ASTM D6810-07
(Test Method)Standard Test Method for Measurement of Hindered Phenolic Antioxidant Content in Non-Zinc Turbine Oils by Linear Sweep Voltammetry
Standard Test Method for Measurement of Hindered Phenolic Antioxidant Content in Non-Zinc Turbine Oils by Linear Sweep Voltammetry
SCOPE
1.1 This test method covers the voltammetric determination of hindered phenol antioxidants in new or in-service non-zinc turbine oils in concentrations from 0.0075 weight % up to concentrations found in new oils by measuring the amount of current flow at a specified voltage in the produced voltammogram.
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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Designation: D6810 − 07
StandardTest Method for
Measurement of Hindered Phenolic Antioxidant Content in
1
Non-Zinc Turbine Oils by Linear Sweep Voltammetry
This standard is issued under the fixed designation D6810; 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 shaken, the hindered phenol antioxidants and other solution
soluble oil components present in the sample are extracted into
1.1 This test method covers the voltammetric determination
the solution and the remaining droplets suspended in the
of hindered phenol antioxidants in new or in-service non-zinc
solution are agglomerated by the sand. The sand/droplet
turbine oils in concentrations from 0.0075 weight % up to
suspension is allowed to settle out and the hindered phenol
concentrations found in new oils by measuring the amount of
antioxidants dissolved in the solution are quantified by volta-
current flow at a specified voltage in the produced voltammo-
mmetric analysis. The results are calculated and reported as
gram.
weight percent of antioxidant or as millimoles (mmol) of
1.2 This standard does not purport to address all of the
antioxidant per litre of sample for prepared and fresh oils and
safety concerns, if any, associated with its use. It is the
as a percent remaining antioxidant for used oils.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 3.2 Voltammetric analysis is a technique that applies
bility of regulatory limitations prior to use.
electro-analytic methods when a sample to be analyzed is
mixed with an electrolyte and a solvent and placed within an
2. Referenced Documents
electrolytic cell. Data is obtained by measuring the current
2
passing through the cell as a function of the potential applied,
2.1 ASTM Standards:
and test results are based upon current, voltage and time
D1193 Specification for Reagent Water
relationships at the cell electrodes. The cell consists of a fluid
D4057 Practice for Manual Sampling of Petroleum and
container into which is mounted a small, easily polarized
Petroleum Products
working electrode, and a large nonpolarizable reference elec-
D4378 Practice for In-Service Monitoring of Mineral Tur-
trode.Thereferenceelectrodeshouldbemassiverelativetothe
bine Oils for Steam and Gas Turbines
working electrode so that its behavior remains essentially
D6224 PracticeforIn-ServiceMonitoringofLubricatingOil
for Auxiliary Power Plant Equipment constant with the passage of small current; that is, it remains
unpolarized during the analysis period. Additional electrodes,
D6447 Test Method for Hydroperoxide Number of Aviation
Turbine Fuels by Voltammetric Analysis auxiliary electrodes, can be added to the electrode system to
eliminate the effects of resistive drop for high resistance
D6971 Test Method for Measurement of Hindered Phenolic
and Aromatic Amine Antioxidant Content in Non-zinc solutions. In performing a voltammetric analysis, the potential
across the electrodes is varied linearly with time, and the
Turbine Oils by Linear Sweep Voltammetry
resulting current is recorded as a function of the potential. As
3. Summary of Test Method
the increasing voltage is applied to the prepared sample within
the cell, the various additive species under investigation within
3.1 A measured quantity of sample is dispensed into a vial
the oil are caused to electrochemically oxidize. The data
containing a measured quantity of alcohol-based electrolyte
recorded during this oxidation reaction can then be used to
solution and containing a layer of sand. When the vial is
determine the remaining useful life of the oil type. A typical
current-potential curve produced during the practice of the
1
This test method is under the jurisdiction of ASTM Committee D02 on voltammetric test can be seen by reference to Fig. 1. Initially,
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
the applied potential produces an electrochemical reaction
D02.09.0C on Oxidation of Turbine Oils.
havingaratesoslowthatvirtuallynocurrentflowsthroughthe
Current edition approved July 1, 2007. Published August 2007. Originally
cell. As the voltage is increased, as shown in Fig. 1, the
approved in 2002. Last previous edition approved in 2002 as D6810-02. DOI:
10.1520/D6810-07.
electro-active species (for example, substituted phenols) begin
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
to oxidize at the working electrode surface, producing an
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
anodic ri
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