ASTM D6869-17

Standard Test Method for Coulometric and Volumetric Determination of Moisture in Plastics Using the Karl Fischer Reaction (the Reaction of Iodine with Water)

SIGNIFICANCE AND USE
4.1 Moisture will affect the process ability of some plastics. High moisture content causes surface imperfections (that is, splay or bubbling) or degradation by hydrolysis. Low moisture (with high temperature) causes polymerization.  
4.2 The physical properties of some plastics are affected by the moisture content.
SCOPE
1.1 This method uses the reaction of Iodine (I2) with water (Karl Fischer Reaction) to determine the amount of moisture in a polymer sample.2  
1.2 This test method is intended to be used for the determination of moisture in most plastics. Plastics containing volatile components such as residual monomers and plasticizers are capable of releasing components that will interfere with the I2/water reaction.  
1.3 This method is suitable for measuring moisture over the range of 0.005 to 100 %. Sample size shall be adjusted to obtain an accurate moisture measurement.  
1.4 The values stated in SI units are regarded as the standard.
Note 1: This standard is equivalent to ISO 15512 Method B.  
1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

General Information

• Status: Published
• Publication Date: 30-Nov-2017
• ICS: 83.080.01 - Plastics in general
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.70 - Analytical Methods

Overview

ASTM D6869-17 sets the standard test method for determining moisture content in plastics using coulometric and volumetric Karl Fischer titration. Moisture levels can impact the processability and properties of many polymers, making accurate determination crucial for quality control and product performance. This test method covers the detection of water in most plastic materials, using the reaction between iodine and water as the basis for measurement. The standard is recognized internationally and is technically equivalent to ISO 15512 Method B.

Key Topics

• Moisture Determination in Plastics: Quantifies water content ranging from trace amounts (0.005%) up to 100%, supporting both highly sensitive and broader-range analysis.
• Karl Fischer Reaction: Utilizes the chemical reaction between iodine and water to quantify moisture, either through coulometric (measuring electric current) or volumetric (measuring titrant volume) procedures.
• Process Sensitivity: Moisture can cause defects such as bubbling, splay, or surface imperfections in plastics and, at high temperatures, may degrade polymers or affect polymerization.
• Interference Considerations: Some plastics with volatile components or additives, such as residual monomers and plasticizers, can interfere with the Karl Fischer reaction, affecting the accuracy of results.
• Sample Handling: Preventing moisture uptake from the atmosphere during handling and transfer is essential for reliable measurements.
• Laboratory Safety: Proper safety precautions must be maintained due to the use of high temperatures and chemicals.

Applications

The ASTM D6869-17 method is widely applied in industrial, research, and quality control environments within the plastics sector. Typical uses include:

• Manufacturing Quality Assurance: Ensures that moisture levels in polymer resins and finished parts are within specifications to prevent product defects.
• Process Optimization: Monitoring and controlling residual moisture helps manufacturers avoid costly issues such as hydrolysis, poor appearance, or mechanical failure.
• Material Characterization: Laboratories use this standard to compare batches, evaluate drying efficiency, and confirm readiness for molding or extrusion.
• Regulatory Compliance: Many industries and customers require documented moisture levels for acceptance testing or certification.

Related Standards

• ISO 15512 Method B - Plastics - Determination of Water Content (technically equivalent method)
• ASTM D4968 - Practice for Annual Review of Test Methods and Specifications for Plastics
• Other Karl Fischer Standards - Various national and international standards governing Karl Fischer moisture analysis in substances beyond plastics

Practical Value and Industry Impact

The accurate measurement of moisture in plastics ensures optimal performance, longevity, and aesthetics of plastic products. The ASTM D6869-17 standard provides a clear, reproducible, and internationally recognized method, facilitating global trade and product development. Its adoption supports manufacturers in minimizing defects and maintaining stringent quality standards, ultimately reducing waste and improving customer satisfaction.

Keywords: ASTM D6869-17, moisture determination, plastics, Karl Fischer titration, volumetric titration, coulometric titration, water content analysis, polymer quality control, ISO 15512, processability, plastics testing.

