ASTM D890-12(2016)

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Designation: D890 − 12 D890 − 12 (Reapproved 2016)
Standard Test Method for
Water in Liquid Pine Chemicals
This standard is issued under the fixed designation D890; 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
1.1 These test methods cover the quantitative determination of dissolved or occluded water present in any proportion in liquid
pine chemicals, such as turpentine, pinene, dipentene, pine oil, tall oil, and tall oil fatty acids. Three methods of moisture testing
are included. The Karl Fisher titration method is the preferred method for testing tall oil, Test Methods D803.
1.1.1 The Karl Fischer Titration method is based on the reaction between water and a complex reagent consisting of iodine,
sulfur dioxide, pyridine, and methanol, whereby the iodine is converted to a colorless compound. The appearance of a persistent
iodine color in the reaction mixture indicates the complete removal of free water by reaction with the reagent, and the endpoint
may be measured colorimetrically. Automatic titrators find this endpoint by the restoration of a current strength when the resistance
provided by the presence of water is eliminated. Amperometric automatic titrators find this endpoint by detecting the current flow
that occurs once water is eliminated.
1.1.2 The coulometric titration method determines water content by electronic integration of a current sufficient to generate the
precise amount of iodine from the required reagent to react with the water in the sample.
1.1.3 The azeotropic method utilizes the relatively low boiling point of water, as compared with other sample constituents, in
a toluene or xylene matrix so that water is collected in a trap and measured.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
2. Referenced Documents
2.1 ASTM Standards:
D803 Test Methods for Testing Tall Oil
D1364 Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)
3. Significance and Use
3.1 Many pine chemical products contain water as a result of the processes used for their production. Typically refined products
such as terpenes, pine oil, tall oil fatty acids, and distilled tall oil contain only traces of water, but crude tall oil might contain 0.5
to 2.5 % of water. Although the Karl Fischer and coulometric methods are most applicable to low levels of moisture, these can
be and are used at higher levels. The azeotropic distillation method is generally used at higher levels.
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 D01.34 on Pine Chemicals and Hydrocarbon Resins.
Current edition approved Nov. 1, 2012Dec. 1, 2016. Published December 2012December 2016. Originally approved in 1946. Last previous edition approved in 20082012
as D890 - 98 (2008).D890 – 12. DOI: 10.1520/D0890-12.10.1520/D0890-12R16.
This procedure has been adapted from the method of Karl Fischer published in Zeitschrift für Angewandte Chemie, Vol 48, 1935, p. 395; Chemical Abstracts, Vol Vol
29, 1935 p. 6532; as modified by Smith, Bryant, and Mitchell, Journal, Am. Chemical Soc., Vol.Vol 61, 1939, p. 2407; and further modified by Axel Johansson, Svensk
Papperstidning, Vol 50, No. 11B, 1947, p. 124; see also Publication 19 of the Swedish Wood Research Institute, Wood Chemistry and Paper Technique (Stockholm) (1947).
Karl Fischer reagent is available from various laboratory supplies. Pyridine-free adaptations of the Karl Fischer reagent are available commercially.
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’sstandard’s Document Summary page on the ASTM website.
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D890 − 12 (2016)
Moisture By Karl Fischer Titration
(Preferred method)
4. Apparatus
4.1 Titration Vessel, preferably closed, with stirring capabilities,
4.2 Buret, capable of being read at 0.1 mL divisions, or automatic buret, or
4.3 Automatic Karl Fischer titrator.
4.4 Balance, capable of weighing to the nearest 0.0001 g.
5. Reagents
5.1 Karl Fischer Reagent, or Other Suitable Reagent, such as Pyridine-free Adaptations of Karl Fischer Reagent . Reagent.
Reagents vary in strength (titer). This test method is written assuming a titer of 5 mg water/mL reagent. Recommended additions
of water in this test method may need to be adjusted depending on the titer of the reagent.
5.2 Methanol—ACS grade.
6. Standardization of Iodine Reagent
6.1 Add methanol to the titration vessel, and titrate with reagent until the lemon-yellow color just changes to a red-brown color,
or, if an automatic titrator is used, until the readings indicate no free water present. The titration vessel is now ready for titrating,
and is considered conditioned.
6.2 Add a drop of water, weighed to the nearest 0.0001 g, to the titration vessel by use of a transfer pipet, or a weighing pipet,
weighing the pipet before and after the addition. Each drop will weigh approximately 0.03 g and will require roughly 6 mL of
titrant having a titer of 5 mg/mL. Alternatively, a 25-μL, or other volume syringe may be used to introduce exact volumes.
6.3 Titrate with reagent until the lemon-yellow color just changes to a red-brown color, or, if an automatic titrator is used, until
the readings indicate no free water present. Record the mL of titrant used.
6.4 Calculate the water equivalent of the iodine reagent, in milligrams of water per millilitre of reagent, as follows:
W 31000
T 5 (1)
V
where:
T = water equivalent of the iodine reagent, mg/mL,
W = weighed water added, in g, and
V = iodine reagent, mL.
where:
T = water equivalent of the iodine reagent, mg/mL,
W = weighed water added, in g, and
V = iodine reagent, mL.
7. Procedure
7.1 Condition the titration vessel, as described in 6.1.
7.2 Add an amount of sample which will contain 50 mg or less water to the titration vessel.
7.3 Titrate to a red-brown color end point, as with previous titrations, or, if an automatic titrator is used, titrate according to the
instrument’s operating instructions.
8. Calculation
8.1 Calculate the percentage of water as follows:
V 3T
Water, %5 (2)
W 310
where:
V = i
...