ASTM D7040-04(2020)
(Test Method)Standard Test Method for Determination of Low Levels of Phosphorus in ILSAC GF 4 and Similar Grade Engine Oils by Inductively Coupled Plasma Atomic Emission Spectrometry
Standard Test Method for Determination of Low Levels of Phosphorus in ILSAC GF 4 and Similar Grade Engine Oils by Inductively Coupled Plasma Atomic Emission Spectrometry
SIGNIFICANCE AND USE
4.1 This test method usually requires several minutes per sample. Other test methods which can be used for the determination of phosphorus in lubricating oils include WDXRF Test Method D4927 and ICPAES Test Methods D4951 and D5185. However, this test method provides more precise results than Test Methods D4951 or D5185.
4.2 Lubricating oils are typically blends of additive packages, and their specifications are also determined, in part, by elemental composition. This test method can be used to determine if unused lubricating oils meet specifications with respect to elemental composition.
4.3 It is expected that GF 4 grade engine oils marketed in the years 2004 to 2005 will have a maximum phosphorus concentration level of 500 mg/kg to 800 mg/kg. These limits are required to minimize poisoning of automotive emission control catalysts by volatile phosphorus species. It is anticipated that the later grades of oils may have even lower phosphorus levels.
SCOPE
1.1 This test method covers the quantitative determination of phosphorus in unused lubricating oils, such as International Lubricant Standardization and Approval Committee (ILSAC) GF 4 and similar grade engine oils, by inductively coupled plasma atomic emission spectrometry.
1.2 The precision statements are valid for dilutions in which the mass % sample in solvent is held constant in the range of 1 % to 5 % by mass oil.
1.3 The precision tables define the concentration ranges covered in the interlaboratory study (500 mg/kg to 800 mg/kg). However, both lower and higher concentrations can be determined by this test method. The low concentration limits are dependent on the sensitivity of the ICP instrument and the dilution factor. The high concentration limits are determined by the product of the maximum concentration defined by the linear calibration curve and the sample dilution factor.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7040 − 04 (Reapproved 2020)
Standard Test Method for
Determination of Low Levels of Phosphorus in ILSAC GF 4
and Similar Grade Engine Oils by Inductively Coupled
Plasma Atomic Emission Spectrometry
This standard is issued under the fixed designation D7040; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the quantitative determination
D4057Practice for Manual Sampling of Petroleum and
of phosphorus in unused lubricating oils, such as International
Petroleum Products
Lubricant Standardization and Approval Committee (ILSAC)
D4307Practice for Preparation of Liquid Blends for Use as
GF 4 and similar grade engine oils, by inductively coupled
Analytical Standards
plasma atomic emission spectrometry.
D4927Test Methods for Elemental Analysis of Lubricant
1.2 Theprecisionstatementsarevalidfordilutionsinwhich
and Additive Components—Barium, Calcium,
the mass% sample in solvent is held constant in the range of
Phosphorus, Sulfur, and Zinc by Wavelength-Dispersive
1% to 5% by mass oil.
X-Ray Fluorescence Spectroscopy
1.3 The precision tables define the concentration ranges D4951TestMethodforDeterminationofAdditiveElements
covered in the interlaboratory study (500 mg⁄kg to in Lubricating Oils by Inductively Coupled Plasma
800mg⁄kg). However, both lower and higher concentrations
Atomic Emission Spectrometry
can be determined by this test method. The low concentration D5185Test Method for Multielement Determination of
limits are dependent on the sensitivity of the ICP instrument
Used and Unused Lubricating Oils and Base Oils by
and the dilution factor. The high concentration limits are Inductively Coupled Plasma Atomic Emission Spectrom-
determined by the product of the maximum concentration
etry (ICP-AES)
defined by the linear calibration curve and the sample dilution D6299Practice for Applying Statistical Quality Assurance
factor.
and Control Charting Techniques to Evaluate Analytical
Measurement System Performance
1.4 The values stated in SI units are to be regarded as the
D6792Practice for Quality Management Systems in Petro-
standard. The values given in parentheses are for information
leum Products, Liquid Fuels, and Lubricants Testing
only.
