ASTM D1364-95(1999)
(Test Method)Standard Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)
Standard Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)
SCOPE
1.1 This test method covers the determination of water in volatile solvents and chemical intermediates used in paint, varnish, lacquer, and related products.
1.2 This test method is not applicable in the presence of mercaptans, peroxides, or appreciable quantities of aldehydes or amines.
1.3 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.
1.4 For hazard information and guidance, see the supplier's Material Safety Data sheet.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 1364 – 95 (Reapproved 1999)
Standard Test Method for
Water in Volatile Solvents (Karl Fischer Reagent Titration
Method)
This standard is issued under the fixed designation D 1364; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope orange-red color must persist for at least 30 s in order to
indicate an end point.
1.1 This test method covers the determination of water in
volatile solvents and chemical intermediates used in paint,
NOTE 2—View the color by transmitted daylight or by transmitted light
varnish, lacquer, and related products. from an artificial daylight lamp, such as the one that complies with the
specifications given in Test Method D 1500.
1.2 This test method is not applicable in the presence of
mercaptans, peroxides, or appreciable quantities of aldehydes
4. Summary of Test Method
or amines.
4.1 This test method is based essentially upon the reduction
1.3 This standard does not purport to address all of the
of iodine by sulfur dioxide in the presence of water. This
safety concerns, if any, associated with its use. It is the
reaction can be used quantitatively only when pyridine and an
responsibility of the user of this standard to establish appro-
alcohol are present to react with the sulfur trioxide and
priate safety and health practices and determine the applica-
hydriodic acid produced according to the following reactions:
bility of regulatory limitations prior to use.
1.4 For hazard information and guidance, see the supplier’s
H O 1 I 1 SO 1 3C H N → 2C H N·HI 1 C H N·SO
2 2 2 5 5 5 5 5 5 3
Material Safety Data sheet. C H N·SO 1 ROH → C H N·HSO R
5 5 3 5 5 4
(1)
2. Referenced Documents
4.2 To determine water, Karl Fischer reagent (a solution of
2.1 ASTM Standards:
iodine, pyridine, and sulfur dioxide, in the molar ratio of
D 1500 Test Method for ASTM Color of Petroleum Prod-
1 + 10 + 3) dissolved in anhydrous 2-methoxyethanol is added
ucts (ASTM Color Scale)
to a solution of the sample in anhydrous pyridine-ethylene
glycol (1 + 4) until all water present has been consumed. This
3. Terminology
is evidenced by the persistence of the orange-red end-point
3.1 Definitions of Terms Specific to This Standard:
color; or alternatively by an indication on a galvanometer or
3.1.1 instrumental end point—that point in the titration
similar current-indicating device which records the depolariza-
when two small platinum electrodes, upon which a potential of
tion of a pair of noble-metal electrodes. The reagent is
20 to 50 mV has been impressed, are depolarized by the
standardized by titration of water.
addition of 0.05 mL of Karl Fischer reagent (6 mg of H O per
5. Significance and Use
mL), causing a change of current flow of 10 to 20 μA that
persists for at least 30 s.
5.1 Volatile solvents are used in a variety of chemical
processes which may be affected by water. Therefore, this test
NOTE 1—This end point is sometimes incorrectly called the “dead stop”
method provides a test procedure for assessing compliance
which is the reverse of the above.
with a specification.
3.1.2 color end point—During the titration, the solution first
turns yellow, then later deepens towards the end of the titration;
6. Apparatus
the end point is indicated by the change from yellow to
6.1 Titration Vessel—For color end point titrations, use a
orange-red which is quite sharp and easily repeated. The
100 or 250-mL volumetric flask, which need not be calibrated;
a 250-mL flask fitted with interchangeable electrodes (Fig. 1)
This test method is under the jurisdiction of ASTM Committee D-1 on Paint
and Related Coatings, Materials, and Applications and is the direct responsibility of The sole source of supply of flasks known to the committee at this time is the
Subcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates. Rankin Glass Blowing Co., 3920 Franklin Canyon Road, Martinez, CA. If you are
Current edition approved April 15, 1995. Published June 1995. Originally aware of alternative suuppliers, please provide this information to ASTM Head-
published as D 1364 – 55 T. Last previous edition D 1364 – 90. quarters. Your comments will receive careful consideration at a meeting of the
2 1
Annual Book of ASTM Standards, Vol 05.01. responsibile technical committee, which you may attend.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 1364 – 95 (1999)
taining indicating calcium sulfate drying agent. All stopcocks
and joints should be lubricated with a lubricant not particularly
reactive with the reagent.
