ASTM D5708-2012 red 5000 Standard Test Methods for Determination of Nickel Vanadium and Iron in Crude Oils and Residual Fuels by Inductively Coupled Plasma (ICP) Atomic Emission Sp.pdf

1、Designation: D5708 11D5708 12Standard 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 designatio

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

3、ination of nickel, vanadium, and iron in crude oils and residual fuels by inductivelycoupled plasma (ICP) atomic emission spectrometry. Two different test methods are presented.1.2 Test Method A (Sections 7-11 and 18-22)ICPis used to analyze a sample dissolved in an organic solvent. This test method

4、uses oil-soluble metals for calibration and does not purport to quantitatively determine or detect insoluble particulates.1.3 Test Method B (Sections 12-22) ICP is used to analyze a sample that is decomposed with acid.1.4 The concentration ranges covered by these test methods are determined by the s

5、ensitivity of the instruments, the amountof sample taken for analysis, and the dilution volume.Aspecific statement is given in 15.2. Typically, the low concentration limitsare a few tenths of a mg/kg. Precision data are provided for the concentration ranges specified in Section 21.1.5 The values sta

6、ted in SI units are to be regarded as standard. The values given in parentheses are for information only.1.6 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

7、 health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1548 Test Method for Vanadium in Heavy Fuel Oil1 (Withdrawn 1997)3D4057 Practice for Manual Sampling of Petroleum and Petroleum Pro

8、ductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD5185 Test Method for Determination of Additive Elements, Wear Metals, and Contaminants in Used Lubricating Oils andDetermination of Selected Elements in Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry

9、 (ICP-AES)D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD7260 Practice for Optimization, Calibration, and Validation of Inductively Coupled Plasma-Atomic Emission Spectrometry(ICP-AES) for Elemental Ana

10、lysis of Petroleum Products and Lubricants3. Summary of Test Method3.1 Test Method AApproximately 10 g of the sample are dissolved in an organic solvent (WarningCombustible. Vapor isharmful.) to give a specimen solution containing 10 % (m/m) of sample. The solution is nebulized into the plasma, and

11、theintensities of the emitted light at wavelengths characteristic of the analytes are measured sequentially or simultaneously. Theintensities are related to concentrations by the appropriate use of calibration data.1 These test methods are under the jurisdiction of ASTM Committee D02 on Petroleum Pr

12、oducts and Lubricants and is the direct responsibility of Subcommittee D02.03on Elemental Analysis.Current edition approved June 1, 2011Dec. 1, 2012. Published July 2011January 2013. Originally approved in 1995. Last previous edition approved in 20052011 asD570805.11. DOI: 10.1520/D5708-11.10.1520/D

13、5708-12.2 For referencedASTM standards, visit 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 The last approved version of this historical standa

14、rd is referenced on www.astm.org.This document 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 recomm

15、ends that users consult prior editions as 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

16、, West Conshohocken, PA 19428-2959. United States13.2 Test Method BOne to 20 g of sample are weighed into a beaker and decomposed with concentrated sulfuric acid(WarningPoison. Causes severe burns. Harmful or fatal if swallowed or inhaled.) by heating to dryness. Great care must be usedin this decom

17、position because the acid fumes are corrosive and the mixture is potentially flammable. The residual carbon is burnedoff by heating at 525C in a muffle furnace. The inorganic residue is digested with nitric acid(WarningPoison. Causes severeburns. Harmful or fatal if swallowed or inhaled.), evaporate

18、d to incipient dryness, dissolved in dilute nitric acid, and made up tovolume. The solution is nebulized into the plasma of an atomic emission spectrometer. The intensities of light emitted atcharacteristic wavelengths of the metals are measured sequentially or simultaneously. These intensities are

19、related toconcentrations by the appropriate use of calibration data.4. Significance and Use4.1 These test methods cover, in single procedures, the determination of Ni, V, and Fe in crude oils and residual oils. These testmethods complement Test Method D1548, which covers only the determination of va

