ASTM D5863-2000a(2005) Standard Test Methods for Determination of Nickel Vanadium Iron and Sodium in Crude Oils and Residual Fuels by Flame Atomic Absorption Spectrometry《火焰原子吸收分光光.pdf

1、Designation: D 5863 00a (Reapproved 2005)An American National StandardStandard Test Methods forDetermination of Nickel, Vanadium, Iron, and Sodium inCrude Oils and Residual Fuels by Flame Atomic AbsorptionSpectrometry1This standard is issued under the fixed designation D 5863; the number immediately

2、 following the designation 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 These test

3、 methods cover the determination of nickel,vanadium, iron, and sodium in crude oils and residual fuels byflame atomic absorption spectrometry (AAS). Two differenttest methods are presented.1.2 Test Method A, Sections 713Flame AAS is used toanalyze a sample that is decomposed with acid for thedetermi

4、nation of total Ni, V, and Fe.1.3 Test Method B, Sections 1419Flame AAS is used toanalyze a sample diluted with an organic solvent for thedetermination of Ni, V, and Na. This test method uses oil-soluble metals for calibration to determine dissolved metalsand does not purport to quantitatively deter

5、mine nor detectinsoluble particulates. Hence, this test method may underesti-mate the metal content, especially sodium, present as inorganicsodium salts.1.4 The concentration ranges covered by these test methodsare determined by the sensitivity of the instruments, theamount of sample taken for analy

6、sis, and the dilution volume.A specific statement is given in Note 1.1.5 For each element, each test method has its own uniqueprecision. The user can select the appropriate test method basedon the precision required for the specific analysis.1.6 The values stated in SI units are to be regarded as th

7、estandard. The values given in parentheses are for informationonly.1.7 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 practices and determine the ap

8、plica-bility of regulatory limitations prior to use. Specific warningstatements are given in 7.1, 8.2, 8.5, 10.2, 10.4, and 15.1.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for

9、Automatic Sampling of Petroleum andPetroleum ProductsD 6299 Practice for Applying Statistical Quality AssuranceTechniques to Evaluate Analytical Measurement SystemPerformance3. Summary of Test Method3.1 Test Method AOne to twenty grams of sample areweighed into a beaker and decomposed with concentra

10、tedsulfuric acid by heating to dryness. The residual carbon isburned off by heating at 525C in a muffle furnace. Theinorganic residue is digested in dilute nitric acid, evaporated toincipient dryness, dissolved in dilute nitric and made up tovolume with dilute nitric acid. Interference suppressant i

11、sadded to the dilute nitric acid solution. The solution isnebulized into the flame of an atomic absorption spectrometer.A nitrous oxide/acetylene flame is used for vanadium and anair/acetylene flame is used for nickel and iron. The instrumentis calibrated with matrix-matched standard solutions. Them

12、easured absorption intensities are related to concentrations bythe appropriate use of calibration data.3.2 Test Method BSample is diluted with an organicsolvent to give a test solution containing either 5 % (m/m) or20 % (m/m) sample. The recommended sample concentrationis dependent on the concentrat

13、ions of the analytes in thesample. For the determination of vanadium, interference sup-pressant is added to the test solution. The test solution isnebulized into the flame of an atomic absorption spectrometer.1These test methods are under the jurisdiction of ASTM Committee D02 onPetroleum Products a

14、nd Lubricants and are the direct responsibility of Subcommit-tee D02.03 on Elemental Analysis.Current edition approved May 1, 2005. Published June 2005. Originallyapproved in 1995. Last previous edition approved in 2000 as D 586300a.2For referenced ASTM standards, visit the ASTM website, www.astm.or

15、g, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.A nitrous oxi

16、de/acetylene flame is used for vanadium and anair/acetylene flame is used for nickel and sodium. The mea-sured absorption intensities are related to concentrations by theappropriate use of calibration data.4. Significance and Use4.1 When fuels are combusted, metals present in the fuelscan form low m

17、elting compounds that are corrosive to metalparts. Metals present at trace levels in petroleum can deactivatecatalysts during processing. These test methods provide ameans of quantitatively determining the concentrations ofvanadium, nickel, iron, and sodium. Thus, these test methodscan be used to ai

18、d in determining the quality and value of thecrude oil and residual oil.5. Purity of Reagents5.1 Reagent grade chemicals shall be used for all tests.Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemic

19、al Society where suchspecifications are available.3Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.5.2 When determining metals at concentrations less than 1mg/kg, use ultra