6.5 Weighing Bottle, of the Lunge or Grethen Type, or
equivalent.
7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
tee on Analytical Reagents of the American Chemical Society,
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without decreasing the
accuracy of the determination.
7.1.1 Karl Fischer Reagent (equivalent to 6 mg of H O per
mL) —For each liter of solution, dissolve 133 6 1gofI in
4256 2 mL of anhydrous (less than 0.1 % H O) pyridine in a
dry glass-stoppered bottle. Add 425 6 2 mL of anhydrous (less
than 0.1 % H O) 2-methoxyethanol. Cool to below 4°C in an
ice bath and add gaseous SO , dried by bubbling through
NOTE 1—All dimensions in millimetres.
concentrated H SO (sp gr 1.84); determine the amount of SO
2 4 2
FIG. 1 Titration Flask Assembly
added by measuring the change in weight of the SO cylinder
(102 6 1 g) or the increase in volume (70 6 1 mL) of the
reagent mixture. Alternatively, add 70 mL of freshly drawn
may also be used for the instrumental end point and is
liquid SO in small increments.
particularly suitable for titrations at ice temperatures. For
7.1.2 Solvent Mixture—Mix 1 volume of anhydrous (less
permanently mounted assemblies, the vessel should have a
than 0.1 % H O) pyridine with 4 volumes of anhydrous (less
capacity about equal to that of a 300-mL tall-form beaker; and
than 0.1 % H O) ethylene glycol.
be provided with a tight-fitting closure to protect the sample
and reagent from atmospheric moisture, a stirrer, and a means
NOTE 3—Pyridine, ethylene glycol, and 2-methoxyethanol, each con-
of adding sample and reagents and removing spent reaction
taining less than 0.1 % water, are available and should be used.
mixture. It is desirable to have a means for cooling the titration
NOTE 4—If adequately dry reagents cannot be procured, they can each
be dried by distillation through a multiple-plate column, discarding the
vessel to ice temperature.
first 5 % of material distilling overhead and using the 95 % remaining.
6.2 Instrument Electrodes—Platinum with a surface equiva-
Drying may also be accomplished by the addition of 1 volume of toluene
lent to two No. 26 wires 5 mm long. The wires should be 3 to
or cyclohexane to 19 volumes of the pyridine-glycol, or of the pyridine
8 mm apart and so inserted in the vessel that 25 mL of liquid
ethylene glycol monomethyl ether mixture, followed by distillation; the
will cover them.
first 5 % distilled is discarded and the residual 95 % is used.
6.3 Instrument Depolarization Indicator, having an internal
8. Sampling
resistance of less than 5000 V and consisting of a means of
impressing and showing a voltage of 20 to 50 mV across the
8.1 Hygroscopic Solvents, including for example, ketones,
electrodes and capable of indicating a current flow of 10 to 20
acetates, alcohols, and glycol ethers, absorb ambient moisture.
μA by means of a galvanometer or radiotuning eye circuit.
It is essential to avoid changes in the water content of these
6.4 Buret Assembly for Karl Fischer reagent, consisting of a
materials during sampling operations. Errors from this source
25 or 50-mL buret connected by means of glass (not rubber)
are particularly significant in the analysis of materials having
connectors to a source of reagent; several types of automatic
low water content. When analyzing materials that absorb
dispensing burets may be used. Since the reagent loses
ambient water readily, limit as much as possible contact with
strength when exposed to moist air, all vents must be protected
air in transferring the specimen into the titration vessel. Avoid
against atmospheric moisture by adequate drying tubes con-
intermediate sample containers, if possible.
4 6
The sole source of supply of instrument depolarization indicator known to the Reagent Chemicals, American Chemical Society Specifications, American
committee at this time is Fisher Scientific Co. (need address). If you are aware of Chemical Society, Washington, DC. For suggestions on the testing of reagents
...
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