1、Designation: D7040 04 (Reapproved 2010)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.This standard has been approved for
3、use by agencies of the Department of Defense.1. Scope1.1 This test method covers 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 atomi
4、c emission spectrometry.1.2 The precision statements are valid for dilutions in whichthe mass % sample in solvent is held constant in the range of1 to 5 mass % oil.1.3 The precision tables define the concentration rangescovered in the interlaboratory study (500 to 800 mg/kg).However, both lower and
5、higher concentrations can be deter-mined by this test method. The low concentration limits aredependent on the sensitivity of the ICP instrument and thedilution factor.The high concentration limits are determined bythe product of the maximum concentration defined by thelinear calibration curve and t
6、he sample dilution factor.1.4 The values stated in SI units are to be regarded 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
7、 standard to establish appro-priate safety and health practices and determine 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
8、Use asAnalytical StandardsD4927 Test Methods for Elemental Analysis of Lubricantand Additive ComponentsBarium, Calcium, Phospho-rus, Sulfur, and Zinc by Wavelength-Dispersive X-RayFluorescence SpectroscopyD4951 Test Method for Determination of Additive Ele-ments in Lubricating Oils by Inductively Co
9、upled PlasmaAtomic Emission SpectrometryD5185 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 for Applying
10、 Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories3. Summary of Test Method3.1 A sample portion is weighed and diluted by mass withmixed xylenes o
11、r other solvent. An internal standard, which isrequired, is either weighed separately into the test solution or ispreviously combined with the dilution solvent. Calibrationstandards are prepared similarly. The solutions are introducedto the ICP instrument by a peristaltic pump (required). Bycomparin
12、g emission intensity of phosphorus in the test speci-men with emission intensities measured with the calibrationstandards and by applying the appropriate internal standard andbackground corrections, the concentrations of phosphorus inthe sample is calculated.4. Significance and Use4.1 This test meth
13、od usually requires several minutes persample. Other test methods which can be used for the deter-mination of phosphorus in lubricating oils include WDXRFTest Method D4927 and ICPAES Test Methods D4951 and1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubr
14、icants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved May 1, 2010. Published May 2010. Originallyapproved in 2004. Last previous edition approved in 2004 as D704004. DOI:10.1520/D7040-04R10.2For referenced ASTM standards, visit the ASTM website,
15、 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D
16、5185. However, this test method provides more preciseresults than Test Methods D4951 or D5185.4.2 Lubricating oils are typically blends of additive pack-ages, and their specifications are also determined, in part, byelemental composition. This test method can be used todetermine if unused lubricatin
17、g oils meet specifications withrespect to elemental composition.4.3 It is expected that GF 4 grade engine oils marketed inthe years 2004-2005 will have a maximum phosphorus con-centration level of 500 to 800 mg/kg. These limits are requiredto minimize poisoning of automotive emission control catalys
18、tsby volatile phosphorus species. It is anticipated that the latergrades of oils may have even lower phosphorus levels.5. Interferences5.1 SpectralThere are no known spectral interferencesbetween phosphorus and other elements covered by this testmethod when using the spectral lines 177.51, 178.29, 1
19、85.94,213.62, 214.91, or 253.40 nm for phosphorus. These wave-lengths are only suggested and do not represent all possiblechoices. Wavelengths below 190 nm require a vacuum or inertgas purged optical path be used. However, if spectral interfer-ences exist because of other interfering elements or sel
20、ection ofother spectral lines, correct for the interference using thetechnique described in Test Method D5185.5.2 Viscosity Index Improver EffectViscosity index im-provers, which can be present in multi-grade lubricating oils,can bias the measurements.3However, the biases can bereduced to negligible
21、 proportion by using the specified solvent-to-sample dilution and an internal standard.6. Apparatus6.1 Inductively-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 pla
22、sma.6.2 Analytical Balance, capable of weighing to 0.001 g or0.0001 g, capacity of 150 g.6.3 Peristaltic Pump (Required)A peristaltic pump isrequired to provide a constant flow of solution. The pumpingspeed shall be in the range 0.5 to 3 mL/min. The pump tubingshall be able to withstand at least a 6
23、-h exposure to the dilutionsolvent. Fluoroelastomer copolymer4tubing is recommended.6.4 Solvent Dispenser (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 app
24、ropriate size, glassor polyolefin vials, or bottles with screw caps.6.6 Vortexer (Optional)Vortex the 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.
