ASTM D2108-97

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 2108 – 97 An American National Standard
Standard Test Method for
Color of Halogenated Organic Solvents and
Their Admixtures (Platinum-Cobalt Scale)
This standard is issued under the fixed designation D 2108; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
TABLE 1 Platinum-Cobalt Color Standards
1. Scope
Color Stock Color Stock
1.1 This test method covers the visual measurement of the
Standard Solution, Standard Solution,
color of halogenated organic solvents and their admixtures. It
Number mL Number mL
is valid for values of 50 platinum-cobalt (Pt-Co) units or less.
5 1 35 7
1.2 This standard does not purport to address all of the
10 2 40 8
15 3 50 10
safety concerns, if any, associated with its use. It is the
20 4 60 12
responsibility of the user of this standard to establish appro-
25 5 70 14
priate safety and health practices and determine the applica-
30 6 100 20
500 100
bility of regulatory limitations prior to use.
2. Significance and Use
used in all tests. Unless otherwise indicated, it is intended that
2.1 Color may be indicative of the quality of the solvent
all reagents shall conform to the specifications of the Commit-
because any color present is due to the presence of contami-
tee on Analytical Reagents of the American Chemical Society,
nants.
where such specifications are available. Other grades may be
3. Apparatus
used, provided it is first ascertained that the reagent is of
3.1 Color Comparison Tubes—Matched 50 or 100-mL, sufficiently high purity to permit its use without lessening the
accuracy of the determination.
tall-form Nessler tubes, provided with ground-on, optically
clear, glass caps. 4.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean distilled water or water of
3.2 Color Comparator—A color comparator constructed to
equal purity.
permit visual comparison of light transmitted through tall-
4.3 Cobaltous Chloride —(CoCl ·6H O).
form, Nessler tubes in the direction of their longitudinal axes.
2 2
4.4 Hydrochloric Acid (sp gr 1.19)—Concentrated hydro-
The comparator should be constructed so that white light is
chloric acid (HCl).
passed through or reflected off a white glass plate and directed
4.5 Potassium Chloroplatinate —(K PtCl ).
with equal intensity through the tubes and should be shielded
2 6
so that no light enters the tubes from the side.
5. Preparation of Color Standards
NOTE 1—There are numerous colorimeters and comparators commer-
5.1 Platinum-Cobalt Stock Solution—Dissolve 1.245 g of
cially available that measure the color of liquids and take some of the
K PtCl and 1.000 g of CoCl ·6H O in water. Add 100 mL of
2 6 2 2
subjectivity out of the measurement. These instruments may be calibrated
HCl (sp gr 1.19) and dilute to 1 L with water. This solution has
with the platinum-cobalt color standards listed in Table 1 or with optically
standardized color filter disks such as those available for the Hellige Aqua a color of 500.
Tester. Many of these instruments take the measurement across a relatively
NOTE 2—Stock solutions of Pt-Co 500 color may be purchased from
narrow range of wave lengths, and their readings may be in error if the
reagent supply houses. The stock solution should be certified reagent or
color of the sample is significantly different from the amber color of the
verified by the user as being correct.
color standards.
5.2 Platinum-Cobalt Standards—For 100-mL Nessler
4. Reagents
tubes, prepare color standards as given in Table 1. D
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