20、nadium.4.2 When fuels are combusted, vanadium present in the fuel can form corrosive compounds. The value of crude oils can bedetermined, in part, by the concentrations of nickel, vanadium, and iron. Nickel and vanadium, present at trace levels in petroleumfractions, can deactivate catalysts during

21、processing. These test methods provide a means of determining the concentrations ofnickel, vanadium, and iron.5. Purity of Reagents5.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents conform to thespecifications of the Committee onAnal

22、ytical Reagents of theAmerican Chemical Society where such specifications are available.4Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use withoutlessening the accuracy of the determination.5.2 When determining metals at conc

23、entrations less than 1 mg/kg, use ultra-pure reagents.5.3 Purity of WaterUnless otherwise indicated, reference to water shall be understood to mean reagent water conforming toType II of Specification D1193.6. Sampling and Sample Handling6.1 The objective of sampling is to obtain a sample for testing

24、 purposes that is representative of the entire quantity. Thus, takesamples in accordance with the instructions in Practice D4057 or D4177. Do not fill the sample container more than two-thirdsfull.6.2 Prior to weighing, stir the sample and manually shake the sample container. If the sample does not

25、readily flow at roomtemperature, heat the sample in a drying oven at 80C or at another safe temperature.TEST METHOD AICP WITH AN ORGANIC SOLVENT SPECIMEN SOLUTION7. Apparatus7.1 Inductively Coupled Plasma Atomic Emission SpectrometerEither a sequential or simultaneous spectrometer, equippedwith a qu

26、artz torch and radio-frequency generator to form and sustain the plasma, is suitable.7.2 NebulizerThe use of a high-solids nebulizer is optional but strongly recommended. This type of nebulizer minimizes theprobability of clogging. A concentric glass nebulizer can also be used.7.3 Peristaltic PumpTh

27、is pump is required for non-aspirating nebulizers and optional for aspirating nebulizers. The pumpmust achieve a flow rate in the range of 0.5 to 3 mL/min. The pump tubing must be able to withstand at least a 6 h exposure tothe solvent. Fluoroelastomer copolymer tubing is recommended.57.4 Specimen S

28、olution Containers , Containers, glass or plastic vials or bottles with screw caps having a capacity of appropriatesize. One hundred millilitre glass bottles are satisfactory.8. Reagents8.1 Dilution SolventMixed xylenes, o-xylene, tetralin and mixed paraffin-aromatic solvents are satisfactory. Solve

29、nt purity canaffect analytical accuracy when the sample contains low concentrations (typically, a few mg/kg) of the analytes.8.2 Mineral OilA high-purity oil such as U.S.P. white oil.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggest

30、ions 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. (USPC), Rockville, MD.5 Fluoroelastomer copolymer is

31、 manufactured as Viton, a trademark owned by E. I. duPont de Nemours.D5708 1228.3 Organometallic StandardsPre-prepared multielement concentrates containing 100 mg/kg concentrations of each elementare satisfactory.8.4 Quality Control (QC) Samples, preferably are portions of one or more liquid petrole

32、um materials that are stable andrepresentative of the samples of interest. These QC samples can be used to check the validity of the testing process as describedin Section 19.9. Preparation of Standards and Specimens9.1 BlankPrepare a blank by diluting mineral oil with dilution solvent. The concentr

33、ation of mineral oil must be 10 % (m/m).Mix well.9.2 Check StandardUsing organometallic standards, mineral oil, and dilution solvent, prepare a check standard to containanalyte concentrations approximately the same as expected in the specimens. The concentration of oil in the check standard mustbe 1

34、0 % (m/m).9.3 Test SpecimenWeigh a portion of well-mixed sample into a container and add sufficient solvent to achieve a sampleconcentration of 10 % (m/m). Mix well.9.4 Working StandardPrepare an instrument calibration standard that contains 10 mg/kg each of vanadium, nickel, and iron.Combine the or

35、ganometallic standard, dilution solvent and, if necessary, mineral oil so that the oil content of the calibrationstandard is 10 % (m/m).9.5 Quality Control (QC) SamplesWeigh a portion of the well-mixed QC sample into a container and add sufficient solventto achieve a sample concentration of 10 % (m/

