ASTM D1123-99(2015)

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

SIGNIFICANCE AND USE
5.1 The total apparent water in engine coolant concentrate as determined by Karl Fischer titrations consists of the following: (1) water present in the original glycol base; (2) water added (for example, inhibitor solutions); (3) water of hydration of inhibitors (for example, Na2B4O7·5H2O); (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: 30-Apr-2015
• ICS: 71.100.45 - Refrigerants and antifreezes
• 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 2015)
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 U.S. 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-
4. Summary of Test Method
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:
D156 Test Method for Saybolt Color of Petroleum Products
I 1SO 1H O→SO 12HI (1)
2 2 2 3
(Saybolt Chromometer Method)
4.2 In order to determine water, Karl Fischer reagent is
D1176 Practice for Sampling and Preparing Aqueous Solu-
added to a solution of the sample in anhydrous high-purity
tions of Engine Coolants orAntirusts forTesting Purposes
methanol until all water present has been consumed. This is
D1193 Specification for Reagent Water
evidenced by the persistence of the orange-red end point color,
E203 Test Method for Water Using Volumetric Karl Fischer
or alternatively by an indication on a galvanometer or similar
Titration
current-indicating device that records the depolarization of a
pair of noble metal electrodes. The reagent is standardized by
3. Terminology
the titration of water.
3.1 Definitions of Terms Specific to This Standard:
NOTE 1—It is believed that these methods give all the information
required for determining the water in coolant formulations. Should
These test methods are under the jurisdiction of ASTM Committee D15 on
additional information on water determinations be needed, reference
Engine Coolants and Related Fluids and are the direct responsibility of Subcom-
should be made to Test Method E203.
mittee D15.04 on Chemical Properties.
Current edition approved May 1, 2015. Published June 2015. Originally
5. Significance and Use
approved in 1950. Last previous edition approved in 2009 as D1123 – 99(2009).
DOI: 10.1520/D1123-99R15.
5.1 The total apparent water in engine coolant concentrate
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
as determined by Karl Fischer titrations consists of the follow-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ing: (1) water present in the original glycol base; (2) water
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. added (for example, inhibitor solutions); (3) water of hydration
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1123 − 99 (2015)
of inhibitors (for example, Na B O ·5H O); (4) water formed electrodes and capable of indicating a current flow of 10 to 20
2 4 7 2
in the chemical reaction between borate and ethylene glycol, µA by means of a galvanometer or radio tuning eye circuit.
producing boratediol condensate and water; and (5) quantita-
6.4 BuretAssemblyforFischerreagent,consistingofa25or
tive interference by the reaction of the reagent with inhibitors
50-mL buret connected by means of glass (not rubber) con-
such as tetraborate or sodium hydroxide.
nectors to a source of reagent; several types of automatic
dispensing burets may be used. Since the reagent loses
TEST METHOD A—MANUAL TITRATION
strength when exposed to moist air, all vents must be protected
against atmospheric moisture by adequate drying tubes con-
6. Apparatus
taining anhydrous calcium sulfate. All stopcocks and joints
6.1 Titration Vessel—For color end point titrations, use a 7
should be lubricated with a lubricant not particularly reactive
100 or 250-mLvolumetric flask, which need not be calibrated.
with the reagent.
For instrument end point, a 250-mL flask fitted with inter-
6.5 Weighing Bottle, of the Lunge or Grethen type, or
changeable electrodes (Fig. 1) may be used. This is particu-
equivalent.
larly good for titrations of coolant concentrate that is deeply
coloredfromdyeoranyothercause.Forpermanentlymounted 6.6 Some laboratory equipment suppliers offer a Karl Fis-
assemblies, the vessel should have a capacity about equal to
cher apparatus. The noted model or its equivalent has been
that of a 300-mLtall-form beaker and should be provided with found to be suitable.
