ASTM D1123-99(2009)

Standard Test Methods for Water in Engine Coolant Concentrate by the Karl Fischer Reagent Method

SIGNIFICANCE AND USE
The total apparent water in engine coolant concentrate as determined by Karl Fischer titrations consists of the fol-
lowing: (1) water present in the original glycol base; (2) water added (for example, inhibitor solutions); (3) water of hydration of inhibitors (for example, Na 2B4O7·5H2O); ( 4) water formed in the chemical reaction between borate and ethylene glycol, producing boratediol condensate and water; and ( 5) quantitative interference by the reaction of the reagent with inhibitors such as tetraborate or sodium hydroxide.
SCOPE
1.1 These test methods cover the determination of the water present in new or unused glycol-based coolant concentrates using a manual (Test Method A) or an automatic (Test Method B) coulometric titrator procedure.  
1.2 Many carbonyl compounds react slowly with the Fischer reagent, causing a fading end point and leading to high results. A modified Fischer reagent procedure is included that minimizes these undesirable and interfering reactions.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety problems, 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. For specific hazards statements see Sections 8 and 16.

General Information

• Status: Historical
• Publication Date: 31-Oct-2009
• Technical Committee: D15 - Engine Coolants and Related Fluids
• Drafting Committee: D15.04 - Chemical Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D1123 − 99(Reapproved 2009)
Standard Test Methods for
Water in Engine Coolant Concentrate by the Karl Fischer
Reagent Method
This standard is issued under the fixed designation D1123; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3.1.1 color end point—that point during the titration when
the color change from yellow to orange-red is sharp and easily
1.1 These test methods cover the determination of the water
repeated. The orange-red color must persist for at least 30 s in
present in new or unused glycol-based coolant concentrates
order to indicate an end point.
using a manual (Test MethodA) or an automatic (Test Method
3.1.1.1 Discussion—View the color by transmitted daylight
B) coulometric titrator procedure.
or by transmitted light from an artificial daylight lamp, such as
1.2 Many carbonyl compounds react slowly with the Fis-
one that complies with the specification given in Test Method
cher reagent, causing a fading end point and leading to high
D156.
results. A modified Fischer reagent procedure is included that
3.1.2 instrument end point—for the purpose of these tests,
minimizes these undesirable and interfering reactions.
that point in the titration when two small platinum electrodes,
1.3 The values stated in SI units are to be regarded as
upon which a potential of 20 to 50 mVhas been impressed, are
standard. No other units of measurement are included in this
depolarized by the addition of 0.05 mL of Fischer reagent (6
standard.
mg of water/mL), causing a change of current flow of 10 to 20
µA that persists for at least 30 s.
1.4 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the 3.1.2.1 Discussion—Thisendpointissometimesincorrectly
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-
bilityofregulatorylimitationspriortouse.Forspecifichazards 4. Summary of Test Methods
statements see Sections 8 and 16.
4.1 These test methods are based essentially on the reduc-
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
2.1 ASTM Standards:
alcohol are present to react as follows:
D156 Test Method for Saybolt Color of Petroleum Products
I 1SO 1H O→SO 12HI (1)
2 2 2 3
(Saybolt Chromometer Method)
D1176 Practice for Sampling and Preparing Aqueous Solu-
4.2 In order to determine water, Karl Fischer reagent is
tions of Engine Coolants orAntirusts forTesting Purposes
added to a solution of the sample in anhydrous high-purity
D1193 Specification for Reagent Water
methanol until all water present has been consumed. This is
E203 Test Method for Water Using Volumetric Karl Fischer
evidenced by the persistence of the orange-red end point color,
Titration
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 of Terms Specific to This Standard:
the titration of water.
NOTE 1—It is believed that these methods give all the information
These test methods are under the jurisdiction of ASTM Committee D15 on
required for determining the water in coolant formulations. Should
Engine Coolants and Related Fluids and are the direct responsibility of Subcom-
additional information on water determinations be needed, reference
mittee D15.04 on Chemical Properties.
should be made to Test Method E203.
Current edition approved Nov. 1, 2009. Published December 2009. Originally
´1
approved in 1950. Last previous edition approved in 2003 as D1123 – 99(2003) .
5. Significance and Use
DOI: 10.1520/D1123-99R09.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1 The total apparent water in engine coolant concentrate
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
as determined by Karl Fischer titrations consists of the fol-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. lowing: (1) water present in the original glycol base; (2) water
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1123 − 99 (2009)
added (for example, inhibitor solutions); (3) water of hydration electrodes and capable of indicating a current flow of 10 to 20
of inhibitors (for example, Na B O ·5H O); (4) water formed µA by means of a galvanometer or radio tuning eye circuit.
