ASTM D4017-22

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: D4017 − 02 (Reapproved 2015) D4017 − 22
Standard Test Method for
Water in Paints and Paint Materials by Karl Fischer Method
This standard is issued under the fixed designation D4017; 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 This test method is applicable to all paints and paint materials, including resins, monomers, and solvents, with the exception
of aldehydes and certain active metals, metal oxides, and metal hydroxides. While the evaluation was limited to pigmented
products containing amounts of water in the 3030 % to 70 % range, there is reason to believe that higher and lower concentrations
can be determined by this test method.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D3960 Practice for Determining Volatile Organic Compound (VOC) Content of Paints and Related Coatings
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
(Withdrawn 2009)
E203 Test Method for Water Using Volumetric Karl Fischer Titration
2.2 Other Standard:
EPA Federal Reference Method 24 Determination of Volatile Matter Content, Density, Volume Solids, and Weight Solids of
Surface Coatings
This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.
Current edition approved June 1, 2015Dec. 1, 2022. Published June 2015December 2022. Originally approved in 1981. Last previous edition approved in 20082015 as
ε1
D4017 – 02 (2008)(2015). . DOI: 10.1520/D4017-02R15.10.1520/D4017-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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D4017 − 22
3. Summary of Test Method
3.1 The material is dissolved in a suitable solvent, and titrated directly with standardized Karl Fischer reagent, to an electrometric
end point. The sluggish reaction with water in pyridine is accelerated with a chemical catalyst, 1-ethylpiperidine.
3.1.1 Karl Fischer reagent is a mixture of iodine, amine, sulfur dioxide, and an alcohol. In the reaction with water, iodine is
reduced to hydrogen iodide. Once all the water is consumed, the appearance of free iodine is detected electrochemically and the
titration is stopped. The following depicts the chemistry that takes place:
ROH + SO + RN ↔ (RNH)SO R
2 3
H O + I + (RNH)SO R + 2RN→ (RNH)SO R + 2(RNH)I
2 2 3 4
3.2 In classical Karl Fischer titrations the base used is pyridine, and the solvent either methanol or methoxy ethanol. In order to
accelerate the reaction when pyridine is used, 1-ethylpiperidine is used as a catalyst/buffer. The additional buffer capacity is usually
already built in to most nonpyridine based reagents such as hydranal (see Hydranal Manual).
4. Significance and Use
4.1 Control of water content is often important in controlling the performance of paint and paint ingredients, and it is critical in
controlling volatile organic compound (VOC) content.
4.2 Paint materials are often insoluble in common Karl Fischer solvents such as methanol. Pyridine has been found to be a nearly
universal solvent for these materials; however, the Karl Fischer reaction is too slow in that solvent at room temperature. To speed
it up, 1-ethylpiperidine is added at 5 % as a buffer, or “catalyst.”
4.3 For nonpyridine-based reagents, a number of different solvent systems are available to increase solubility and to minimize
interferences from ketones and aldehydes.
5. Apparatus
5.1 Karl Fischer Apparatus, manual or automatic, encompassed by the description in Test Method E203. Apparatus should be
equipped with a 25-mL buret, Class A, or equivalent.
5.2 Syringe, 100-μL capacity, with needle.
5.3 Syringes, 1-mL and 10-mL capacity, without needle, but equipped with caps.
6. Reagents
6.1 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 ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
6.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent grade water conforming
to Type II of Specification D1193.
6.3 Classical Karl Fischer Reagent.
6.3.1 Nonpyridine Based Karl Fischer Reagent (KFR).
Available from Hoechst Celanese Corporation, Hydranal Technical Center, U.S. Highway 43, Bucks, AL 36512.
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.
So-K-3 available from Fischer Scientific Co., or equivalent has been found suitable for this purpose.
