ASTM D6732-04
(Test Method)Standard Test Method for Determination of Copper in Jet Fuels by Graphite Furnace Atomic Absorption Spectrometry
Standard Test Method for Determination of Copper in Jet Fuels by Graphite Furnace Atomic Absorption Spectrometry
SIGNIFICANCE AND USE
At high temperatures aviation turbine fuels can oxidize and produce insoluble deposits that are detrimental to aircraft propulsion systems. Very low copper concentrations (in excess of 50 μg/kg) can significantly accelerate this thermal instability of aviation turbine fuel. Naval shipboard aviation fuel delivery systems contain copper-nickel piping, which can increase copper levels in the fuel. This test method may be used for quality checks of copper levels in aviation fuel samples taken on shipboard, in refineries, and at fuel storage depots.
SCOPE
1.1 This test method covers the determination of copper in jet fuels in the range of 5 to 100 g/kg using graphite furnace atomic absorption spectrometry. Copper contents above 100 g/kg may be determined by sample dilution with kerosine to bring the copper level into the aforementioned method range. When sample dilution is used, the precision statements do not apply.
1.2 The values stated in SI units are to be regarded as standard.
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.
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Standards Content (Sample)
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Designation: D6732 – 04
Standard Test Method for
Determination of Copper in Jet Fuels by Graphite Furnace
1
Atomic Absorption Spectrometry
This standard is issued under the fixed designation D6732; 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* 3.2.1 absorbance, A, n—the logarithm to the base 10 of the
ratio of the reciprocal of the transmittance, T:
1.1 This test method covers the determination of copper in
jet fuels in the range of 5 to 100 µg/kg using graphite furnace A 5 log ~1/T! 5 –log T (1)
10 10
atomic absorption spectrometry. Copper contents above 100
3.2.2 integrated absorbance, A, n—the integrated area
i
µg/kg may be determined by sample dilution with kerosine to
under the absorbance peak generated by the atomic absorption
bring the copper level into the aforementioned method range.
spectrometer.
When sample dilution is used, the precision statements do not
apply.
4. Summary of Test Method
1.2 The values stated in SI units are to be regarded as
4.1 The graphite furnace is aligned in the light path of the
standard.
atomic absorption spectrometer equipped with background
1.3 This standard does not purport to address all of the
correction. An aliquot (typically 10 µL) of the sample is
safety concerns, if any, associated with its use. It is the
pipetted onto a platform in the furnace. The furnace is heated
responsibility of the user of this standard to establish appro-
to low temperature to dry the sample completely without
priate safety and health practices and determine the applica-
spattering. The furnace is then heated to a moderate tempera-
bility of regulatory limitations prior to use.
ture to eliminate excess sample matrix. The furnace is further
heated very rapidly to a temperature high enough to volatilize
2. Referenced Documents
the analyte of interest. It is during this step that the amount of
2
2.1 ASTM Standards:
light absorbed by the copper atoms is measured by the
D4057 Practice for Manual Sampling of Petroleum and
spectrometer.
Petroleum Products
4.2 The light absorbed is measured over a specified period.
D4306 Practice for Aviation Fuel Sample Containers for
The integrated absorbance A produced by the copper in the
i
Tests Affected by Trace Contamination
samples is compared to a calibration curve constructed from
D6299 Practice for Applying Statistical Quality Assurance
measured A values for organo-metallic standards.
i
and Control Charting Techniques to Evaluate Analytical
Measurement System Performance 5. Significance and Use
5.1 At high temperatures aviation turbine fuels can oxidize
3. Terminology
and produce insoluble deposits that are detrimental to aircraft
3.1 Definitions:
propulsion systems. Very low copper concentrations (in excess
3.1.1 radiant power, P, n—the rate at which energy is
of 50 µg/kg) can significantly accelerate this thermal instability
transported in a beam of radiant energy.
of aviation turbine fuel. Naval shipboard aviation fuel delivery
3.1.2 transmittance, T, n—the ratio of the radiant power
systems contain copper-nickel piping, which can increase
transmitted by a material to the radiant power incident upon it.
copper levels in the fuel. This test method may be used for
3.2 Definitions of Terms Specific to This Standard:
quality checks of copper levels in aviation fuel samples taken
on shipboard, in refineries, and at fuel storage depots.
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This test method is under the jurisdiction of ASTM Committee D02 on
6. Interferences
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.03 on Elemental Analysis.
6.1 Interferences most commonly occur due to light that is
Current edition approved Nov. 1, 2004. Published November 2004. Originally
absorbed by species other than the atomic species of interest.
approved in 2001. Last previous edition approved in 2002 as D6732–02. DOI:
Generally, this is due to undissociated molecular particles from
10.1520/D6732-04.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
thesamplematrix.Thecharstepinthefurnaceprogramisused
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
to eliminate as much of the matrix as possible before the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D6732 – 04
atomization step. Spectrometers are equipped with backgroun
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