2 4 7 2
in the chemical reaction between borate and ethylene glycol,
6.4 BuretAssemblyforFischerreagent,consistingofa25or
producing boratediol condensate and water; and (5) quantita-
50-mL buret connected by means of glass (not rubber) con-
tive interference by the reaction of the reagent with inhibitors
nectors to a source of reagent; several types of automatic
such as tetraborate or sodium hydroxide.
dispensing burets may be used. Since the reagent loses
strength when exposed to moist air, all vents must be protected
against atmospheric moisture by adequate drying tubes con-
taining anhydrous calcium sulfate. 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.
6.6 Some laboratory equipment suppliers offer a Karl Fis-
cher apparatus. The noted model or its equivalent has been
found to be suitable.
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 onAnalytical Reagents of theAmerican 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 lessening the
accuracy of the determination.
7.2 Unless otherwise indicated, references to water shall be
NOTE 1—All dimensions in millimetres.
understood to mean reagent water, Type IV, conforming to
FIG. 1 Titration Flask Assembly
Specification D1193.
7.3 Karl Fischer Reagent, equivalent to 5 mg of water/
TEST METHOD A—MANUAL TITRATION 10
mL.
6. Apparatus 7.4 Methanol (Warning—See 8.1.)—Anhydrous, high pu-
rity.
6.1 Titration Vessel— For color end point titrations, use a
100 or 250-mLvolumetric flask, which need not be calibrated.
8. Hazards
For instrument end point, a 250-mL flask fitted with inter-
8.1 Methanol—Poison; flammable; may be fatal or cause
changeable electrodes (Fig. 1) may be used. This is particu-
larly good for titrations of coolant concentrate that is deeply blindness if swallowed; cannot be made non-poisonous; harm-
ful if inhaled.
coloredfromdyeoranyothercause.Forpermanentlymounted
assemblies, the vessel should have a capacity about equal to
that of a 300-mLtall-form beaker and should be provided with
a tight-fitting closure to protect the sample and reagent from 4
A type similar to the Precision Scientific Co. “Aquatrator” or Fisher Scientific
Co. “FisherTitrimeter,” is suitable for the measurement of the instrument end point.
atmospheric moisture, a stirrer, and a means of adding sample
A type similar to Catalog No. J-821 of Scientific Glass Apparatus Co.,
and reagents and removing spent reaction mixture. It is
Bloomfield, NJ, or Catalog No. 750 of Eck and Krebs, New York, NY, has been
desirable to have a means for cooling the titration vessel to ice
specifically designed for this purpose and presents the minimum contact of reagent
temperature.
with stopcock lubricant.
Indicating Drierite has been found satisfactory for this purpose.
6.2 Instrument Electrodes, platinum with a surface equiva-
Suitable lubricants includeApiezon N. (James G. Biddle and Co., Philadelphia,
lent to two No. 26 wires, 4.76-mm long. The wires should be
PA); High Vacuum Silicone Grease (Dow Corning Co., Midland, MI); Sisco 300
(Swedish Iron and Steel Co., New York, NY).
3to8mmapartandsoinsertedinthevesselthattheliquidwill
Metrohm Herisau, Karl Fischer Titrator Type E-452 available from Brinkmann
cover them.
Instruments, Inc., Cantaigue Road, Westbury, NY 11590.
Reagent Chemicals, American Chemical Society Specifications , American
6.3 Instrument Depolarization Indicator, having an internal
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
resistance of less than 5000 Ω and consisting of a means of
listed by the American Chemical Society, see Analar Standards for Laboratory
impressing and showing a voltage of 20 to 50 mV across the
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD.
3 10
Flasks made by Rankin Glass Blowing Co., 3920 Franklin Canyon Rd., Reagents, as the pyridine-free hydranal reagent, available from Fisher
Martinez, CA have been found satisfactory for this purpose. Scientific, Pittsburgh, PA 15219.
D1123 − 99 (2009)
Provide a small hole for introducing the buret tip. In less humid climates
9. Sampling
it is sufficient to lower the tip of the buret deeply into the long neck of the
9.1 A representative sample of the contents of the original
titration flask.
container shall be obtained as directed in Test Method D1176;
NOTE 3—In titrating with the volumetric flask-type titration vessel,
avoidwettingthestopperandupperendoftheflaskwitheitherthereagent
even if two phases are present, the water-insoluble phase
orthesamplesolvent.Eachtimethetitrationisinterrupted,touchtheburet
should not be separated.
tip to the neck of the flask to remove droplets which, if not removed,
would absorb moisture from the atmosphere. When the flask is removed
10. Standardization of Reagent
fromundertheburettip,wipethetipwithacleandryclothinadownward
motion.
