ASTM D7040-2004(2015) 9354 Standard Test Method for Determination of Low Levels of Phosphorus in ILSAC GF 4 and Similar Grade Engine Oils by Inductively Coupled Plasma Atomic Emiss.pdf

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1、Designation: D7040 04 (Reapproved 2015)Standard Test Method forDetermination of Low Levels of Phosphorus in ILSAC GF 4and Similar Grade Engine Oils by Inductively CoupledPlasma Atomic Emission Spectrometry1This standard is issued under the fixed designation D7040; the number immediately following th

2、e 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers

3、the quantitative determinationof phosphorus in unused lubricating oils, such as InternationalLubricant Standardization and Approval Committee (ILSAC)GF 4 and similar grade engine oils, by inductively coupledplasma atomic emission spectrometry.1.2 The precision statements are valid for dilutions in w

4、hichthe mass % sample in solvent is held constant in the range of1mass % to 5 mass % oil.1.3 The precision tables define the concentration rangescovered in the interlaboratory study (500 mgkg to800 mgkg). However, both lower and higher concentrationscan be determined by this test method. The low con

5、centrationlimits are dependent on the sensitivity of the ICP instrumentand the dilution factor. The high concentration limits aredetermined by the product of the maximum concentrationdefined by the linear calibration curve and the sample dilutionfactor.1.4 The values stated in SI units are to be reg

6、arded as thestandard. The values given in parentheses are for informationonly.1.5 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 deter

7、mine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD4927 Test Methods for Elemental Analysis of Lu

8、bricantand Additive ComponentsBarium, Calcium,Phosphorus, Sulfur, and Zinc by Wavelength-DispersiveX-Ray Fluorescence SpectroscopyD4951 Test Method for Determination ofAdditive Elementsin Lubricating Oils by Inductively Coupled PlasmaAtomic Emission SpectrometryD5185 Test Method for Multielement Det

9、ermination ofUsed and Unused Lubricating Oils and Base Oils byInductively Coupled Plasma Atomic Emission Spectrom-etry (ICP-AES)D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality Syst

10、em in Petroleum Productsand Lubricants Testing Laboratories3. Summary of Test Method3.1 A sample portion is weighed and diluted by mass withmixed xylenes or other solvent. An internal standard, which isrequired, is either weighed separately into the test solution or ispreviously combined with the di

11、lution solvent. Calibrationstandards are prepared similarly. The solutions are introducedto the ICP instrument by a peristaltic pump (required). Bycomparing emission intensity of phosphorus in the test speci-men with emission intensities measured with the calibrationstandards and by applying the app

12、ropriate internal standard andbackground corrections, the concentrations of phosphorus inthe sample is calculated.4. Significance and Use4.1 This test method usually requires several minutes persample. Other test methods which can be used for the deter-mination of phosphorus in lubricating oils incl

13、ude WDXRFTest Method D4927 and ICPAES Test Methods D4951 andD5185. However, this test method provides more preciseresults than Test Methods D4951 or D5185.4.2 Lubricating oils are typically blends of additivepackages, and their specifications are also determined, in part,1This test method is under t

14、he jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved April 1, 2015. Published June 2015. Originallyapproved in 2004. Last previous edition approved in 2010 as D704

15、0 04 (2010).DOI: 10.1520/D7040-04R15.2For 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.Copyright ASTM Internati

16、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1by elemental composition. This test method can be used todetermine if unused lubricating oils meet specifications withrespect to elemental composition.4.3 It is expected that GF 4 grade engine oils marketed int

17、he years 2004 to 2005 will have a maximum phosphorusconcentration level of 500 mgkg to 800 mgkg. These limitsare required to minimize poisoning of automotive emissioncontrol catalysts by volatile phosphorus species. It is antici-pated that the later grades of oils may have even lowerphosphorus level

18、s.5. Interferences5.1 SpectralThere are no known spectral interferencesbetween phosphorus and other elements covered by this testmethod when using the spectral lines 177.51 nm, 178.29 nm,185.94 nm, 213.62 nm, 214.91 nm, or 253.40 nm for phospho-rus.These wavelengths are only suggested and do not rep