a tight-fitting closure to protect the sample and reagent from
atmospheric moisture, a stirrer, and a means of adding sample 7. Reagents
and reagents and removing spent reaction mixture. It is
7.1 Purity of Reagents—Reagent grade chemicals shall be
desirable to have a means for cooling the titration vessel to ice
used in all tests. Unless otherwise indicated, it is intended that
temperature.
all reagents shall conform to the specifications of the Commit-
6.2 Instrument Electrodes, platinum with a surface equiva-
tee onAnalytical Reagents of theAmerican Chemical Society,
lent to two No. 26 wires, 4.76-mm long. The wires should be
where such specifications are available. Other grades may be
3to8mmapartandsoinsertedinthevesselthattheliquidwill
used, provided it is first ascertained that the reagent is of
cover them. sufficiently high purity to permit its use without lessening the
accuracy of the determination.
6.3 Instrument Depolarization Indicator, having an internal
resistance of less than 5000 Ω and consisting of a means of 7.2 Unless otherwise indicated, references to water shall be
impressing and showing a voltage of 20 to 50 mV across the
understood to mean reagent water, Type IV, conforming to
Specification D1193.
7.3 Karl Fischer Reagent, equivalent to 5 mg of water/
mL.
Flasks made by Rankin Glass Blowing Co., 3920 Franklin Canyon Rd.,
7.4 Methanol (Warning—See 8.1.)—Anhydrous, high pu-
Martinez, CA have been found satisfactory for this purpose.
rity.
8. Hazards
8.1 Methanol—Poison; flammable; may be fatal or cause
blindness if swallowed; cannot be made non-poisonous; harm-
ful if inhaled.
A type similar to the Precision Scientific Co. “Aquatrator” or Fisher Scientific
Co. “FisherTitrimeter,” is suitable for the measurement of the instrument end point.
A type similar to Catalog No. J-821 of Scientific Glass Apparatus Co.,
Bloomfield, NJ, or Catalog No. 750 of Eck and Krebs, New York, NY, has been
specifically designed for this purpose and presents the minimum contact of reagent
with stopcock lubricant.
Indicating Drierite has been found satisfactory for this purpose.
Suitable lubricants includeApiezon N. (James G. Biddle and Co., Philadelphia,
PA); High Vacuum Silicone Grease (Dow Corning Co., Midland, MI); Sisco 300
(Swedish Iron and Steel Co., New York, NY).
Metrohm Herisau, Karl Fischer Titrator Type E-452 available from Brinkmann
Instruments, Inc., Cantaigue Road, Westbury, NY 11590.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD.
NOTE 1—All dimensions in millimetres.
Reagents, as the pyridine-free hydranal reagent, available from Fisher
FIG. 1 Titration Flask Assembly Scientific, Pittsburgh, PA 15219.
D1123 − 99 (2015)
it is sufficient to lower the tip of the buret deeply into the long neck of the
9. Sampling
titration flask.
9.1 A representative sample of the contents of the original
NOTE 3—In titrating with the volumetric flask-type titration vessel,
container shall be obtained as directed in Practice D1176; even
avoidwettingthestopperandupperendoftheflaskwitheitherthereagent
orthesamplesolvent.Eachtimethetitrationisinterrupted,touchtheburet
if two phases are present, the water-insoluble phase should not
tip to the neck of the flask to remove droplets which, if not removed,
be separated.
would absorb moisture from the atmosphere. When the flask is removed
fromundertheburettip,wipethetipwithacleandryclothinadownward
10. Standardization of Reagent
motion.
10.1 Standardize the Fischer reagent at least once, prior to
12. Calculation
use, each day the procedure is used, by either the color or
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
Water, weight% 5 VF/10M (3)
purity methanol. Stir rapidly. Titrate with Karl Fischer reagent
where:
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
V = mL of Karl Fischer reagent required by the sample,
F = equivalency factor for Karl Fischer reagent, mg of
again and record the volume of titrant used. Repeat standard-
ization two more times. water per mL of reagent, and
M = sample used, g.