Laboratories
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3. Summary of Test Method
responsibility of the user of this standard to establish appro-
3.1 A sample portion is weighed and diluted by mass with
priate safety, health, and environmental practices and deter-
mixed xylenes or other solvent.An internal standard, which is
mine the applicability of regulatory limitations prior to use.
required,iseitherweighedseparatelyintothetestsolutionoris
1.6 This international standard was developed in accor-
previously combined with the dilution solvent. Calibration
dance with internationally recognized principles on standard-
standards are prepared similarly. The solutions are introduced
ization established in the Decision on Principles for the
to the ICP instrument by a peristaltic pump (required). By
Development of International Standards, Guides and Recom-
comparing emission intensity of phosphorus in the test speci-
mendations issued by the World Trade Organization Technical
men with emission intensities measured with the calibration
Barriers to Trade (TBT) Committee.
standardsandbyapplyingtheappropriateinternalstandardand
background corrections, the concentrations of phosphorus in
the sample is calculated.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.03 on Elemental Analysis. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2020. Published June 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2004. Last previous edition approved in 2015 as D7040–04 (2015). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D7040-04R20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7040 − 04 (2020)
4. Significance and Use 6.4 Solvent Dispenser (Optional)—Asolventdispensercali-
brated to deliver the required weight of diluent can be
4.1 This test method usually requires several minutes per
advantageous. Ensure that solvent drip does not affect accu-
sample. Other test methods which can be used for the deter-
racy.
mination of phosphorus in lubricating oils include WDXRF
Test Method D4927 and ICPAES Test Methods D4951 and 6.5 Specimen Solution Containers,ofappropriatesize,glass
D5185. However, this test method provides more precise or polyolefin vials, or bottles with screw caps.
results than Test Methods D4951 or D5185.
6.6 Vortexer (Optional)—Vortex the sample plus diluent
4.2 Lubricating oils are typically blends of additive mixture until the sample is completely dissolved.
packages, and their specifications are also determined, in part,
6.7 Ultrasonic Homogenizer (Optional)—A bath-type or
by elemental composition. This test method can be used to
probe-type ultrasonic homogenizer can be used to homogenize
determine if unused lubricating oils meet specifications with
the test specimen.
respect to elemental composition.
4.3 It is expected that GF 4 grade engine oils marketed in
7. Reagents and Materials
the years 2004 to 2005 will have a maximum phosphorus
7.1 Purity of Reagents—Reagent grade chemicals shall be
concentration level of 500mg⁄kg to 800mg⁄kg. These limits
used in all tests. Unless otherwise indicated, it is intended that
are required to minimize poisoning of automotive emission
all reagents conform to the specifications of the Committee on
control catalysts by volatile phosphorus species. It is antici-
Analytical Reagents of theAmerican Chemical Society where
pated that the later grades of oils may have even lower
such specifications are available.
phosphorus levels.
7.2 Base Oil, U.S.P. white oil, or a lubricating base oil that
5. Interferences is free of analytes, having a viscosity at room temperature as
close as possible to that of the samples to be analyzed.
5.1 Spectral—There are no known spectral interferences
between phosphorus and other elements covered by this test 7.3 Internal Standard (Required)—An oil-soluble internal
method when using the spectral lines 177.51nm, 178.29nm,
standard element is required. The following internal standards
185.94nm, 213.62nm, 214.91nm, or 253.40nm for phospho- were successfully used in the interlaboratory study on preci-
rus.Thesewavelengthsareonlysuggestedanddonotrepresent
sion:Co(mostcommon),Sc,andY.Otherappropriateinternal
all possible choices. Wavelengths below 190nm require a standards may also be used.
vacuum or inert gas purged optical path be used. However, if
7.4 Organometallic Standards—Multi-element standards,
spectral interferences exist because of other interfering ele-
containing known concentrations (approximately 0.1% by
ments or selection of other spectral lines, correct for the
mass) of each element, can be prepared from the individual
interference using the technique described in Test Method
metalconcentrates.RefertoPracticeD4307foraprocedurefor
D5185.
preparationofmulti-componentliquidblends.Whenpreparing
5.2 Viscosity Index Improver Effect—Viscosity index
multi-element standards, be certain that proper mixing is
improvers,whichcanbepresentinmulti-gradelubricatingoils, achieved. Commercially available multi-element blends (with
can bias the measurements. However, the biases can be
known concentrations of each element at approximately 0.1%
reducedtonegligibleproportionbyusingthespecifiedsolvent- by mass) are also satisfactory.
to-sample dilution and an internal standard.
7.4.1 Itcanbeadvantageoustoselectconcentrationsthatare
typical of unused oils. However, it is imperative that concen-
6. Apparatus
trationsareselectedsuchthattheemissionintensitiesmeasured
with the working standards can be measured precisely (that is,
6.1 Inductively-Coupled Plasma Atomic Emission
Spectrometer—Either a sequential or simultaneous spectrom- the emission intensities are significantly greater than back-
ground) and that these standards represent the linear region of
eter is suitable, if equipped with a quartz ICP torch and r-f
generator to form and sustain the plasma. the calibration curve. Frequently, the instrument manufacturer
publishes guidelines for determining linear range.