25、 Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless 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.
26、2 Base Oil, U.S.P. white oil, or a lubricating base oil thatis free of analytes, having a viscosity at 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
27、successfully used in the interlaboratory study on preci-sion: Co (most common), Sc, and Y. Other appropriate 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 indi
28、vidual metalconcentrates. Refer to Practice D4307 for a procedure forpreparation of multi-component liquid blends. When preparingmulti-element standards, be certain that proper mixing isachieved. Commercially available multi-element blends (withknown concentrations of each element at approximately 0
29、.1mass %) are also satisfactory.7.4.1 It can be advantageous to select concentrations that aretypical 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 inte
30、nsities are significantly greater than back-ground) and that these standards represent the linear region ofthe calibration curve. Frequently, the instrument manufacturerpublishes guidelines for determining linear range.7.4.2 Some commercially available organometallic stan-dards are prepared from met
31、al sulfonates and, therefore,contain sulfur.7.4.3 Petroleum additives can also be used as organometal-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
32、study onprecision.8. Internal Standardization (Required)8.1 The internal standard procedure requires that 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 is
33、usually combined with the dilution solvent. Internal standard3Bansal, J. G., and McElroy, F. C., SAE Paper 932694 , October 1993.Availablefrom Society ofAutomotive Engineers (SAE), 400 Commonwealth Dr., Warrendale,PA 15096-0001.4Fluoroelastomer copolymer is manufactured as Viton, a trademark owned b
34、y E.I. duPont de Nemours.5Reagent Chemicals, 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
35、 United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7040 04 (2010)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 i
36、s, scaled) by the measuredintensity of the internal standard per unit internal standardelement concentration. 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 ba
37、sed on measured (unscaled) intensi-ties. Uncorrected concentrations for each analyte in the testspecimen solution are read from these calibration curves.Corrected analyte concentrations are calculated by multiplyingthe uncorrected concentrations by a factor equal to the actualinternal standard conce
38、ntration divided by the uncorrectedinternal standard concentration determined by analysis.8.2 Dissolve 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
39、weekly) when the concentration of theinternal standard element changes significantly. The concen-tration of internal standard element shall be at least 100 timesits detection limit. A concentration in the range of 10 to 20mg/kg is typical.NOTE 1This test method specifies that the internal standard i
40、scombined with the dilution solvent because this technique is common andefficient when preparing many 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
41、 sampling is to obtain a test specimenthat is representative of the entire quantity. Thus, take labora-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 dif
42、ferences between instruments,ICP excitation sources, and different selected analytical wave-lengths for individual spectrometers make it impractical todetail the operating conditions. Consult the manufacturersinstructions for operating the instrument with organic solvents.Set up the instrument for u
43、se with the particular dilutionsolvent chosen.10.2 Peristaltic PumpInspect the pump tubing and re-place it, if necessary, before starting each day. Verify thesolution uptake rate and adjust it to the desired rate.10.3 ICP Excitation SourceInitiate the plasma source atleast 30 min before performing a
44、n analysis. During thiswarm-up period, nebulize the dilution solvent. Inspect the torchfor carbon buildup 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 accum
45、ulates on the tip of the torch injector tubecan be removed by using nebulizer gas that consists of approximately 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 manu
46、facturers recommend even longer warm-up peri-ods to minimize changes in the slopes of the calibration curves.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
47、 the instrument task file so that the desiredelements can be determined. Parameters to be included areelement, wavelength, background correction points (required),interelement correction factors (refer to 5.1), integration time,and internal standard compensation (required). Multiple inte-grations (t
48、ypically three) are required for each measurement.Atypical integration time is 10 s.11. Preparation of 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
49、 are prepared (refer to 12.2). Themass % oil in diluent shall be the same for calibrationstandards and 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