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TABLE 1 Specimen Guidelines
Approximate Approximate
Expected
Specimen Titrant Volume
water,
Weight, at 5 mg/mL
%
g titre, mL
0.5–1.0 5 5–10
1–3 2–5 10–20
3–10 1–2 10–20
10–30 0.4–1.0 20–25
30–70 0.1–0.4 15–25
>70 0.1 20
TABLE 1 Specimen Guidelines
Approximate Approximate
Expected
Specimen Titrant Volume
water,
Weight, at 5 mg/mL
%
g titre, mL
0.5–1.0 5 5–10
1–3 2–5 10–20
3–10 1–2 10–20
10–30 0.4–1.0 20–25
30–70 0.1–0.4 15–25
>70 0.1 20
6.4 Pyridine.
6.5 1-Ethylpiperidine.
6.6 Hydrochloric Acid (HCl), concentrated.
NOTE 1—All reagents must be fresh. Do not use reagents that are more than 9nine months old. Karl Fischer reagent deteriorates with age. Check expiration
dates on the reagent bottle.
7. Hazards
7.1 Karl Fischer reagent contains four toxic compounds, namely iodine, sulfur dioxide, pyridine, and methanol or glycol ether.
Prepare and dispense the reagent in a hood. Care must be exercised to avoid inhalation or skin contact. Following accidental
contact or spillage, wash with large quantities of water.
7.2 Treat pyridine and methanol solvents with the same care as Karl Fischer reagent.
7.3 1-ethylpiperidine is of unknown toxicity and, therefore, handle with the same care as the materials listed in 7.1 and 7.2.
7.4 Handle also nonpyridine based reagents with the same care as the chemicals listed in 7.1 and 7.2.
8. Procedure
NOTE 2—Some instruments perform many of the following procedures and calculations automatically; consult instrument manual for details.
8.1 Standardization of Karl Fischer Reagent:
8.1.1 Add enough fresh solvent to cover the electrode tip. If using pyridine, also add 1 mL of 1-ethylpiperidine catalyst per 20
mL of pyridine. Catalyst performs best at a concentration of about 5 % of the volume present.
8.1.2 Fill the 100-μL syringe to about half full with distilled water and weigh to the nearest 0.1 mg.
Use 1-ethylpiperidine, manufactured by the Aldrich Chemical Co., Milwaukee, WI 53233, for the best results.
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8.1.3 Pretitrate the solvent to the end point indicated by the equipment manufacturer, by adding just enough Karl Fischer Reagent
I (KFR) to cause the end point to hold for at least 30 s.
8.1.3.1 The use of the catalyst greatly increases the reaction rate between water and Karl Fischer reagent. To obtain reliable results,
increase the electrode sensitivity and reduce titration rate to a minimum. Most instruments have controls for these functions.
Consult the instructional manual for information on these controls.
8.1.4 Empty the contents of the syringe into the titrator vessel. Immediately replace the stopper of the sample port and titrate with
KFR to the end point as described in 8.1.3.
8.1.5 Repeat standardization until replicate values of F agree within 1 %. Determine the mean of at least two such determinations.
Carry out calculations retaining at least one extra decimal figure beyond that of the acquired data. Round off figures after final
calculations.
8.1.6 Calculation:
8.1.6.1 Calculate the KFR titre F as follows:
F 5 J/P (1)
where:
J = water added, g, and
P = KFR used, mL.
The value for F should be recorded to the four significant digits and should be the mean of at least two determinations. Typical
values are in the range of 0.0040000.004000 g ⁄mL to 0.006000 g/mL.
8.2 Analysis of Samples With More Than 0.5 % Water:
8.2.1 The titration vessel should already contain pretitrated solvent and catalyst, as described in 8.1.1 and 8.1.3 in the
standardization procedure. Best results are obtained with fresh solvent, that is, containing no previously titrated specimen in the
vessel.
8.2.2 With a 1-mL or 10-mL syringe, draw the amount of material indicated in Table 1.
NOTE 3—Paint samples tend to settle in the syringe and give high percent water content. Obtain a freshly stirred or mixed specimen for each test run.
8.2.2.1 Remove the syringe from the specimen, pull the plunger out a little further, wipe the excess material off the syringe, and
place a cap on the syringe tip. Weigh the filled syringe to the nearest 0.1 mg.
