ASTM D3525-93(2002)e1

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An American National Standard
e1
Designation:D3525–93 (Reapproved 2002)
Standard Test Method for
Gasoline Diluent in Used Gasoline Engine Oils by Gas
Chromatography
This standard is issued under the fixed designation D 3525; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Warning notes were editorially moved into the standard text in March 2003.
1. Scope Example:
normal decane n-C
1.1 This test method utilizes gas chromatography to deter- 10
iso-tetradecane i-C
mine the amount of dilution in used gasoline fuel engine oils.
1.2 This test method is limited to gas chromatographs
3. Summary of Test Method
equipped with flame ionization detector and programmable
3.1 Gas chromatographic techniques are used with the
oven.
sample, containing a known percentage of n-tetradecane as an
internal standard, to determine the weight percent of the
NOTE 1—The use of other detectors and instrumentation has been
reported. However, the precision statement applies only when the instru-
sample boiling below the boiling point of the internal standard.
mentation specified is employed.
4. Significance and Use
1.3 The applicability of this method to gelled used engine
4.1 Some fuel dilution of the engine oil may take place
oils has not been adequately investigated to ensure compliance
duringnormaloperation.However,excessivefueldilutionisof
with the indicated repeatability and reproducibility. Gelled oils
concern in terms of possible performance problems.
are defined as oils that develop structure on standing, but that
return to their original fluidity with light agitation.
5. Apparatus
1.4 The values stated in SI units are to be regarded as the
5.1 Gas Chromatograph—Any gas chromatograph may be
standard. Inch-pound units are provided for information only.
used that has the following performance characteristics:
1.5 This standard does not purport to address all of the
5.1.1 Detector—Only a flame detector can be used in this
safety concerns, if any, associated with its use. It is the
method. The detector must have sufficient sensitivity to detect
responsibility of the user of this standard to establish appro-
1.0 % n-tetradecane with a peak height of at least 40 % of full
priate safety and health practices and determine the applica-
scale on the recorder under the conditions prescribed in this
bility of regulatory limitations prior to use.
method, and without loss of resolution. The detector must be
2. Terminology
capable of operating continuously at a temperature equivalent
to the maximum column temperature employed, and it must be
2.1 Definitions of Terms Specific to This Standard:
connected to the column so as to avoid any cold spots. When
2.1.1 fuel dilution—the amount, expressed as a percentage,
operating at this sensitivity level, detector stability must be
of engine fuel found in engine lubricating oil. This may be the
such that the baseline drift of not more than 1 % per hour is
result of engine wear or improper performance.
obtained.
2.2 Abbreviations:
5.1.2 Column Temperature Programmer—The chromato-
2.2.1 A common abreviation of hydrocarbon compounds is
graph must be capable of temperature program operation over
to designate the number of carbon atoms in the compound. A
a range sufficient to establish a retention time of 0.25 min (15
prefix is used to indicate the carbon chain form, while a
s) for the initial peak and to elute the internal standard totally.
subscripted suffix denotes the number of carbon atoms.
For determination of fuel dilution the reproducibility of the
programming rate is not significant, although a retention time
This test method is under the jurisdiction of ASTM Committee D02 on
repeatability of 0.3 min (18 s) should be available.
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
5.1.3 Sample Inlet System—The sample inlet system must
D02.04.0H on Chromatographic Distribution Methods.
be capable of operating continuously at a temperature equiva-
Current edition approved Dec. 10, 2002. Published March 2003. Originally
approved in 1976. Last previous edition approved in 1997 as D 3525 – 93 (1997). lent to the maximum column temperature employed. The
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
D3525–93 (2002)
sample inlet system must be connected to the chromatograph 7. Preparation of Apparatus
column so as to avoid any cold spot.
7.1 Column Preparation—Any satisfactory method used in
5.2 Recorder—A recording potentiometer with a full-scale
the practice of gas chromatography that will produce a column
response time of1sor less can be used.
meetingtherequirementsof4.3maybeused.Thecolumnmust
be conditioned at the maximum operating temperature until
5.3 Column—Any column and conditions may be used,
baseline drift due to column bleeding has been reduced to less
provided, under the conditions of the test, separations are in
than 1 % per hour.
order of boiling points and the column resolution, R, is at least
3 and not more than 8. Since a stable baseline is an essential
NOTE 3—Difficulty in achieving the baseline drift requirement may
requirement of this method, electronic single column compen-
indicate injection port or column overloading from contamination. Re-
sation is required to compensate for column bleed, which
move and clean the injection port. Reassemble and increase the tempera-
cannot be eliminated completely by conditioning alone. ture of the injection port, column oven, and detector to the maximum
limits of the gas chromatographic column employed.
5.4 Means must be provided for measuring the accumulated
area under the chromatogram. This can be done by a computer 7.1.1 To test column resolution prepare a mixture of 1
volume % each of C and C normal paraffins in a suitable
or electronic integrator. The computer or integrator must have
14 16
solvent such as octane (Warning—C and C n-paraffins.
the capability of subtracting an area profile obtained in a blank
14 16
Helium, nitrogen, and argon are compressed gases under
run from the corresponding area profile obtained during a
pressure.) (Warning—n-octane. Combustible, vapor harmful.)
sample run.
Inject the same volume of this mixture as to be used in analysis
NOTE 2—Some commercially available gas chromatographs permit the
of samples and obtain the chromatogram by the procedure
storing of data as a baseline profile of a blank run (without sample
described below. Calculate the resolution, R, from the distance
injection). With such instruments, sample run data can be corrected for
between C and C normal paraffin peaks at the peak
14 16
baseline drift through subtraction of the internally stored baseline profile
maxima, d, and the width of the peaks at the baseline, Y and
data from the sample run profile data. With this feature, further baseline 1
Y , as follows:
correction need not be required.
R 5 @2~d 2 d !#/~Y 1 Y ! (1)
1 2 1 2
5.5 Flow Controllers—Control of baseline drift to not more
than 1 % of full scale per hour as covered in 5.1.1 will require
Resolution, R, using the above equation, must be at least 3
that the gas chromatograph be equipped with constant-flow
and not more than 8.
controllers.
7.2 Chromatograph and Related Equipment—Place in ser-
5.6 Sample Introduction Apparatus—The sample is intro- vice in accordance with
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