6.2 Analytical Balance, capable of weighing to 0.001g or
7.4.2 Some commercially available organometallic stan-
0.0001g, capacity of 150g.
dards are prepared from metal sulfonates and, therefore,
6.3 Peristaltic Pump (Required)—A peristaltic pump is
contain sulfur.
required to provide a constant flow of solution. The pumping
7.4.3 Petroleum additives can also be used as organometal-
speed shall be in the range 0.5mL⁄min to 3mL⁄min. The
licstandardsiftheirusedoesnotadverselyaffectprecisionnor
pump tubing shall be able to withstand at least a 6h exposure
introduce significant bias.
to the dilution solvent. Fluoroelastomer copolymer tubing is
recommended.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Bansal, J. G., and McElroy, F. C., SAE Paper 932694, October 1993.Available Standard-Grade Reference Materials, American Chemical Society, Washington,
fromSocietyofAutomotiveEngineers(SAE),400CommonwealthDr.,Warrendale, DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
PA 15096-0001. Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
FluoroelastomercopolymerismanufacturedasViton,atrademarkownedbyE. U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
I. duPont de Nemours. copeial Convention, Inc. (USPC), Rockville, MD.
D7040 − 04 (2020)
7.5 Dilution Solvent—Mixed xylenes, o-xylene, and kero- 10.3 ICP Excitation Source—Initiate the plasma source at
sine were successfully used in the interlaboratory study on least 30 min before performing an analysis. During this
precision. warm-upperiod,nebulizethedilutionsolvent.Inspectthetorch
for carbon buildup during the warm-up period. If carbon
8. Internal Standardization (Required) buildup occurs, replace the torch immediately and consult the
manufacturer’s operating guide to take proper steps to remedy
8.1 The internal standard procedure requires that every test
the situation.
solution(sampleandstandard)havethesameconcentration(or
a known concentration) of an internal standard element that is
NOTE 2—Carbon that accumulates on the tip of the torch injector tube
not present in the original sample. The internal standard is canberemovedbyusingnebulizergasthatconsistsofapproximately1%
oxygen in argon.
usually combined with the dilution solvent. Internal standard
compensationistypicallyhandledinoneoftwodifferentways,
10.3.1 Generally, carbon buildup can be minimized by
summarized as follows:
increasing the intermediate argon flow rate or lowering the
8.1.1 Calibrationcurvesarebasedonthemeasuredintensity
torch, or both, relative to the load coil.
of each analyte divided (that is, scaled) by the measured
NOTE 3—Some manufacturers recommend even longer warm-up peri-
intensity of the internal standard per unit internal standard
ods to minimize changes in the slopes of the calibration curves.
element concentration. Concentrations for each analyte in the
test specimen solution are read directly from these calibration 10.4 Wavelength Profiling—Perform any wavelength profil-
curves. ing that is specified in the normal operation of the instrument.
8.1.2 For each analyte and the internal standard element,
10.5 Operating Parameters—Assign the appropriate oper-
calibration curves are based on measured (unscaled) intensi-
ating parameters to the instrument task file so that the desired
ties. Uncorrected concentrations for each analyte in the test
elements can be determined. Parameters to be included are
specimen solution are read from these calibration curves.
element, wavelength, background correction points (required),
Corrected analyte concentrations are calculated by multiplying
interelement correction factors (refer to 5.1), integration time,
the uncorrected concentrations by a factor equal to the actual
and internal standard compensation (required). Multiple inte-
internal standard concentration divided by the uncorrected
grations(typicallythree)arerequiredforeachmeasurement.A
internal standard concentration determined by analysis.
typical integration time is 10s.
8.2 Dissolve the organometallic compound representing the
internalstandardindilutionsolventandtransfertoadispensing
11. Preparation of Test Specimens
vessel. The stability of this solution shall be monitored and
11.1 Diluent—Diluent refers to the dilution solvent contain-
preparedfresh(typicallyweekly)whentheconcentrationofthe
ing the internal standard (refer to 8.2).
internal standard element changes significantly. The concen-
tration of internal standard element shall be at least 100 times
11.2 Test specimen solutions are prepared in the same way
its detection limit.Aconcentration in the range of 10mg⁄kg to
that calibration standards are prepared (refer to 12.2). The
20mg⁄kg is typical.
mass% oil in diluent shall be the same for calibration
NOTE 1—This test method specifies that the internal standard is
standards and test specimen solutions.
combinedwiththedilutionsolventbecausethistechniqueiscommonand
11.2.1 Lubricating Oil Specimens—Weigh appropriate
efficient when preparing many samples. However, the internal standard
amount of the test specimen to the nearest 0.001g.The weight
can be added separately from the dilution solvent as long as the internal
standard concentration is constant or accurately known. of the test specimen taken will vary depending upon the metal
concentrationofthespecimen.Dilutebymasswiththediluent.
9. Sampling
Mix well.
9.1 The objective of sampling is to obtain a test specimen
11.3 Record all weights and calculate dilution factors by
that is representative of the entire quantity. Thus, take labora-
dividingthesumoftheweightsofthediluent,sample,andbase
tory sam
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