8.2.3 Remove the cap, and empty the syringe contents into the pretitrated solvent vessel. Pull the plunger out and replace the cap.
8.2.4 Stir rapidly for 11 min to 2 min before starting titration. Some instruments can be set to do this automatically. If the specimen
is still not dissolved or dispersed, continue stirring until it is dissolved, or use a different solvent in place of solvent in 8.2.1.
8.2.5 Titrate the specimen slowly with KFR to the end point described in 8.1.3.
8.2.6 Reweigh the emptied syringe, and calculate the specimen weight by difference.
8.2.7 Calculation:
8.2.7.1 Calculate the percent water L as follows:
L 5 P 3F 3100 /S (2)
~ !
8.3 Analysis of Materials With Less Than 0.5 % Water:
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8.3.1 For 0.10.1 % to 0.5 %, follow procedure in 8.2 (1-g specimen), except substitute a 1-mL microburet for the 25-mL buret in
the Karl Fischer apparatus.
8.3.2 For less than 0.1 %, use a 1-mL microburet and increase specimen size as much as needed, up to 10 g. It should be possible
to measure moisture levels down to 1 ppm (0.0001 %) by this approach.
NOTE 4—Specimens with less than 0.1 % water may require special handling techniques to prevent pickup of atmospheric moisture. The precision of this
test method was determined with specimens containing higher water levels.
9. Recommendations for Good Results
9.1 Make sure electrodes are clean.
9.2 Follow manufacturer’s instructions to ensure that venting into the titration vessel is only through a dessicant.
9.3 Samples should be thoroughly mixed before taking a specimen.
9.4 Use an appropriate solvent/reagent for the paint/coating being analyzed. Paints and paint materials are often slow to dissolve
or disperse. To ensure that all of the water is extracted into the pyridine or solvent, stir rapidly for 11 min or 2 min before starting
the titration.
9.5 Run the titration slowly with rapid stirring.
9.6 Throw out the first result in fresh pyridine.
9.7 Use only Aldrich’s 1-ethylpiperidine. It has been found that other brands produce variable results.
9.8 For difficult-to-dissolve samples, extract the water with a suitable solvent, such as dry methanol. An example of this procedure
is outlined in Appendix X1.
10. Maintenance
10.1 Cleanup—Clean the titration vessel by rinsing with fresh pyridine. Do not use methanol or other solvents.
10.2 Dryness—Check frequently to be sure that all drying tubes are in good condition and tightly connected. Replace dessicant
when indicator color changes through half of the tube.
10.3 Electrode Performance—If electrode response is sluggish or otherwise off standard, take the following steps, in turn, to
correct the problem. Test the electrode with a titration after each step, to determine if the next step is required.
10.3.1 Wipe the electrode tip with a clean paper towel.
10.3.2 Wash the electrode by dipping in concentrated hydrochloric acid for at least 1 min. Rinse first with distilled water, then with
methanol.
10.3.3 Follow manufacturer’s instructions on resetting end point meter.
10.3.4 Replace power source. See manual for replacement procedure.
10.3.5 Replace the electrode.
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11. Precision and Bias
11.1 The precision estimates are based on an interlaboratory study in which one operator in each of seven different laboratories
analyzed in duplicate on two different days seven samples of water-based paints of various types containing between 2525 % to
75 % water. The results were analyzed statistically in accordance with Practice E180. The within-laboratory coefficient of variation
was found to be 0.9 % relative at 23 df, and the between-laboratory coefficient of variation was 1.9 % relative, at 18 df. Based on
these coefficients, the following criteria should be used for judging the acceptability of results at the 95 % confidence level.
11.1.1 Repeatability—Two results, each the mean of duplicate determinations, obtained by the same operator on different days
should be considered suspect if they differ by more than 3.5 % relative.
11.1.2 Reproducibility—Two results, each the mean of duplicate determinations, obtained by operators in different laboratories
should be considered suspect if they differ by more than 5.5 % relative.
