ASTM D7040-04(2010)
(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
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.
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.
It is expected that GF 4 grade engine oils marketed in the years 2004-2005 will have a maximum phosphorus concentration level of 500 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 mass % oil.
1.3 The precision tables define the concentration ranges covered in the interlaboratory study (500 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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7040 − 04(Reapproved 2010)
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 D4307Practice for Preparation of Liquid Blends for Use as
Analytical Standards
1.1 This test method covers the quantitative determination
D4927Test Methods for Elemental Analysis of Lubricant
of phosphorus in unused lubricating oils, such as International
and Additive Components—Barium, Calcium,
Lubricant Standardization and Approval Committee (ILSAC)
Phosphorus, Sulfur, and Zinc by Wavelength-Dispersive
GF 4 and similar grade engine oils, by inductively coupled
X-Ray Fluorescence Spectroscopy
plasma atomic emission spectrometry.
D4951TestMethodforDeterminationofAdditiveElements
1.2 Theprecisionstatementsarevalidfordilutionsinwhich
in Lubricating Oils by Inductively Coupled Plasma
the mass% sample in solvent is held constant in the range of
Atomic Emission Spectrometry
1 to 5 mass% oil.
D5185Test Method for Multielement Determination of
1.3 The precision tables define the concentration ranges Used and Unused Lubricating Oils and Base Oils by
Inductively Coupled Plasma Atomic Emission Spectrom-
covered in the interlaboratory study (500 to 800 mg/kg).
However, both lower and higher concentrations can be deter- etry (ICP-AES)
D6299Practice for Applying Statistical Quality Assurance
mined by this test method. The low concentration limits are
dependent on the sensitivity of the ICP instrument and the and Control Charting Techniques to Evaluate Analytical
Measurement System Performance
dilutionfactor.Thehighconcentrationlimitsaredeterminedby
the product of the maximum concentration defined by the D6792Practice for Quality System in Petroleum Products
and Lubricants Testing Laboratories
linear calibration curve and the sample dilution factor.
1.4 The values stated in SI units are to be regarded as the
3. Summary of Test Method
standard. The values given in parentheses are for information
3.1 A sample portion is weighed and diluted by mass with
only.
mixed xylenes or other solvent.An internal standard, which is
1.5 This standard does not purport to address all of the
required,iseitherweighedseparatelyintothetestsolutionoris
safety concerns, if any, associated with its use. It is the
previously combined with the dilution solvent. Calibration
responsibility of the user of this standard to establish appro-
standards are prepared similarly. The solutions are introduced
priate safety and health practices and determine the applica-
to the ICP instrument by a peristaltic pump (required). By
bility of regulatory limitations prior to use.
comparing emission intensity of phosphorus in the test speci-
men with emission intensities measured with the calibration
2. Referenced Documents
standardsandbyapplyingtheappropriateinternalstandardand
2.1 ASTM Standards:
background corrections, the concentrations of phosphorus in
D4057Practice for Manual Sampling of Petroleum and
the sample is calculated.
Petroleum Products
4. Significance and Use
4.1 This test method usually requires several minutes per
This test method is under the jurisdiction of ASTM Committee D02 on
sample. Other test methods which can be used for the deter-
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
D02.03 on Elemental Analysis.
mination of phosphorus in lubricating oils include WDXRF
Current edition approved May 1, 2010. Published May 2010. Originally
Test Method D4927 and ICPAES Test Methods D4951 and
approved in 2004. Last previous edition approved in 2004 as D7040–04. DOI:
D5185. However, this test method provides more precise
10.1520/D7040-04R10.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or results than Test Methods D4951 or D5185.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4.2 Lubricating oils are typically blends of additive
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. packages, and their specifications are also determined, in part,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7040 − 04 (2010)
by elemental composition. This test method can be used to 7. Reagents and Materials
determine if unused lubricating oils meet specifications with
7.1 Purity of Reagents—Reagent grade chemicals shall be
respect to elemental composition.
used in all tests. Unless otherwise indicated, it is intended that
4.3 It is expected that GF 4 grade engine oils marketed in all reagents conform to the specifications of the Committee on
the years 2004-2005 will have a maximum phosphorus con- Analytical Reagents of theAmerican Chemical Society where
centrationlevelof500to800mg/kg.Theselimitsarerequired such specifications are available.
tominimizepoisoningofautomotiveemissioncontrolcatalysts
7.2 Base Oil, U.S.P. white oil, or a lubricating base oil that
by volatile phosphorus species. It is anticipated that the later
is free of analytes, having a viscosity at room temperature as
grades of oils may have even lower phosphorus levels.
close as possible to that of the samples to be analyzed.