19、resentall possible choices. Wavelengths below 190 nm require avacuum or inert gas purged optical path be used. However, ifspectral interferences exist because of other interfering ele-ments or selection of other spectral lines, correct for theinterference using the technique described in Test Method

20、D5185.5.2 Viscosity Index Improver EffectViscosity indeximprovers, which can be present in multi-grade lubricating oils,can bias the measurements.3However, the biases can bereduced to negligible proportion by using the specified solvent-to-sample dilution and an internal standard.6. Apparatus6.1 Ind

21、uctively-Coupled Plasma Atomic EmissionSpectrometerEither a sequential or simultaneous spectrom-eter is suitable, if equipped with a quartz ICP torch and r-fgenerator to form and sustain the plasma.6.2 Analytical Balance, capable of weighing to 0.001 g or0.0001 g, capacity of 150 g.6.3 Peristaltic P

22、ump (Required)A peristaltic pump isrequired to provide a constant flow of solution. The pumpingspeed shall be in the range 0.5 mLmin to 3 mLmin. Thepump tubing shall be able to withstand at least a 6 h exposureto the dilution solvent. Fluoroelastomer copolymer4tubing isrecommended.6.4 Solvent Dispen

23、ser (Optional)Asolvent dispenser cali-brated to deliver the required weight of diluent can beadvantageous. Ensure that solvent drip does not affect accu-racy.6.5 Specimen Solution Containers, of appropriate size, glassor polyolefin vials, or bottles with screw caps.6.6 Vortexer (Optional)Vortex the

24、sample plus diluentmixture until the sample is completely dissolved.6.7 Ultrasonic Homogenizer (Optional)A bath-type orprobe-type ultrasonic homogenizer can be used to homogenizethe test specimen.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless

25、 otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.57.2 Base Oil, U.S.P. white oil, or a lubricating base oil thatis free of analytes, having a viscosity at

26、 room temperature asclose as possible to that of the samples to be analyzed.7.3 Internal Standard (Required)An oil-soluble internalstandard element is required. The following internal standardswere successfully used in the interlaboratory study on preci-sion: Co (most common), Sc, and Y. Other appro

27、priate internalstandards may also be used.7.4 Organometallic StandardsMulti-element standards,containing known concentrations (approximately 0.1 mass %)of each element, can be prepared from the individual metalconcentrates. Refer to Practice D4307 for a procedure forpreparation of multi-component li

28、quid blends. When preparingmulti-element standards, be certain that proper mixing isachieved. Commercially available multi-element blends (withknown concentrations of each element at approximately 0.1mass %) are also satisfactory.7.4.1 It can be advantageous to select concentrations that aretypical

29、of unused oils. However, it is imperative that concen-trations are selected such that the emission intensities measuredwith the working standards can be measured precisely (that is,the emission intensities are significantly greater than back-ground) and that these standards represent the linear regi

30、on ofthe calibration curve. Frequently, the instrument manufacturerpublishes guidelines for determining linear range.7.4.2 Some commercially available organometallic stan-dards are prepared from metal sulfonates and, therefore,contain sulfur.7.4.3 Petroleum additives can also be used as organometal-

31、lic standards if their use does not adversely affect precision norintroduce significant bias.7.5 Dilution SolventMixed xylenes, o-xylene, and kero-sine were successfully used in the interlaboratory study onprecision.8. Internal Standardization (Required)8.1 The internal standard procedure requires t

32、hat every testsolution (sample and standard) have the same concentration (ora known concentration) of an internal standard element that isnot present in the original sample. The internal standard isusually combined with the dilution solvent. Internal standard3Bansal, J. G., and McElroy, F. C., SAE P

33、aper 932694, October 1993.Availablefrom Society ofAutomotive Engineers (SAE), 400 Commonwealth Dr., Warrendale,PA 15096-0001.4Fluoroelastomer copolymer is manufactured as Viton, a trademark owned by E.I. duPont de Nemours.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical

34、 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 Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockvill

