ni, V, and Fe in crude oils and residua

18、l oils.These test methods complement Test Method D1548, whichcovers only the determination of vanadium.4.2 When fuels are combusted, vanadium present in the fuelcan form corrosive compounds. The value of crude oils can bedetermined, in part, by the concentrations of nickel, vanadium,and iron. Nickel

19、 and vanadium, present at trace levels inpetroleum fractions, can deactivate catalysts during processing.These test methods provide a means of determining theconcentrations of nickel, vanadium, and iron.5. Purity of Reagents5.1 Reagent grade chemicals shall be used in all tests.Unless otherwise indi

20、cated, it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where suchspecifications are available.4Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit it

21、s use without lessening the accuracy ofthe determination.5.2 When determining metals at concentrations less than 1mg/kg, use ultra-pure reagents.5.3 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Type II of Specification D1193.6. S

22、ampling and Sample Handling6.1 The objective of sampling is to obtain a sample fortesting purposes that is representative of the entire quantity.Thus, take samples in accordance with the instructions inPractice D4057 or D4177. Do not fill the sample containermore than two-thirds full.6.2 Prior to we

23、ighing, stir the sample and manually shakethe sample container. If the sample does not readily flow atroom temperature, heat the sample in a drying oven at 80C orat another safe temperature.TEST METHOD AICP WITH AN ORGANIC SOLVENT SPECIMENSOLUTION7. Apparatus7.1 Inductively Coupled Plasma Atomic Emi

24、ssionSpectrometerEither a sequential or simultaneous spectrom-eter, equipped with a quartz torch and radio-frequency genera-tor to form and sustain the plasma, is suitable.7.2 NebulizerThe use of a high-solids nebulizer is op-tional but strongly recommended. This type of nebulizerminimizes the proba

25、bility of clogging. A concentric glassnebulizer can also be used.7.3 Peristaltic PumpThis pump is required for non-aspirating nebulizers and optional for aspirating nebulizers.The pump must achieve a flow rate in the range of 0.5 to 3mL/min. The pump tubing must be able to withstand at least a6 h ex

26、posure to the solvent. Fluoroelastomer copolymer tubingis recommended.57.4 Specimen Solution Containers, glass or plastic vials orbottles with screw caps having a capacity of appropriate size.One hundred millilitre glass bottles are satisfactory.8. Reagents8.1 Dilution SolventMixed xylenes, o-xylene

27、, tetralin andmixed paraffin-aromatic solvents are satisfactory. Solvent pu-rity can affect analytical accuracy when the sample containslow concentrations (typically, a few mg/kg) of the analytes.8.2 Mineral OilA high-purity oil such as U.S.P. white oil.8.3 Organometallic StandardsPre-prepared multi

28、elementconcentrates containing 100 mg/kg concentrations of eachelement are satisfactory.8.4 Quality Control (QC) Samples, preferably are portionsof one or more liquid petroleum materials that are stable andrepresentative of the samples of interest. These QC samplescan be used to check the validity o

29、f the testing process asdescribed in Section 19.9. Preparation of Standards and Specimens9.1 BlankPrepare a blank by diluting mineral oil withdilution solvent. The concentration of mineral oil must be 10 %(m/m). Mix well.9.2 Check StandardUsing organometallic standards, min-eral oil, and dilution so

30、lvent, prepare a check standard tocontain analyte concentrations approximately the same asexpected in the specimens. The concentration of oil in thecheck standard must be 10 % (m/m).9.3 Test SpecimenWeigh a portion of well-mixed sampleinto a container and add sufficient solvent to achieve a sampleco

31、ncentration of 10 % (m/m). Mix well.9.4 Working StandardPrepare an instrument calibrationstandard that contains 10 mg/kg each of vanadium, nickel, andiron. Combine the organometallic standard, dilution solventand, if necessary, mineral oil so that the oil content of thecalibration standard is 10 % (

32、m/m).9.5 Quality Control (QC) SamplesWeigh a portion of thewell-mixed QC sample into a container and add sufficientsolvent to achieve a sample concentration of 10 % (m/m).10. Preparation of Apparatus10.1 Consult Practice D7260 regarding the optimum opera-tion of any ICP-AES system.4Reagent Chemicals

33、, American 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 For

34、mulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.5Fluoroelastomer copolymer is manufactured as Viton, a trademark owned by E.I. duPont de Nemours.D5708 11210.2 Consult the manufacturers instructions for the opera-tion of the ICP instrument. This test method assumes that goodoperating