Standards Content (Sample)

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.
Designation: D6869 − 17
Standard Test Method for
Coulometric and Volumetric Determination of Moisture in
Plastics Using the Karl Fischer Reaction (the Reaction of
Iodine with Water)
This standard is issued under the fixed designation D6869; 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.
1. Scope* 3. Summary of Test Method
1.1 This method uses the reaction of Iodine (I ) with water 3.1 Samples are heated to vaporize water that is transported
(Karl Fischer Reaction) to determine the amount of moisture in by a nitrogen carrier gas to the titration cell. The moisture
a polymer sample. collected in the solution within the titration cell is determined
using the reaction of water with I .
1.2 This test method is intended to be used for the determi-
nation of moisture in most plastics. Plastics containing volatile 3.2 Endpoint detection is made by instrumented methods.
components such as residual monomers and plasticizers are Determination of the moisture present is made using the
capable of releasing components that will interfere with the reaction of I with water.
I /water reaction.
3.3 Coulometric instruments use Faraday’s law to measure
1.3 This method is suitable for measuring moisture over the the moisture present with 10.71 Coulombs (C) of generating
- -
range of 0.005 to 100 %. Sample size shall be adjusted to current corresponding to 1 mg of water (2I → I +2e ).
obtain an accurate moisture measurement. Volumetric instruments measure the volume of solution con-
taining I that is required to keep the current constant.
1.4 The values stated in SI units are regarded as the
standard.
4. Significance and Use
NOTE 1—This standard is equivalent to ISO 15512 Method B.
4.1 Moisture will affect the process ability of some plastics.
1.5 This standard does not purport to address all of the
High moisture content causes surface imperfections (that is,
safety concerns, if any, associated with its use. It is the
splay or bubbling) or degradation by hydrolysis. Low moisture
responsibility of the user of this standard to establish appro-
(with high temperature) causes polymerization.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4.2 The physical properties of some plastics are affected by
1.6 This international standard was developed in accor-
the moisture content.
dance with internationally recognized principles on standard-
5. Interferences
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5.1 Some compounds, such as aldehydes and ketones,
mendations issued by the World Trade Organization Technical
interfere in the determination of moisture content using this
Barriers to Trade (TBT) Committee.
method.
2. Referenced Documents
6. Apparatus
2.1 ISO Document: 6.1 Heating Unit, consisting of an oven capable of heating
ISO 15512 Plastics—Determination of Water Content
the sample to approximately 300°C, a furnace tube, a tempera-
turecontrolunit,acarriergasflowmeter,anddesiccatingtubes
for the carrier gas.
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
6.2 SamplePan(Boat),normallyaglasssampleboatorboat
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Dec. 1, 2017. Published January 2018. Originally
manufactured of a suitable material to transfer the oven heat to
approved in 2003. Last previous edition approved in 2011 as D6869 - 03(2011).
the sample. It is permitted to use aluminum foil as a disposable
DOI:10.1520/D6869-17.
2 liner for the sample pan.
See Appendix X1, History of Reagents Associated With the Karl Fischer
Reaction, for an explanation of coulometric and volumetric techniques as well as an
6.3 Titration Unit, consisting of a control unit, titration cell
explanation of the Karl Fischer Reaction and Karl Fischer Reagents.
with a solution cathode, platinum electrode, and solution
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. stirring capability.This apparatus has the capability to generate
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6869 − 17
or deliver iodine to react stoiciometrically with the moisture 9.4 Transfer samples quickly from sealed container to