36、m).10. Preparation of Apparatus10.1 Consult Practice D7260 regarding the optimum operation of any ICP-AES system.10.2 Consult the manufacturers instructions for the operation of the ICP instrument. This test method assumes that goodoperating procedures are followed. Design differences between instru

37、ments make it impractical to specify required parameters.10.3 Assign the appropriate operating parameters to the instrument taskfile so that the desired analytes can be determined.Parameters include: (1) element, (2) analytical wavelength, (3) background correction wavelengths (optional), (4) intere

38、lementcorrection factors (refer to 10.4), (5) integration time of 1 to 10 s, (6 ) two to five consecutive repeat integrations. Suggestedwavelengths are listed in Table 1.10.4 Spectral InterferencesCheck all spectral interferences expected for the analytes. If interference corrections are necessary,f

39、ollow the manufacturers operating guide to develop and apply correction factors.10.4.1 Spectral interferences can usually be avoided by judicious choice of analytical wavelengths. If spectral interferencescannot be avoided, the necessary corrections should be made using the computer software supplie

40、d by the instrument manufactureror by using the empirical method described in Test Method D5185.10.5 Consult the instrument manufacturers instructions for operating the instrument with organic solvents.10.6 During instrument warm-up, nebulize the blank solution. Inspect the torch for carbon build-up

41、. When carbon build-upoccurs, replace the torch and adjust the operating conditions to correct the problem.10.6.1 Carbon build-up within the torch can be caused by improperly adjusted argon flow rates, improper solution flow rates,and positioning the torch injector tube too close to the load coil. C

42、arbon deposits can invalidate a calibration and extinguish theplasma.11. Calibration and Analysis11.1 Using the blank and working standard, perform a two-point calibration at the beginning of the analysis of each batch ofspecimens. Additional working standards can be used, if desired.TABLE 1 Element

43、s Determined and Suggested WavelengthsNOTE 1These wavelengths are suggestions and do not represent allpossible choices.AElement Wavelength, nmIron 259.94, 238.20Nickel 231.60, 216.56Vanadium 292.40, 310.22A Winge, R. K., Fassel, V.A., Peterson, V. J., and Floyd, M.A., Inductively CoupledPlasmaAtomic

44、 Emission Spectroscopy:AnAtlas of Spectral Information, Elsevier,NY, 1985.D5708 12311.2 Use the check standard to determine if the calibration for each analyte is accurate. When the result obtained on the checkstandard is not within 65 % of the expected concentration for each analyte, take correctiv

45、e action and repeat the calibration.11.3 Analyze the specimens in the same manner as the calibration standards (that is, same integration time, plasma conditions,and so forth). Calculate concentrations by multiplying the concentration determined for the test specimen solution by the dilutionfactor.

46、Calculation of concentrations can be performed manually or by computer when such a feature is available.11.4 When the measured intensities for the test specimen solution exceed the corresponding intensities for the working standard,either ensure that the calibration curve is linear to the concentrat

47、ion of the element in the test specimen solution or dilute the testspecimen solution with the blank solution and reanalyze.11.5 Analyze the check standard after every fifth specimen. If any result is not within 5 % of the expected concentration, takecorrective action, repeat the calibration, and rea

48、nalyze the specimen solutions back to the previous acceptable check standardanalysis.11.6 The use of spectral background correction is highly recommended, particularly when the test specimen solutions containlow concentrations of the analytes (typically less than 1 mg/kg). When concentrations are lo

49、w, background changes, which canresult from variability in the compositions of test specimen solutions, can affect the accuracy of the analysis. Backgroundcorrection minimizes errors due to variable background intensities.TEST METHOD BICPAFTER ACID DECOMPOSITION OF SAMPLE12. Apparatus12.1 Refer to 7.1-7.4.12.2 Sample Decomposition Apparatus (optional)This apparatus is shown in Fig. 1. It consists of a high-silica or borosilicate400-mL beaker for the specimen, an air bath (Fig. 2) that rests on a hot plate, and a 250-watt infrared lamp supported 1 in.