20、-pure grade reagents.5.3 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Type II of Specification D 1193.6. Sampling and Sample Handling6.1 The objective of sampling is to obtain a sample fortesting purposes that is representative o

21、f the entire quantity.Only representative samples obtained as specified in PracticesD 4057 and D 4177 shall be used. Do not fill the samplecontainer more than two-thirds full6.2 Prior to weighing, stir the sample and then shake thesample in its container. If the sample does not readily flow atroom t

22、emperature, heat the sample to a sufficiently high andsafe temperature to ensure adequate fluidity.TEST METHOD AFLAME ATOMIC ABSORPTIONAFTER ACID DECOMPOSITION OF THE SAMPLE7. Apparatus7.1 Atomic Absorption Spectrometer, complete instrumentwith hollow cathode lamps and burners with gas supplies tosu

23、pport air-acetylene and nitrous oxide-acetylene flames.(WarningHazardous. Potentially toxic and explosive. Referto the manufacturers instrument manual for associated safetyhazards.)7.2 Sample Decomposition Apparatus (optional)This ap-paratus is described in Fig. 1. It consists of a borosilicate glas

24、s400-mL beaker for the test solution, an air bath (Fig. 2) thatrests on a hot plate and a 250 W infrared lamp supported 2.5cm above the air bath. A variable transformer controls thevoltage applied to the lamp.7.3 GlasswareBorosilicate glass 400-mL beakers, volu-metric flasks of various capacities an

25、d pipettes of variouscapacities. When determining concentrations below 1 mg/kg,all glassware must be thoroughly cleaned (or soaked overnight)with 5 % HNO3and rinsed five times with water.7.4 Electric Muffle Furnace, capable of maintaining 525 625C and sufficiently large to accommodate 400-mL beakers

26、.The capability of an oxygen bleed is advantageous andoptional.7.5 Steam Bath.7.6 Temperature Controlled Hot Plate, (optional).7.7 Drying Oven, (optional), explosion-proof, if used to heatcrude oils to obtain fluidity.8. Reagents8.1 Aqueous Standard SolutionsIndividual aqueous stan-dards with 1000 m

27、g/kg concentrations of vanadium, nickel,and iron, purchased or prepared in acid matrix to ensurestability.8.2 Nitric AcidConcentrated nitric acid, HNO3.(WarningPoison, oxidizer. Causes severe burns. Harmful orfatal if swallowed or inhaled.)8.3 Nitric Acid 50 % (V/V)Carefully add, with stirring,one v

28、olume of concentrated nitric acid to one volume of water.8.4 Dilute Nitric Acid, 5 % (V/V)Carefully add, withstirring, one volume of concentrated nitric acid to 19 volumesof water.8.5 Sulfuric AcidConcentrated sulfuric acid, H2SO4.(WarningPoison, oxidizer. Causes severe burns. Harmful orfatal if swa

29、llowed or inhaled.)3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the Unite

30、d States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Decomposition ApparatusD 5863 00a (2005)28.6 Aluminum Nitrate, Al(NO3)39HOH.8.7 Potassium Nitrate, KNO3.9. Preparation of Standards9.1 Multi-Element StandardUsing the aqueous standardsolution

31、s, prepare a multi-element standard containing 100mg/kg each of vanadium, nickel, and iron. Standards should beprepared to ensure accuracy and stability and should be storedin clean containers to safeguard against physical degradation.9.2 Working StandardsPrepare at least two working stan-dards to c

32、over the concentration ranges specified in Table 1.For vanadium, add the specified interference suppressant. Eachworking standard must contain 5 % (V/V) nitric acid. Stan-dards should be prepared to ensure accuracy and stability andshould be stored in clean containers to safeguard againstphysical de

33、gradation.9.3 Standard Blank, the standard blank contains 5 % (V/V)nitric acid and any interference suppressant specified in Table1.9.4 Check StandardPrepare a calibration check standardin the same way as the working standards and at analyteconcentrations that are typical of the specimens being ana-

34、lyzed.10. Preparation of Test Solutions10.1 Into a beaker, weigh an amount of sample estimated tocontain between 0.0025 and 0.12 mg of each metal to bedetermined. A typical mass is 10 g. Add 0.5 mL of H2SO4foreach gram of sample.NOTE 1If it is desired to extend the lower concentration limits of thet

35、est method, it is recommended that the decomposition be done in 10-gincrements up to a maximum of 100 g. It is not necessary to destroy all theorganic matter each time before adding additional amounts of the sampleand acid. When it is desired to determine higher concentrations, reduce thesample size

