ASTM D7220-06
(Test Method)Standard Test Method for Sulfur in Automotive Fuels by Polarization X-ray Fluorescence Spectrometry
Standard Test Method for Sulfur in Automotive Fuels by Polarization X-ray Fluorescence Spectrometry
SIGNIFICANCE AND USE
This test method provides measurement of total sulfur in automotive fuels with a minimum of sample preparation. A typical analysis time is 200 to 300 s per sample.
The quality of automotive fuel can be related to the amount of sulfur present. Knowledge of sulfur concentration is necessary for processing purposes. There are also regulations promulgated in federal, state, and local agencies that restrict the amount of sulfur present in some fuel.
If this test method is applied to petroleum materials with matrices significantly different from the calibration materials specified in this test method, the cautions and recommendations in Section 6 should be observed when interpreting the results.
SCOPE
1.1 This test method specifies an energy-dispersive X-ray fluorescence (EDXRF) method for the determination of total sulfur in automotive fuels with a concentration range of 6 mg/kg to 50 mg/kg.
1.1.1 The pooled limit of quantitation of this test method as obtained by statistical analysis of inter laboratory test results is 6 mg/kg sulfur.
1.2 A fundamental assumption in this test method is that the standard and sample matrix is well matched. Matrix mismatch can be caused by C/H ratio differences between samples and standards or by the presence of other heteroatoms.
1.3 The values stated in SI units are to be regarded as the standard. The preferred concentration units are mg/kg sulfur.
1.4 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)
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Designation:D7220–06
Standard Test Method for
Sulfur in Automotive Fuels by Polarization X-ray
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Fluorescence Spectrometry
This standard is issued under the fixed designation D7220; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope ISO 4259 Determination and application of precision data
in relation to methods of test
1.1 This test method specifies an energy-dispersive X-ray
fluorescence (EDXRF) method for the determination of total
3. Terminology
sulfur in automotive fuels with a concentration range of 6
3.1 Definitions:
mg/kg to 50 mg/kg.
3.1.1 polarization X-ray fluorescence, n—typically a polar-
1.1.1 The pooled limit of quantitation of this test method as
ization EDXRF instrument is used. In difference to direct
obtained by statistical analysis of inter laboratory test results is
excitation EDXRF spectrometry, polarization X-ray fluores-
6 mg/kg sulfur.
cence uses polarized radiation for excitation. Combined with
1.2 Afundamental assumption in this test method is that the
Cartesian geometry (of excitation, sample and detection sys-
standard and sample matrix is well matched. Matrix mismatch
tem) this results in a significant improvement of the detection
can be caused by C/H ratio differences between samples and
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limit compared to direct excitation EDXRF.
standards or by the presence of other heteroatoms.
3.2 Abbreviations:
1.3 The values stated in SI units are to be regarded as the
3.2.1 DBS—actual mass of Di-n-butyl sulfide, g
standard. The preferred concentration units are mg/kg sulfur.
3.2.2 EDXRF—Energy dispersive X-ray spectrometry
1.4 This standard does not purport to address all of the
3.2.3 PTFE—Polytetrafluorethylene
safety concerns, if any, associated with its use. It is the
3.2.4 SDBS—mass % of sulfur in Di-n-butyl sulfide, typi-
responsibility of the user of this standard to establish appro-
cally 21.91%
priate safety and health practices and determine the applica-
3.2.5 SStd—mg/kg sulfur in the calibration standard
bility of regulatory limitations prior to use.
3.2.6 SStock—mg/kg of sulfur in the stock standard
3.2.7 STK—actual mass of stock standard, g
2. Referenced Documents
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2.1 ASTM Standards:
4. Summary of Test Method
D4057 Practice for Manual Sampling of Petroleum and
4.1 The sample is placed in the polarized X-ray beam, and
Petroleum Products
the peak area of the sulfur Ka line at 2.307 keV is measured.
D4177 Practice for Automatic Sampling of Petroleum and
The background spectrum, measured with a sulfur free white
Petroleum Products
oil or other matrix matching blank sample (see 8.4) is adapted
D6299 Practice for Applying Statistical Quality Assurance
to the measured spectrum using adjustment regions following
and Control Charting Techniques to Evaluate Analytical
the instrument manufacturer’s instructions and then subtracted
Measurement System Performance
from the measured spectrum. The resultant net counting rate is
E29 Practice for Using Significant Digits in Test Data to
then compared to a previously prepared calibration curve or
Determine Conformance with Specifications
equation to obtain the concentration of sulfur in mg/kg.
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2.2 ISO Standard:
(Warning—Exposure to excessive quantities of X-radiation is
injurious to health. The operator needs to take appropriate
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This test method is under the jurisdiction of ASTM Committee D02 on
actions to avoid exposing any part of their body, not only to
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
primary X-rays, but also to secondary or scattered radiation
D02.03 on Elemental Analysis.
that might be present. The X-ray spectrometer should be
Current edition approved Feb. 15, 2006. Published March 2006. DOI: 10.1520/
D7220-06.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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Standards volume information, refer to the standard’s Document Summary page on Wissmann, D., “Latest Improvements on Using Polarized X-Ray Excitation
the ASTM website. EDXRF for the Analysis of Low Sulfur Content in Automotive Fuel,” Journal of
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Available from International Organization for Standardization (ISO), 1, rue de ASTM International, Vol 2, Issue 9, Paper ID JAI12975, October 2005. Visit the
Varembé, Case postale 56 CH-1211 Geneva 20, Switzerland. ASTM website, www.astm.org, Books & Journals.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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