10.1 Standardize the Fischer reagent at least once, prior to
use, each day the procedure is used, by either the color or
12. Calculation
instrument end point (see Section 3) method, using the proce-
12.1 Calculatethetotalwatercontent(freeplusapparent)of
dure as used for titrating the sample (Section 11).
the sample as follows:
10.1.1 Add to each 250 mL flask 25 mL of anhydrous, high
purity methanol. Stir rapidly. Titrate with Karl Fischer reagent
Water, weight% 5 VF/10M (3)
according to 11.2. Add to the solution 0.15 to 0.18 g of water
(to 60.1 mg) by use of an accurately sized syringe. Titrate
where:
again and record the volume of titrant used. Repeat standard-
V = mL of Karl Fischer reagent required by the sample,
ization two more times.
F = equivalency factor for Karl Fischer reagent, mg of
10.1.2 Calculate the equivalency factor of the reagent in
water per mL of reagent, and
terms of water content per millilitre as follows:
M = sample used, g.
Equivalency factor, F , mg of water/mL 5 A/B (2)
13. Precision and Bias
13.1 Precision—The following data should be used for
where:
judging the acceptability of results (95 % probability):
A = mg of water used in the standardization, and
13.1.1 Repeatability—Duplicate results by the same opera-
B = Karl Fischer reagent required, mL.
tor should be considered suspect if they differ by more than the
following amount:
11. Procedure
Repeatability 0.5 mL of titrant
11.1 Introduce 30 to 50 mL of the anhydrous high-purity
13.1.2 Reproducibility—The result submitted by one labo-
methanol into a 250 mL Erlenmeyer flask, making sure, if an
instrument end point apparatus is used, that the electrodes are ratory should not be considered suspect unless it differs from
that of another laboratory by more than the following amount:
covered by this amount of methanol. If the color end point is to
be determined, make up a second flask as well.
Water Content, % Reproducibility, % of mean
11.2 Adjust the stirrer, if any, to provide adequate mixing
0.1to1.0 15
without splashing. Titrate the mixture to the instrument end 1.0to10 5
point (3.1.2), or the color end point (3.1.1), with Karl Fischer
13.2 Bias—Since there is no accepted reference material
reagent.Ifthecolorendpointistobeobserved,titrateoneflask
suitable for determining the bias for the procedure in this test
to match the first. Set aside the first flask as a comparison
method, bias has not been determined.
standard for titrating the sample.
TEST METHOD B—COULOMETRIC TITRATION
11.3 To the titration mixture thus prepared, add an amount
of sample as indicated in Table 1. Exercise care when the
14. Apparatus
sample is transferred so that water is not absorbed from the air,
11,12
14.1 Coulometric Titrator —A complete control unit
particularly under conditions of high humidity. Again, titrate
with titration chamber and clamp, platinum sensing electrodes,
themixturewithKarlFischerreagenttothesameinstrumentor
generator, magnetic stirrer, and meeting requirements 14.2 and
color end point previously employed. Record the amount of
18.1.
reagent used to titrate the water in the sample.
14.2 The instrument used for determining water in liquids is
NOTE2—Whenusingthevolumetricflask-typetitrationvesselinhumid
designed and calibrated to deliver a known number of milli-
climate, place a piece of thin paraffin wax over the mouth of the vessel.
amperes of current which generates sufficient iodine to neu-
tralize a known number of micrograms of water per minute.
TABLE 1 Recommended Sample Sizes 14.3 In order to determine the water content of engine
coolants, this method requires a two-part titration solution that
Sample
Water Content,
Size, Sample Method
weight %
g
ThisprocedureispatentedbythePhotovoltCorp.underU.S.Patent3,726,778
2.5 to 10 0.3 Introduce samples by using weigh bottles or
and has been included in the standard under Paragraph 11.2 of the Regulations
disposable, accurate syringes. Obtain sample
GoverningASTM Technical Committees. ProcedureAis a non-patented alternative
weight by difference.
method.
0.5to2.5 3
Below 0.5 20 A detailed drawing is available from ASTM Headquarters. Request Adjunct
No. 12-415330-00.
D1123 − 99 (2009)
is brought to zero dryness by iodine produced by the generator the needle through the sample port septum and lower it until
when the instrument is powered up. The sample is added and the tip of the nee
...