35、 procedures are followed. Design differences betweeninstruments make it impractical to specify required parameters.10.3 Assign the appropriate operating parameters to theinstrument taskfile so that the desired analytes can be deter-mined. Parameters include: (1) element, (2) analytical wave-length,

36、(3) background correction wavelengths (optional), (4)interelement correction factors (refer to 10.4), (5) integrationtime of 1 to 10 s, (6) two to five consecutive repeat integra-tions. Suggested wavelengths are listed in Table 1.10.4 Spectral InterferencesCheck all spectral interfer-ences expected

37、for the analytes. If interference corrections arenecessary, follow the manufacturers operating guide to de-velop and apply correction factors.10.4.1 Spectral interferences can usually be avoided byjudicious choice of analytical wavelengths. If spectral interfer-ences cannot be avoided, the necessary

38、 corrections should bemade using the computer software supplied by the instrumentmanufacturer or by using the empirical method described inTest Method D5185.10.5 Consult the instrument manufacturers instructions foroperating the instrument with organic solvents.10.6 During instrument warm-up, nebuli

39、ze the blank solu-tion. Inspect the torch for carbon build-up. When carbonbuild-up occurs, replace the torch and adjust the operatingconditions to correct the problem.10.6.1 Carbon build-up within the torch can be caused byimproperly adjusted argon flow rates, improper solution flowrates, and positi

40、oning the torch injector tube too close to theload coil. Carbon deposits can invalidate a calibration andextinguish the plasma.11. Calibration and Analysis11.1 Using the blank and working standard, perform atwo-point calibration at the beginning of the analysis of eachbatch of specimens. Additional

41、working standards can be used,if desired.11.2 Use the check standard to determine if the calibrationfor each analyte is accurate. When the result obtained on thecheck standard is not within 65 % of the expected concentra-tion for each analyte, take corrective action and repeat thecalibration.11.3 An

42、alyze the specimens in the same manner as thecalibration standards (that is, same integration time, plasmaconditions, and so forth). Calculate concentrations by multi-plying the concentration determined for the test specimensolution by the dilution factor. Calculation of concentrationscan be perform

43、ed manually or by computer when such afeature is available.11.4 When the measured intensities for the test specimensolution exceed the corresponding intensities for the workingstandard, either ensure that the calibration curve is linear to theconcentration of the element in the test specimen solutio

44、n ordilute the test specimen solution with the blank solution andreanalyze.11.5 Analyze the check standard after every fifth specimen.If any result is not within 5 % of the expected concentration,take corrective action, repeat the calibration, and reanalyze thespecimen solutions back to the previous

45、 acceptable checkstandard analysis.11.6 The use of spectral background correction is highlyrecommended, particularly when the test specimen solutionscontain low concentrations of the analytes (typically less than1 mg/kg). When concentrations are low, background changes,which can result from variabil

46、ity in the compositions of testspecimen solutions, can affect the accuracy of the analysis.Background correction minimizes errors due to variable back-ground intensities.TEST METHOD BICP AFTER ACID DECOMPOSITION OF SAMPLE12. Apparatus12.1 Refer to 7.1-7.4.12.2 Sample Decomposition Apparatus (optiona

47、l)Thisapparatus is shown in Fig. 1. It consists of a high-silica orborosilicate 400-mL beaker for the specimen, an air bath (Fig.2) that rests on a hot plate, and a 250-watt infrared lampsupported 1 in. above the air bath. A variable transformercontrols the voltage applied to the lamp.12.3 Glassware

48、, high-silica or borosilicate 400-mL beakers,volumetric flasks of various capacities, and pipettes of variousTABLE 1 Elements Determined and Suggested WavelengthsNOTEThese wavelengths are suggestions and do not represent allpossible choices.AElement Wavelength, nmIron 259.94, 238.20Nickel 231.60, 21

49、6.56Vanadium 292.40, 310.22AWinge, R. K., Fassel, V. A., Peterson, V. J., and Floyd, M. A., InductivelyCoupled Plasma Atomic Emission Spectroscopy: An Atlas of Spectral Information,Elsevier, NY, 1985. FIG. 1 Decomposition ApparatusD5708 113capacities. When determining concentrations below 1 mg/kg,all glassware must be thoroughly cleaned and rinsed withwater.12.4 Electric Muffle Furnace, capable of maintaining 525 625C and sufficiently large to accommodate 400-mL beakers.The capability of an oxygen bleed is advantageous andoptional.12.5 Steam Bath (opti