ASTM D1123-99

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Designation:D1123–99
Standard Test Methods for
Water in Engine Coolant Concentrate by the Karl Fischer
1
Reagent Method
This standard is issued under the fixed designation D 1123; 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 (ε) 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 3.1.1.1 Discussion—View the color by transmitted daylight
or by transmitted light from an artificial daylight lamp, such as
1.1 These test methods cover the determination of the water
one that complies with the specification given in Test Method
present in new or unused glycol-based coolant concentrates
D 156.
using a manual (Test MethodA) or an automatic (Test Method
3.1.2 instrument end point—for the purpose of these tests,
B) coulometric titrator procedure.
that point in the titration when two small platinum electrodes,
1.2 Many carbonyl compounds react slowly with the Fis-
upon which a potential of 20 to 50 mVhas been impressed, are
cher reagent, causing a fading end point and leading to high
depolarized by the addition of 0.05 mL of Fischer reagent (6
results. A modified Fischer reagent procedure is included that
mg of water/mL), causing a change of current flow of 10 to 20
minimizes these undesirable and interfering reactions.
µA that persists for at least 30 s.
1.3 This standard does not purport to address all of the
3.1.2.1 Discussion—This end point is sometimes incor-
safety problems, if any, associated with its use. It is the
rectly called the “dead stop,” which is the reverse of the above.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Summary of Test Methods
bilityofregulatorylimitationspriortouse.Forspecifichazards
4.1 These test methods are based essentially on the reduc-
statements see Sections 8 and 16.
tion of iodine by sulfur dioxide in the presence of water. This
2. Referenced Documents reaction can be used quantitatively only when pyridine and an
alcohol are present to react as follows:
2.1 ASTM Standards:
D 156 Test Method for Saybolt Color of Petroleum Prod- I 1 SO 1 H O→ SO 1 2HI (1)
2 2 2 3
2
ucts (Saybolt Chromometer Method)
D 1176 Test Method for Sampling and Preparing Aqueous
4.2 In order to determine water, Karl Fischer reagent is
Solutions of Engine Coolants or Antirusts for Testing
added to a solution of the sample in anhydrous high-purity
3
Purposes
methanol until all water present has been consumed. This is
4
D 1193 Specification for Reagent Water
evidenced by the persistence of the orange-red end point color,
3
E 203 Test Method for Water Using Karl Fischer Reagent
or alternatively by an indication on a galvanometer or similar
current-indicating device that records the depolarization of a
3. Terminology
pair of noble metal electrodes. The reagent is standardized by
3.1 Definitions:
the titration of water.
3.1.1 color end point—that point during the titration when
NOTE 1—It is believed that these methods give all the information
the color change from yellow to orange-red is sharp and easily
required for determining the water in coolant formulations. Should
repeated. The orange-red color must persist for at least 30 s in
additional information on water determinations be needed, reference
order to indicate an end point.
should be made to Test Method E 203.
5. Significance and Use
1
These test methods are under the jurisdiction of ASTM Committee D-15 on
5.1 The total apparent water in engine coolant concentrate
Engine Coolants and are the direct responsibility of Subcommittee D15.04 on
as determined by Karl Fischer titrations consists of the fol-
Chemical Properties.
Current edition approved May 10, 1999. Published August 1999. Originally
lowing: (1) water present in the original glycol base; (2) water
published as D 1123 – 50. Last previous edition D 1123 – 93.
added (for example, inhibitor solutions); (3) water of hydration
2
Annual Book of ASTM Standards, Vol 05.01.
3
of inhibitors (for example, Na B O ·5H O); ( 4) water formed
Annual Book of ASTM Standards, Vol 15.05. 2 4 7 2
4
Annual Book of ASTM Standards, Vol 11.01. in the chemical reaction between borate and ethylene glycol,
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D1123
producing boratediol condensate and water; and ( 5) quantita- 6.4 Buret Assembly for Fischer reagent, consisting of a 25
tive interference by the reaction of the reagent with inhibitors or 50-mL buret connected by means of gla
...