11.2 Bias—Bias cannot be determined because there are no accepted standards for water content of paints.
12. Keywords
12.1 Karl Fischer reagent method; moisture content; water content
APPENDIXES
(Nonmandatory Information)
X1. TEST METHOD FOR KARL FISCHER WATER DETERMINATION FOR LATEX PAINTS USING
EXTRACTION WITH METHANOL
X1.1 Scope
X1.1.1 If variable results are obtained with the pyridine method, the methanol extraction method is recommended.
X1.1.2 This test method is applicable to paints based on latex technology, which may not be sufficiently soluble in the solvents
specified in the direct titration method. Some solvent-based paints will “ball up” in contact with methanol.
X1.1.3 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.
X1.2 Referenced Documents
X1.2.1 ASTM Standards: D3960 Practice for Determining Volatile Organic Compound (VOC) Content of Paints and Related
Coatings
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D01-1096. Contact ASTM Customer
Service at service@astm.org.
Isopropanol has also been found suitable in some cases.
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X1.2.2 Other Standard: EPA Reference Method 24, Determination of Volatile Matter Content, Water Content, Density, Volume
Solids, and Weight Solids of Surface Coatings
X1.3 Summary of Test Method
X1.3.1 Water is quantitatively extracted from a sample with anhydrous methanol, and an aliquot is titrated for water content using
commercial non-pyridine based reagents.
X1.4 Significance and Use
X1.4.1 The latex polymers in some modern coatings are not soluble, and do not readily give up their water, in pyridine or other
solvents used in this test method. This procedure is designed to quantitatively extract the water, in a reasonable time, into
anhydrous methanol, so it can be easily titrated. This test method may not be applicable to all coating types, and is offered as an
alternative to the direct titration method in Test Method D4017.
X1.4.2 This test method is specifically designed to obtain VOC content of waterborne coatings with minimum error.
X1.4.3 The specimen size assumes a paint that has 50 to 90 % water content. If the product being tested has a lower expected water
content, larger specimens should be taken.
X1.4.4 Good results are dependent on close attention to detail. See X1.12, Recommendations for Good Results.
X1.4.5 For further information see Practice D3960, EPA Reference Method 24, and Manual 4.
X1.5 Apparatus
X1.5.1 Karl Fischer Titration Apparatus.
X1.5.2 Disposable Syringe, 1-cc tuberculin with cap and needle.
X1.5.3 Disposable Syringe, 1-cc tuberculin with cap and no needle.
X1.5.4 Analytical Balance, with tare bar, readable to 0.0001 g.
MNL, 4, Manual on Determination of Volatile Organic Compound (VOC) Content in Paints, Inks, and Related Coating Products, ASTM, 1993.
The Metrohm Model E-358 was used in the development of this test method. (Brinkmann Instruments, Cantiague Rd., Westbury, NY 11590). A few references to its
features are mentioned in the Procedure. Most modern Karl Fischer titrators have comparable features. This model is no longer available, but several companies, including
Brinkmann, market equivalent instruments.
Disposible syringe, BD 9625, available from many scientific supply companies, has been found suitable for this purpose.
Disposible syringe, BD 9602, available from many scientific supply companies, has been found suitable for this purpose.
D4017 − 22
X1.5.5 Sonic Bath.
X1.5.6 Flasks, 100-mL, Class A volumetric.
X1.5.7 Pipetes, 10 mL, Class A volumetric.
X1.6 Reagents
X1.6.1 Non-Pyridine Composite Karl Fischer Reagent, (KFR) 5 mg/mL titre.
X1.6.2 Reagent Grade Methanol or commercial anhydrous methanol.
X1.6.3 4A Molecular Sieve, 8–12 mesh beads (required only if drying your own material).
X1.7 Sample Preparation
X1.7.1 Dry Methanol: Put about 200 g of 4A molecular sieve beads into a fresh 4-L bottle of reagent grade methanol and allow
to stand overnight.
X1.7.2 Into two 100-mL volumetric flasks, add about 80 mL of dry methanol and stopper.
X1.7.3 Fill a 1-mL disposable syringe (the type with no needle) with freshly mixed sample of the paint to be tested. Draw back
th
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