present in the titration cell. The current or volume required to balance to instrument to prevent moisture pick-up.
generate the iodine converts to micrograms of water present.
10. Preparation of Apparatus
The percent moisture in the sample is then calculated based on
10.1 Assemble the apparatus according to the manufactur-
the sample weight used and is given as a direct digital readout.
er’s instructions. Molecular sieve or suitable desiccant must be
6.4 Analytical Balance, capable of weighing 0.1 mg (four
used in the drying tubes for the nitrogen carrier gas.
decimal place balance).
10.2 Pourapproximately200mL(oranamountspecifiedby
6.5 Glass Capillary (Micropipette), used to measure a
the manufacturer) of generator (anode) solution into the
known amount of water, typically 2 mg (2000 µg).
titration cell.
10.3 Add 10 mL of cathode solution to the cathode cell.
7. Reagents and Materials
NOTE 3—The condition of both anode and cathode solutions are
determined by the appearance of the fluids. The solutions must be light
7.1 Anode (Generator) Solution, per manufacturer’s recom-
amber in color.As solutions age, viscosity will increase and solution color
mendation.
will turn dark. The instrument will indicate solution integrity by the
7.2 Cathode Solution, per manufacturer’s recommendation.
“background” value titration rate. Do not analyze samples containing low
moisture content if the “background” value is greater than 0.10 µg/s.
NOTE 2—Hydranal or similar anode and cathode solutions are recom-
mended. These reagents do not contain pyridine, are less toxic, and have
10.4 Turn the cell power switch on. If the cell potential
no offensive odor.
shows a negative value, indicating that the anode solution
7.3 Silica Gel, granules, approximately 2 mm, desiccant for
contains excess iodine, add approximately 50 to 200 µL of
drying tube of titration assembly (if applicable).
neutralization solution or check solution.
7.4 Special Grease, as supplied by manufacturer for ground
10.5 Disconnect the tube connecting the vaporizer unit to
glass joints.
the titration cell. Set nitrogen flow rate to achieve steady
bubbling of nitrogen to the titration cell. (Aflow rate of 200 to
7.5 Molecular Sieve, or suitable desiccant (for drying the
300 mL/min is recommended.)
nitrogen carrier gas stream).
10.6 Lift the titration cell and agitate the solution by gently
7.6 Nitrogen Gas (N ), containing less than 5 µg/g of water.
swirling the cell to remove any residual water from the walls.
7.7 Neutralization Solution, or check solution (per manu-
Stir the solution for a minute in the Titration Mode to dry and
facturer’s recommendation).
stabilize the inner atmosphere.
10.7 Reconnect the tube from the vaporizer unit to the
8. Hazards
titration cell. Keep the carrier gas flow on during the whole
8.1 Due to the low quantities of water measured, maximum
titration. The instrument is now ready for sample analysis.
care shall be exercised at all times to avoid contaminating the
10.8 Set the oven and furnace tube temperature as required
sample with water from the sample container, the atmosphere
to obtain accurate results for the plastic to be tested. The
or transfer equipment. Hygroscopic resin samples shall be
temperature is set so that the analysis is completed in a short
protected from the atmosphere.
time period, yet eliminating the generation of water from
8.2 Due to the high temperatures and the chemicals in-
thermal degradation of the sample. Selection of Optimum
volved in this test method, safe lab practices must be followed
Heating Temperature is discussed below.
at all times.
10.9 Selection of Optimum Heating Temperature:
10.9.1 Select optimum heating temperature for material to
9. Sampling, Test Specimens, and Test Units
be tested by carrying out tests in several different temperatures
9.1 Unless otherwise agreed upon by interested parties or to make a curve as shown in Fig. 1.
10.9.1.1 In the range from 1 to 2, the water in the sample is
described in a specification, the material shall be sampled
statistically or the sample shall come from a process that is in not vaporized sufficiently so that
...

