ASTM D6304-04a

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An American National Standard
Designation:D6304–04a
Standard Test Method for
Determination of Water in Petroleum Products, Lubricating
1
Oils, and Additives by Coulometric Karl Fischer Titration
This standard is issued under the fixed designation D6304; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope* D4177 Practice for Automatic Sampling of Petroleum and
Petroleum Products
1.1 This test method covers the direct determination of
D 5854 Practice for Mixing and Handling of Liquid
water in the range of 10 to 25 000 mg/kg entrained water in
Samples of Petroleum and Petroleum Products
petroleum products and hydrocarbons using automated instru-
E203 TestMethodforWaterUsingVolumetricKarlFischer
mentation.Thistestmethodalsocoverstheindirectanalysisof
Titration
water thermally removed from samples and swept with dry
inert gas into the Karl Fischer titration cell. Mercaptan, sulfide
3. Summary of Test Method
−
(S or H S), sulfur, and other compounds are known to
2
3.1 An aliquot is injected into the titration vessel of a
interfere with this test method (see Section 5).
coulometricKarlFischerapparatusinwhichiodinefortheKarl
1.2 This test method is intended for use with commercially
Fisher reaction is generated coulometrically at the anode.
available coulometric Karl Fischer reagents and for the deter-
When all of the water has been titrated, excess iodine is
mination of water in additives, lube oils, base oils, automatic
detectedbyanelectrometricendpointdetectorandthetitration
transmissionfluids,hydrocarbonsolvents,andotherpetroleum
isterminated.Basedonthestoichiometryofthereaction,1mol
products.Byproperchoiceofthesamplesize,thistestmethod
ofiodinereactswith1molofwater;thus,thequantityofwater
may be used for the determination of water from mg/kg to
is proportional to the total integrated current according to
percent level concentrations.
Faraday’s Law.
1.3 Values stated in SI units are to be regarded as the
3.2 The sample injection can be done either by mass or
standard.
volume.
1.4 This standard does not purport to address all of the
3.3 The viscous samples can be analyzed by using a water
safety concerns, if any, associated with its use. It is the
vaporizer accessory that heats the sample in the evaporation
responsibility of the user of this standard to establish appro-
chamber, and the vaporized water is carried into the Karl
priate safety and health practices and determine the applica-
Fischer titration cell by a dry inert carrier gas.
bility of regulatory limitations prior to use.
4. Significance and Use
2. Referenced Documents
2 4.1 A knowledge of the water content of lubricating oils,
2.1 ASTM Standards:
additives, and similar products is important in the manufactur-
D1193 Specification for Reagent Water
ing, purchase, sale, or transfer of such petroleum products to
D1298 TestMethodforDensity,RelativeDensity(Specific
helpinpredictingtheirqualityandperformancecharacteristics.
Gravity), or API Gravity of Crude Petroleum and Liquid
4.2 For lubricating oils, the presence of moisture could lead
Petroleum Products by Hydrometer Method
toprematurecorrosionandwear,anincreaseinthedebrisload
D4052 Test Method for Density and Relative Density of
resulting in diminished lubrication and premature plugging of
Liquids by Digital Density Meter
filters, an impedance in the effect of additives, and undesirable
D4057 Practice for Manual Sampling of Petroleum and
support of deleterious bacterial growth.
Petroleum Products
5. Interferences
1
This test method is under the jurisdiction of ASTM Committee D02 on
5.1 A number of substances and classes of compounds
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
associated with condensation or oxidation-reduction reactions
D02.02 on Static Petroleum Measurement.
interferes in the determination of water by Karl Fischer
Current edition approved May 1, 2004. Published June 2004. Originally
e1
approved in 1998. Last previous edition approved in 2004 as D6304–04 . titration. In petroleum products, the most common interfer-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ences are mercaptans and sulfides. At levels of less than 500
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
mg/kg as sulfur, the interference from these compounds is
Standards volume information, refer to the standard’s Document Summary page on
insignificant for water concentrations greater than 0.02 mass
the ASTM website.
*A Summary of Changes section appears at the end of this standard.
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