10.1.2 Calculate the equivalency factor of the reagent in
terms of water content per millilitre as follows:
13. Precision and Bias
Equivalency factor, F , mg of water/mL 5 A/B (2)
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
ratory should not be considered suspect unless it differs from
instrument end point apparatus is used, that the electrodes are
that of another laboratory by more than the following amount:
covered by this amount of methanol. If the color end point is to
Water Content, % Reproducibility, % of mean
be determined, make up a second flask as well.
0.1to1.0 15
11.2 Adjust the stirrer, if any, to provide adequate mixing
1.0to10 5
without splashing. Titrate the mixture to the instrument end
13.2 Bias—Since there is no accepted reference material
point (3.1.2), or the color end point (3.1.1), with Karl Fischer
suitable for determining the bias for the procedure in this test
reagent.Ifthecolorendpointistobeobserved,titrateoneflask
method, bias has not been determined.
to match the first. Set aside the first flask as a comparison
standard for titrating the sample.
TEST METHOD B—COULOMETRIC TITRATION
11.3 To the titration mixture thus prepared, add an amount
14. Apparatus
of sample as indicated in Table 1. Exercise care when the
11,12
sample is transferred so that water is not absorbed from the air,
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-
Provide a small hole for introducing the buret tip. In less humid climates
tralize a known number of micrograms of water per minute.
14.3 In order to determine the water content of engine
coolants, this method requires a two-part titration solution that
TABLE 1 Recommended Sample Sizes
is brought to zero dryness by iodine produced by the generator
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 (2015)
when the instrument is powered up. The sample is added and the needle through the sample port septum and lower it until
the water content is read d
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D1123 − 99 (Reapproved 2009) D1123 − 99 (Reapproved 2015)
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 U.S. Department of Defense.
1. 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.
2. Referenced Documents
2.1 ASTM Standards:
D156 Test Method for Saybolt Color of Petroleum Products (Saybolt Chromometer Method)
D1176 Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
D1193 Specification for Reagent Water
E203 Test Method for Water Using Volumetric Karl Fischer Titration
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 color end point—that point during the titration when the color change from yellow to orange-red is sharp and easily
repeated. The orange-red color must persist for at least 30 s in order to indicate an end point.
These test methods are under the jurisdiction of ASTM Committee D15 on Engine Coolants and Related Fluids and are the direct responsibility of Subcommittee D15.04
on Chemical Properties.
Current edition approved Nov. 1, 2009May 1, 2015. Published December 2009June 2015. Originally approved in 1950. Last previous edition approved in 20032009 as
ε1
D1123 – 99(2003)(2009). . DOI: 10.1520/D1123-99R09.10.1520/D1123-99R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3.1.1.1 Discussion—
View the color by transmitted daylight or by transmitted light from an artificial daylight lamp, such as one that complies with the
specification given in Test Method D156.
3.1.2 instrument end point—for the purpose of these tests, that point in the titration when two small platinum electrodes, upon
which a potential of 20 to 50 mV has been impressed, are depolarized by the addition of 0.05 mL of Fischer reagent (6 mg of
water/mL), causing a change of current flow of 10 to 20 μA that persists for at least 30 s.
3.1.2.1 Discussion—
This end point is sometimes incorrectly called the “dead stop,” which is the reverse of the above.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1123 − 99 (2015)
4. Summary of Test Methods Method
4.1 These test methods are based essentially on the reduction of iodine by sulfur dioxide in the presence of water. This reaction
can be used quantitatively only when pyridine and an alcohol are present to react as follows:
I 1SO 1H O→SO 12HI (1)
2 2 2 3
4.2 In order to determine water, Karl Fischer reagent is added to a solution of the sample in anhydrous high-purity methanol
until all water present has been consumed. This is evidenced by the persistence of the orange-red end point color, or alternatively
by an indication on a galvanometer or similar current-indicating device that records the depolarization of a pair of noble metal
electrodes. The reagent is standardized by the titration of water.
NOTE 1—It is believed that these methods give all the information required for determining the water in coolant formulations. Should additional
information on water determinations be needed, reference should be made to Test Method E203.