36、 accordingly.10.2 At the same time prepare reagent blanks using thesame amount of sulfuric acid as used for sample decomposi-tion. Reagent blanks should be carried through the sameprocedure as the samples. (WarningReagent blanks arecritical when determining concentrations below 1 mg/kg. Tosimplify t

37、he analysis, use the same volume of acid and thesame dilutions as used for the samples. For example, if 20 g ofsample is being decomposed, use 10 mL of sulfuric acid for thereagent blank.)10.3 The use of the air bath apparatus (Fig. 2) is optional.Place the beaker in the air bath, which is located i

38、n the hood.The hot plate is off at this time. Heat gently from the top withthe infrared lamp (Fig. 1) while stirring the test solution with aglass rod. As decomposition proceeds (indicated by a frothingand foaming), control the heat of the infrared lamp to maintainsteady evolution of fumes. Give con

39、stant attention to eachsample mixture until all risk of spattering and foaming is past.Then, gradually increase the temperature of both the hot plateand lamp until the sample is reduced to a carbonaceous ash.10.4 If the air bath apparatus is not used, heat the sampleand acid on a temperature control

40、led hot plate. As described in10.3, monitor the decomposition reaction and adjust thetemperature of the hot plate accordingly. (WarningHotfuming concentrated sulfuric acid is very corrosive and astrong oxidizing acid. The analyst should work in a well-ventilated hood and wear rubber gloves and a sui

41、table faceshield to protect against spattering acid.)10.5 Place the sample in the muffle furnace maintained at525 6 25C. Optionally, introduce a gentle stream of oxygeninto the furnace to expedite oxidation. Continue to heat untilthe carbon is completely removed.10.6 Dissolve the inorganic residue b

42、y washing down thewall of the beaker with about 10 mL of the 1 + 1 HNO3. Digeston a steam bath for 15 to 30 min. Transfer to a hot plate andgently evaporate to incipient dryness.10.7 Wash down the wall of the beaker with about 10 mL ofdilute nitric acid (5 % V/V). Digest on the steam bath until allN

43、oteAll parts 16 gage (1.5 mm, 0.060 in.) aluminum. All dimensions are ininches.Metric Equivalentsin. mm in. mm1 25.4 378 98.4112 38.1 5 1272 50.8 612 165.13116 77.8 . .FIG. 2 Air BathTABLE 1 AAS Conditions for the Determination of Vanadium,Nickel, and Iron Following Acid Sample DecompositionElementW

44、avelength,nmConcentrationRange, g/mLInterferenceSuppressantFlameVanadium 318.4 0.520 250 g/mL Al,Al(NO3)3in 5 %(V/V)HNO3N2O-C2H2Nickel 232.0 0.520 None Air-C2H2Iron 248.3 3.010 None Air-C2H2D 5863 00a (2005)3salts are dissolved. Allow to cool. Transfer quantitatively to avolumetric flask of suitable

45、 volume and make up to volumewith dilute nitric acid. This is the test solution.10.8 Pipette aliquots of the test solution into two separatevolumetric flasks. Retain one flask for the determination ofnickel and iron. To the other flask add aluminum interferencesuppressant for vanadium determination

46、(refer to Table 1) anddilute up to mark with dilute nitric acid (5 % V/V). Similarly,prepare a reagent blank solution for vanadium analysis.11. Preparation of Apparatus11.1 Consult the manufacturers instructions for the opera-tion of the atomic absorption spectrometer. This test methodassumes that g

47、ood operating procedures are followed. Designdifferences between spectrometers make it impractical toexactly specify required instrument settings.11.2 Set up the instrument to determine each analyte se-quentially.12. Calibration and Analysis12.1 For each analyte in turn, perform the following opera-

48、tion:12.2 Nebulize the appropriate blank standard and zero theinstrument.12.3 Nebulize the working standards, determine the absor-bance and construct a calibration curve of absorbance versusanalyte concentration utilizing the instruments concentrationmode if available, otherwise plot these values.12

49、.4 Use the check standard to determine if the calibrationfor each analyte is accurate. If the results obtained on the checkstandard are not within 65 % of the expected concentration foreach analyte, take corrective action and repeat the calibration.12.5 Nebulize the test solutions and measure and record theabsorbance. If appropriate, blank correct this absorbance bysubtracting the reagent blank absorbance.12.6 After measuring absorbances for a test solution, checkthe blank standard. If this does not read zero, check the system,and then repeat