7.3 Internal Standard (Required)—An oil-soluble internal
5. Interferences
standard element is required. The following internal standards
5.1 Spectral—There are no known spectral interferences
were successfully used in the interlaboratory study on preci-
between phosphorus and other elements covered by this test
sion:Co(mostcommon),Sc,andY.Otherappropriateinternal
method when using the spectral lines 177.51, 178.29, 185.94,
standards may also be used.
213.62, 214.91, or 253.40 nm for phosphorus. These wave-
7.4 Organometallic Standards—Multi-element standards,
lengths are only suggested and do not represent all possible
containing known concentrations (approximately 0.1 mass%)
choices.Wavelengths below 190 nm require a vacuum or inert
of each element, can be prepared from the individual metal
gas purged optical path be used. However, if spectral interfer-
concentrates. Refer to Practice D4307 for a procedure for
encesexistbecauseofotherinterferingelementsorselectionof
preparationofmulti-componentliquidblends.Whenpreparing
other spectral lines, correct for the interference using the
multi-element standards, be certain that proper mixing is
technique described in Test Method D5185.
achieved. Commercially available multi-element blends (with
5.2 Viscosity Index Improver Effect—Viscosity index
known concentrations of each element at approximately 0.1
improvers,whichcanbepresentinmulti-gradelubricatingoils,
mass%) are also satisfactory.
can bias the measurements. However, the biases can be
7.4.1 Itcanbeadvantageoustoselectconcentrationsthatare
reducedtonegligibleproportionbyusingthespecifiedsolvent-
typical of unused oils. However, it is imperative that concen-
to-sample dilution and an internal standard.
trationsareselectedsuchthattheemissionintensitiesmeasured
with the working standards can be measured precisely (that is,
6. Apparatus
the emission intensities are significantly greater than back-
6.1 Inductively-Coupled Plasma Atomic Emission
ground) and that these standards represent the linear region of
Spectrometer—Either a sequential or simultaneous spectrom-
the calibration curve. Frequently, the instrument manufacturer
eter is suitable, if equipped with a quartz ICP torch and r-f
publishes guidelines for determining linear range.
generator to form and sustain the plasma.
7.4.2 Some commercially available organometallic stan-
6.2 Analytical Balance, capable of weighing to 0.001 g or dards are prepared from metal sulfonates and, therefore,
0.0001 g, capacity of 150 g.
contain sulfur.
7.4.3 Petroleum additives can also be used as organometal-
6.3 Peristaltic Pump (Required)—A peristaltic pump is
licstandardsiftheirusedoesnotadverselyaffectprecisionnor
required to provide a constant flow of solution. The pumping
introduce significant bias.
speed shall be in the range 0.5 to 3 mL/min. The pump tubing
shallbeabletowithstandatleasta6-hexposuretothedilution
7.5 Dilution Solvent—Mixed xylenes, o-xylene, and kero-
solvent. Fluoroelastomer copolymer tubing is recommended. sine were successfully used in the interlaboratory study on
precision.
6.4 Solvent Dispenser (Optional)—Asolventdispensercali-
brated to deliver the required weight of diluent can be
8. Internal Standardization (Required)
advantageous. Ensure that solvent drip does not affect accu-
8.1 The internal standard procedure requires that every test
racy.
solution(sampleandstandard)havethesameconcentration(or
6.5 Specimen Solution Containers,ofappropriatesize,glass
a known concentration) of an internal standard element that is
or polyolefin vials, or bottles with screw caps.
not present in the original sample. The internal standard is
6.6 Vortexer (Optional)—Vortex the sample plus diluent usually combined with the dilution solvent. Internal standard
mixture until the sample is completely dissolved. compensationistypicallyhandledinoneoftwodifferentways,
summarized as follows:
6.7 Ultrasonic Homogenizer (Optional)—A bath-type or
8.1.1 Calibrationcurvesarebasedonthemeasuredintensity
probe-type ultrasonic homogenizer can be used to homogenize
of each analyte divided (that is, scaled) by the measured
the test specimen.