5. Significance and Use
5.1 The total apparent water in engine coolant concentrate as determined by Karl Fischer titrations consists of the fol-following:
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 B O ·5H O); (4) water formed in the chemical reaction between borate and ethylene glycol, producing
2 4 7 2
boratediol condensate and water; and (5) quantitative interference by the reaction of the reagent with inhibitors such as tetraborate
or sodium hydroxide.
NOTE 1—All dimensions in millimetres.
FIG. 1 Titration Flask Assembly
TEST METHOD A—MANUAL TITRATION
6. Apparatus
6.1 Titration Vessel—For color end point titrations, use a 100 or 250-mL volumetric flask, which need not be calibrated. For
instrument end point, a 250-mL flask fitted with interchangeable electrodes (Fig. 1) may be used. This is particularly good for
titrations of coolant concentrate that is deeply colored from dye or any other cause. For permanently mounted assemblies, the
vessel should have a capacity about equal to that of a 300-mL tall-form beaker and should be provided with a tight-fitting closure
to protect the sample and reagent from atmospheric moisture, a stirrer, and a means of adding sample and reagents and removing
spent reaction mixture. It is desirable to have a means for cooling the titration vessel to ice temperature.
6.2 Instrument Electrodes, platinum with a surface equivalent to two No. 26 wires, 4.76-mm long. The wires should be 3 to 8
mm apart and so inserted in the vessel that the liquid will cover them.
Flasks made by Rankin Glass Blowing Co., 3920 Franklin Canyon Rd., Martinez, CA have been found satisfactory for this purpose.
D1123 − 99 (2015)
6.3 Instrument Depolarization Indicator, having an internal resistance of less than 5000 Ω and consisting of a means of
impressing and showing a voltage of 20 to 50 mV across the electrodes and capable of indicating a current flow of 10 to 20 μA
by means of a galvanometer or radio tuning eye circuit.
6.4 Buret Assembly for Fischer reagent, consisting of a 25 or 50-mL buret connected by means of glass (not rubber) connectors
to a source of reagent; several types of automatic 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 containing anhydrous calcium
6 7
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 Fischer 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 Committee 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 lessening the accuracy of the determination.
7.2 Unless otherwise indicated, references to water shall be understood to mean reagent water, Type IV, conforming to
Specification D1193.
7.3 Karl Fischer Reagent, equivalent to 5 mg of water/mL.
7.4 Methanol (Warning—See 8.1.)—Anhydrous, high purity.
8. Hazards
8.1 Methanol—Poison; flammable; may be fatal or cause blindness if swallowed; cannot be made non-poisonous; harmful if
inhaled.
9. Sampling
9.1 A representative sample of the contents of the original container shall be obtained as directed in Test Method Practice
D1176; even if two phases are present, the water-insoluble phase should not be separated.
10. Standardization of Reagent
10.1 Standardize the Fischer reagent at least once, prior to use, each day the procedure is used, by either the color or instrument
end point (see Section 3) method, using the procedure as used for titrating the sample (Section 11).
10.1.1 Add to each 250 mL flask 25 mL of anhydrous, high purity methanol. Stir rapidly. Titrate with Karl Fischer reagent
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 again
and record the volume of titrant used. Repeat standardization two more times.
10.1.2 Calculate the equivalency factor of the reagent in terms of water content per millilitre as follows:
Equivalency factor, F , mg of water/mL 5 A/B (2)
where:
A = mg of water used in the standardization, and
B = Karl Fischer reagent required, mL.
11. Procedure
11.1 Introduce 30 to 50 mL of the anhydrous high-purity methanol into a 250 mL Erlenmeyer flask, making sure, if an
instrument end point apparatus is used, that the electrodes are covered by this amount of methanol. If the color end point is to be
determined, make up a second flask as well.
A type similar to the Precision Scientific Co. “Aquatrator” or Fisher Scientific Co. “Fisher Titrimeter,” is suitable for the measurement of the instrument end point.