35、e,MD.D7040 04 (2015)2compensation is typically handled in one of two different ways,summarized as follows:8.1.1 Calibration curves are based on the measured intensityof each analyte divided (that is, scaled) by the measuredintensity of the internal standard per unit internal standardelement concentr

36、ation. Concentrations for each analyte in thetest specimen solution are read directly from these calibrationcurves.8.1.2 For each analyte and the internal standard element,calibration curves are based on measured (unscaled) intensi-ties. Uncorrected concentrations for each analyte in the testspecime

37、n solution are read from these calibration curves.Corrected analyte concentrations are calculated by multiplyingthe uncorrected concentrations by a factor equal to the actualinternal standard concentration divided by the uncorrectedinternal standard concentration determined by analysis.8.2 Dissolve

38、the organometallic compound representing theinternal standard in dilution solvent and transfer to a dispensingvessel. The stability of this solution shall be monitored andprepared fresh (typically weekly) when the concentration of theinternal standard element changes significantly. The concen-tratio

39、n of internal standard element shall be at least 100 timesits detection limit.Aconcentration in the range of 10 mgkg to20 mgkg is typical.NOTE 1This test method specifies that the internal standard iscombined with the dilution solvent because this technique is common andefficient when preparing many

40、 samples. However, the internal standardcan be added separately from the dilution solvent as long as the internalstandard concentration is constant or accurately known.9. Sampling9.1 The objective of sampling is to obtain a test specimenthat is representative of the entire quantity. Thus, take labor

41、a-tory samples in accordance with the instructions in PracticeD4057. The specific sampling technique can affect the accu-racy of this test method.10. Preparation of Apparatus10.1 InstrumentDesign differences between instruments,ICP excitation sources, and different selected analytical wave-lengths f

42、or individual spectrometers make it impractical todetail the operating conditions. Consult the manufacturersinstructions for operating the instrument with organic solvents.Set up the instrument for use with the particular dilutionsolvent chosen.10.2 Peristaltic PumpInspect the pump tubing and replac

43、eit, if necessary, before starting each day. Verify the solutionuptake rate and adjust it to the desired rate.10.3 ICP Excitation SourceInitiate the plasma source atleast 30 min before performing an analysis. During thiswarm-up period, nebulize the dilution solvent. Inspect the torchfor carbon build

44、up during the warm-up period. If carbonbuildup occurs, replace the torch immediately and consult themanufacturers operating guide to take proper steps to remedythe situation.NOTE 2Carbon that accumulates on the tip of the torch injector tubecan be removed by using nebulizer gas that consists of appr

45、oximately 1 %oxygen in argon.10.3.1 Generally, carbon buildup can be minimized byincreasing the intermediate argon flow rate or lowering thetorch, or both, relative to the load coil.NOTE 3Some manufacturers recommend even longer warm-up peri-ods to minimize changes in the slopes of the calibration c

46、urves.10.4 Wavelength ProfilingPerform any wavelength profil-ing that is specified in the normal operation of the instrument.10.5 Operating ParametersAssign the appropriate oper-ating parameters to the instrument task file so that the desiredelements can be determined. Parameters to be included aree

47、lement, wavelength, background correction points (required),interelement correction factors (refer to 5.1), integration time,and internal standard compensation (required). Multiple inte-grations (typically three) are required for each measurement.Atypical integration time is 10 s.11. Preparation of

48、Test Specimens11.1 DiluentDiluent refers to the dilution solvent contain-ing the internal standard (refer to 8.2).11.2 Test specimen solutions are prepared in the same waythat calibration standards are prepared (refer to 12.2). Themass % oil in diluent shall be the same for calibrationstandards and

49、test specimen solutions.11.2.1 Lubricating Oil SpecimensWeigh appropriateamount of the test specimen to the nearest 0.001 g. The weightof the test specimen taken will vary depending upon the metalconcentration of the specimen. Dilute by mass with the diluent.Mix well.11.3 Record all weights and calculate dilution factors bydividing the sum of the weights of the diluent, sample, and baseoil (if any) by the weight of the sample.11.4 The user of this test method has the option of selectingthe dilution factor, that is, the relative amounts of sample anddi