Reagent Chemicals, American Chemical Society Specifications, American
Bansal,J.G.,andMcElroy,F.C., SAE Paper 932694,October1993.Available Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
fromSocietyofAutomotiveEngineers(SAE),400CommonwealthDr.,Warrendale, listed by the American Chemical Society, see Annual Standards for Laboratory
PA 15096-0001. Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
FluoroelastomercopolymerismanufacturedasViton,atrademarkownedbyE. and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
I. duPont de Nemours. MD.
D7040 − 04 (2010)
ods to minimize changes in the slopes of the calibration curves.
intensity of the internal standard per unit internal standard
element concentration. Concentrations for each analyte in the
10.4 Wavelength Profiling—Perform any wavelength profil-
test specimen solution are read directly from these calibration
ing that is specified in the normal operation of the instrument.
curves.
10.5 Operating Parameters—Assign the appropriate oper-
8.1.2 For each analyte and the internal standard element,
ating parameters to the instrument task file so that the desired
calibration curves are based on measured (unscaled) intensi-
elements can be determined. Parameters to be included are
ties. Uncorrected concentrations for each analyte in the test
element, wavelength, background correction points (required),
specimen solution are read from these calibration curves.
interelement correction factors (refer to 5.1), integration time,
Corrected analyte concentrations are calculated by multiplying
and internal standard compensation (required). Multiple inte-
the uncorrected concentrations by a factor equal to the actual
grations(typicallythree)arerequiredforeachmeasurement.A
internal standard concentration divided by the uncorrected
typical integration time is 10 s.
internal standard concentration determined by analysis.
8.2 Dissolve the organometallic compound representing the
11. Preparation of Test Specimens
internalstandardindilutionsolventandtransfertoadispensing
11.1 Diluent—Diluent refers to the dilution solvent contain-
vessel. The stability of this solution shall be monitored and
ing the internal standard (refer to 8.2).
preparedfresh(typicallyweekly)whentheconcentrationofthe
internal standard element changes significantly. The concen- 11.2 Test specimen solutions are prepared in the same way
tration of internal standard element shall be at least 100 times
that calibration standards are prepared (refer to 12.2). The
its detection limit. A concentration in the range of 10 to 20 mass% oil in diluent shall be the same for calibration
mg/kg is typical.
standards and test specimen solutions.
NOTE 1—This test method specifies that the internal standard is
11.2.1 Lubricating Oil Specimens—Weigh appropriate
combinedwiththedilutionsolventbecausethistechniqueiscommonand
amountofthetestspecimentothenearest0.001g.Theweight
efficient when preparing many samples. However, the internal standard
of the test specimen taken will vary depending upon the metal
can be added separately from the dilution solvent as long as the internal
concentrationofthespecimen.Dilutebymasswiththediluent.
standard concentration is constant or accurately known.
Mix well.
9. Sampling
11.3 Record all weights and calculate dilution factors by
9.1 The objective of sampling is to obtain a test specimen
dividingthesumoftheweightsofthediluent,sample,andbase
that is representative of the entire quantity. Thus, take labora-
oil (if any) by the weight of the sample.
tory samples in accordance with the instructions in Practice
11.4 Theuserofthistestmethodhastheoptionofselecting
D4057. The specific sampling technique can affect the accu-
the dilution factor, that is, the relative amounts of sample and
racy of this test method.
diluent.However,themass%sampleindiluent(forcalibration
10. Preparation of Apparatus
standardsandtestspecimens)shallbeconstantthroughoutthis
test method, and the mass% sample in diluent shall be in the
10.1 Instrument—Design differences between instruments,
range of 1 to 5 mass%.
ICPexcitation sources, and different selected analytical wave-
11.4.1 All references to dilute and diluting in this test
lengths for individual spectrometers make it impractical to
method refer to the user-selected dilution.
detail the operating conditions. Consult the manufacturer’s
instructionsforoperatingtheinstrumentwithorganicsolvents.
11.5 Blank—Prepare a blank by diluting the base oil or
Set up the instrument for use with the particular dilution
white oil with the diluent.
solvent chosen.
11.6 Working Standards—Weigh to the nearest 0.001 g,
10.2 Peristaltic Pump—Inspectthepumptubingandreplace
approximately1to3gofeachmulti-elementstandard(referto
it, if necessary, before starting each day. Verify the solution
7.4) into separate bottles. Dilute by mass with the diluent.
uptake rate and adjust it to the desired rat
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