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: D6869 − 03 (Reapproved 2011) D6869 − 17
Standard Test Method for
Coulometric and Volumetric Determination of Moisture in
Plastics Using the Karl Fischer Reaction (the Reaction of
Iodine with Water)
This standard is issued under the fixed designation D6869; 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.
1. Scope Scope*
1.1 This method uses the reaction of Iodine (I ) with water (Karl Fischer Reaction) to determine the amount of moisture in a
polymer sample.
1.2 This test method is intended to be used for the determination of moisture in most plastics. Plastics containing volatile
components such as residual monomers and plasticizers are capable of releasing components that will interfere with the I /water
reaction.
1.3 This method is suitable for measuring moisture over the range of 0.005 to 100 %. Sample size shall be adjusted to obtain
an accurate moisture measurement.
1.4 The values stated in SI units are regarded as the standard.
NOTE 1—This standard is technically equivalent to ISO 15512 Method B.
1.5 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.
1.6 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 ISO Document:
ISO 15512 Plastics—Determination of Water Content
3. Summary of Test Method
3.1 Samples are heated to vaporize water that is transported by a nitrogen carrier gas to the titration cell. The moisture collected
in the solution within the titration cell is determined using the reaction of water with I .
3.2 Endpoint detection is made by instrumented methods. Determination of the moisture present is made using the reaction of
I with water.
3.3 Coulometric instruments use Faraday’s law to measure the moisture present with 10.71 Coulombs (C) of generating current
- -
corresponding to 1 mg of water (2I → I + 2e ). Volumetric instruments measure the volume of solution containing I that is
2 2
required to keep the current constant.
4. Significance and Use
4.1 Moisture will affect the processability process ability of some plastics. High moisture content causes surface imperfections
(that is, splay or bubbling) or degradation by hydrolysis. Low moisture (with high temperature) causes polymerization.
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Sept. 1, 2011Dec. 1, 2017. Published October 2011January 2018. Originally approved in 2003. Last previous edition approved in 20032011 as
D6869 - 03.D6869 - 03 DOI:10.1520/D6869-03R11.(2011). DOI:10.1520/D6869-17.
See Appendix X1, History of Reagents Associated With the Karl Fischer Reaction, for an explanation of coulometric and volumetric techniques as well as an explanation
of the Karl Fischer Reaction and Karl Fischer Reagents.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6869 − 17
4.2 The physical properties of some plastics are affected by the moisture content.
5. Interferences
5.1 Some compounds, such as aldehydes and ketones, interfere in the determination of moisture content using this method.
6. Apparatus
6.1 Heating Unit, consisting of an oven capable of heating the sample to approximately 300°C, a furnace tube, a temperature
control unit, a carrier gas flow meter, and desiccating tubes for the carrier gas.
6.2 Sample Pan (Boat), normally a glass sample boat or boat manufactured of a suitable material to transfer the oven heat to
the sample. It is permitted to use aluminum foil as a disposable liner for the sample pan.
6.3 Titration Unit, consisting of a control unit, titration cell with a solution cathode, platinum electrode, and solution stirring
capability. This apparatus has the capability to generate or deliver iodine to react stoiciometrically with the moisture present in the
titration cell. The current or volume required to generate the iodine converts to micrograms of water present. The percent moisture
in the sample is then calculated based on the sample weight used and is given as a direct digital readout.
6.4 Analytical Balance, capable of weighing 0.1 mg (four decimal place balance).
6.5 Glass Capillary (Micropipette), used to measure a known amount of water, typically 2 mg (2000 μg).
7. Reagents and Materials
7.1 Anode (Generator) Solution, per manufacturer’s recommendation.
7.2 Cathode Solution, per manufacturer’s recommendation.
NOTE 2—Hydranal or similar anode and cathode solutions are recommended. These reagents do not contain pyridine, are less toxic, and have no
offensive odor.
7.3 Silica Gel, granules, approximately 2 mm, desiccant for drying tube of titration assembly (if applicable).
7.4 Special Grease, as supplied by manufacturer for ground glass joints.
7.5 Molecular Sieve, or suitable desiccant (for drying the nitrogen carrier gas stream).
7.6 Nitrogen Gas (N ),containing less than 5 μg/g of water.
7.7 Neutralization Solution, or check solution (per manufacturer’s recommendation).
8. Hazards
8.1 Due to the low quantities of water measured, maximum care shall be exercised at all times to avoid contaminating the
sample with water from the sample container, the atmosphere or transfer equipment. Hygroscopic resin samples shall be protected
from the atmosphere.
8.2 Due to the high temperatures and the chemicals involved in this test method, safe lab practices must be followed at all times.
9. Sampling, Test Specimens, and Test Units
9.1 Unless otherwise agreed upon by interested parties or described in a specification, the material shall be sampled statistically
or the sample shall come from a process that is in statistical control.
9.2 Samples that will determine the moisture of a larger lot of material must be taken in such a manner that the moisture content
will not change from the original material. Sample containers must be adequately dried and the environment in which sampling
is performed must not add additional moisture to the sample. Most normal plant or lab operating conditions are adequate for
sampling. The sample container shall be properly sealed to prevent moisture pick-up before testing.
9.3 Samples in many forms, such as molded powder, molded shapes, or re-grind are permitted. It is recommended that molded
specimens be cut into smaller parts prior to testing (recommended maximum size 4 by 4 by 3 mm)
9.4 Transfer samples quickly from sealed container to balance to instrument to prevent moisture pick-up.
10. Preparation of Apparatus
10.1 Assemble the apparatus according to the manufacturer’s instructions. Molecular sieve or suitable desiccant must be used
in the drying tubes for the nitrogen carrier gas.
10.2 Pour approximately 200 mL (or an amount specified by the manufacturer) of generator (anode) solution into the titration
cell.
10.3 Add 10 mL of cathode solution to the cathode cell.
NOTE 3—The condition of both anode and cathode solutions are determined by the appearance of the fluids. The solutions must be light amber in color.
As solutions age, viscosity will increase and solution color will turn dark. The instrument will indicate solution integrity by the “background” value
D6869 − 17
titration rate. Do not analyze samples containing low moisture content if the “background” value is greater than 0.10 μg/s.
10.4 Turn the cell power switch on. If the cell potential shows a negative value, indicating that the anode solution contains
excess iodine, add approximately 50 to 200 μL of neutralization solution or check solution.
10.5 Disconnect the tube connecting the vaporizer unit to the titration cell. Set nitrogen flow rate to achieve steady bubbling
of nitrogen to the titration cell. (A flow rate of 200 to 300 mL/min is recommended.)
10.6 Lift the titration cell and agitate the solution by gently swirling the cell to remove any residual water from the walls. Stir
the solution for a minute in the Titration Mode to dry and stabilize the inn
...