A type similar to Catalog No. J-821 of Scientific Glass Apparatus Co., Bloomfield, NJ, or Catalog No. 750 of Eck and Krebs, New York, NY, has been specifically
designed for this purpose and presents the minimum contact of reagent with stopcock lubricant.
Indicating Drierite has been found satisfactory for this purpose.
Suitable lubricants include Apiezon N. (James G. Biddle and Co., Philadelphia, PA); High Vacuum Silicone Grease (Dow Corning Co., Midland, MI); Sisco 300 (Swedish
Iron and Steel Co., New York, NY).
Metrohm Herisau, Karl Fischer Titrator Type E-452 available from Brinkmann Instruments, Inc., Cantaigue Road, Westbury, NY 11590.
Reagent Chemicals, American Chemical Society Specifications, , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
Reagents, as the pyridine-free hydranal reagent, available from Fisher Scientific, Pittsburgh, PA 15219.
D1123 − 99 (2015)
11.2 Adjust the stirrer, if any, to provide adequate mixing without splashing. Titrate the mixture to the instrument end point
(3.1.2), or the color end point (3.1.1), with Karl Fischer reagent. If the color end point is to be observed, titrate one flask to match
the first. Set aside the first flask as a comparison standard for titrating the sample.
11.3 To the titration mixture thus prepared, add an amount of sample as indicated in Table 1. Exercise care when the sample
is transferred so that water is not absorbed from the air, particularly under conditions of high humidity. Again, titrate the mixture
with Karl Fischer reagent to the same instrument or color end point previously employed. Record the amount of reagent used to
titrate the water in the sample.
NOTE 2—When using the volumetric flask-type titration vessel in humid climate, place a piece of thin paraffin wax over the mouth of the vessel. Provide
a small hole for introducing the buret tip. In less humid climates it is sufficient to lower the tip of the buret deeply into the long neck of the titration flask.
NOTE 3—In titrating with the volumetric flask-type titration vessel, avoid wetting the stopper and upper end of the flask with either the reagent or the
sample solvent. Each time the titration is interrupted, touch the buret 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 from under the buret tip, wipe the tip with a clean dry cloth in a downward motion.
12. Calculation
12.1 Calculate the total water content (free plus apparent) of the sample as follows:
Water, weight %5 VF/10M (3)
where:
V = mL of Karl Fischer reagent required by the sample,
F = equivalency factor for Karl Fischer reagent, mg of water per mL of reagent, and
M = sample used, g.
13. Precision and Bias
13.1 Precision—The following data should be used for judging the acceptability of results (95 % probability):
13.1.1 Repeatability—Duplicate results by the same operator should be considered suspect if they differ by more than the
following amount:
Repeatability 0.5 mL of titrant
13.1.2 Reproducibility—The result submitted by one laboratory should not be considered suspect unless it differs from that of
another laboratory by more than the following amount:
Water Content, % Reproducibility, % of mean
0.1 to 1.0 15
1.0 to 10 5
13.2 Bias—Since there is no accepted reference material suitable for determining the bias for the procedure in this test method,
bias has not been determined.
TEST METHOD B—COULOMETRIC TITRATION
14. Apparatus
11,12
14.1 Coulometric Titrator —A complete control unit with titration chamber and clamp, platinum sensing electrodes,
generator, magnetic stirrer, and meeting requirements 14.2 and 18.1.
14.2 The instrument used for determining water in liquids is designed and calibrated to deliver a known number of milliamperes
of current which generates sufficient iodine to neutralize a known number of micrograms of water per minute.
This procedure is patented by the Photovolt Corp. under U. S. Patent 3,726,778 and has been included in the standard under Paragraph 11.2 of the Regulations Governing
ASTM Technical Committees. Procedure A is a non-patented alternative method.
A detailed drawing is available from ASTM Headquarters. Request Adjunct No. 12-415330-00.
TABLE 1 Recommended Sample Sizes
Sample
Water Content,
...