ASTM D444-88(2008)
(Test Method)Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate Yellow)
SIGNIFICANCE AND USE
This test method has been developed to standardize the chemical analysis of zinc chromate yellow pigment and to provide alternate methods of analysis for chromium and zinc.
SCOPE
1.1 These test methods cover procedures for the chemical analysis of the pigment known commercially as “zinc yellow” or “ zinc chromate yellow.”
1.2 The analytical procedures appear in the following order:
Sections Moisture and Other Volatile Matter7 Combined Water8 Chromium: Dichromate Method 9-11 Thiosulfate Method9, 12, and 13 Zinc: Hydroxyquinoline Method9, 14, and 15 Ferrocyanide Method9, 16, and 17 Alkaline Salts18 and 19 Sulfates20 and 21 Chlorides22 and 23 Matter Insoluble in Dilute Acetic
Acid24 Coarse Particles25
1.3 The values stated in SI units are to be considered the standard. The values given in parentheses are for information only.
1.4 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.
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Designation: D444 − 88(Reapproved 2008)
Standard Test Methods for
Chemical Analysis of Zinc Yellow Pigment (Zinc Chromate
Yellow)
This standard is issued under the fixed designation D444; 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 D478 Specification for Zinc Yellow (Zinc Chromate) Pig-
ments
1.1 These test methods cover procedures for the chemical
D1193 Specification for Reagent Water
analysis of the pigment known commercially as “zinc yellow”
E11 Specification for Woven Wire Test Sieve Cloth and Test
or “zinc chromate yellow.”
Sieves
1.2 The analytical procedures appear in the following order:
E50 Practices for Apparatus, Reagents, and Safety Consid-
Sections
erations for Chemical Analysis of Metals, Ores, and
Moisture and Other Volatile Matter 7
Related Materials
Combined Water 8
Chromium:
Dichromate Method 9–11
3. Significance and Use
Thiosulfate Method 9, 12, and 13
Zinc: 3.1 This test method has been developed to standardize the
Hydroxyquinoline Method 9, 14, and 15
chemical analysis of zinc chromate yellow pigment and to
Ferrocyanide Method 9, 16, and 17
provide alternate methods of analysis for chromium and zinc.
Alkaline Salts 18 and 19
Sulfates 20 and 21
Chlorides 22 and 23
4. Preparation of Sample
Matter Insoluble in Dilute Acetic 24
Acid
4.1 Mix the laboratory sample thoroughly. Take a sufficient
Coarse Particles 25
quantity for the chemical analyses and pass it through a
1.3 The values stated in SI units are to be considered the
180-µm (No. 80) sieve, grinding in a mortar if necessary.
standard. The values given in parentheses are for information
NOTE 1—Detailed requirements for this sieve are given in Specification
only.
E11.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 5. Reagents
responsibility of the user of this standard to establish appro-
5.1 Purity of Reagents—Unless otherwise indicated, it is
priate safety and health practices and determine the applica-
intended that all reagents shall conform to the specifications of
bility of regulatory limitations prior to use.
theCommitteeonAnalyticalReagentsoftheAmericanChemi-
cal Society, where such specifications are available. Other
2. Referenced Documents
grades may be used, provided it is first ascertained that the
2.1 ASTM Standards:
reagent is of sufficiently high purity to permit its use without
D185 Test Methods for Coarse Particles in Pigments
lessening the accuracy of the determination.
D280 Test Methods for Hygroscopic Moisture (and Other
5.2 Purity of Water—Unless otherwise indicated, references
Matter Volatile Under the Test Conditions) in Pigments
to water for use in the preparation of reagents and in analytical
procedures shall conform to Type II reagent water, in Specifi-
cation D1193.
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.31 on Pigment Specifications.
Current edition approved Feb. 1, 2008. Published February 2008. Originally
approved in 1937. Last previous edition approved in 2003 as D444 – 88 (2003). Reagent Chemicals, American Chemical Society Specifications, American
DOI: 10.1520/D0444-88R08. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D444 − 88 (2008)
6. Precision 11. Procedure
6.1 Precision statements have not been established. 11.1 Pipet50mLofthesolutionofthespecimen(Section7)
into a 600-mLbeaker.Add 200 to 250 mLof water and 10 mL
MOISTURE AND OTHER VOLATILE MATTER
of H SO (sp gr 1.84). Cool to 35°C or below.
2 4
7. Procedure
11.2 Add an excess of ferrous ammonium sulfate solution
and back-titrate with 0.1 N K Cr O solution, using ortho-
2 2 7
7.1 Determine moisture and other volatile matter in accor-
phenanthroline indicator. Carry out a blank titration of the
dance with Test Method A of Test Methods D280.
sameamountofferrousammoniumsulfatesolutionatthesame
COMBINED WATER
time and in the same manner.
11.3 Calculation—Calculate the percent of chromium C as
8. Procedure
CrO , as follows:
8.1 Weigh to 0.1 mg3gofthe oven-dried material from the
C 5 ~B 2 V !N 30.03334/S 3100
1 1 1 1
determinationofmoistureandothervolatilematter(Note2and
Note 3), and place in a porcelain boat. Introduce the boat with
where:
the charge into a refractory combustion tube in an electrically-
B =K Cr O solution required for titration of the
1 2 2 7
heated combustion furnace of the type used for the determina-
blank, mL,
tion of carbon in steel by direct combustion (Note 4). Place the
V =K Cr O solution required for back-titration of
1 2 2 7
boat at the center of the combustion tube maintained at a
the specimen, mL,
temperature of 1000°C for 4 h. Draw a current of pure dry air
N = normality of the K Cr O solution, and
1 2 2 7
or dry nitrogen through the tube to sweep the evolved moisture
S = specimen in the aliquot used, g.
into a previously weighed absorption tube containing anhy-
0.03334 = milliequivalents weight of CrO .
drous magnesium perchlorate (Mg(ClO ) ) or other efficient
4 2
11.4 Alternatively, the solution of the specimen may be
desiccant. The weight increase of the absorption tube repre-
titrated directly with the ferrous ammonium sulfate solution,
sents the “combined water.”
using an electrometric titration assembly to detect the end
NOTE 2—Loss on ignition of the pigment does not suffice for the
point. Standardize the ferrous solution against K Cr O .
2 2 7
determination of combined water in zinc yellow.
NOTE 3—If the pigment contains an organic treating agent, first remove
CHROMIUM BY THE THIOSULFATE TEST
this treating agent by washing with ether or chloroform.
METHOD
NOTE 4—See Apparatus No. 1 for the determination of total carbon by
direct combustion as described in Practices E50.
12. Reagents
SPECIMEN SOLUTION FOR DETERMINATION OF
12.1 Potassium Iodide Solution (150 g/L)—Dissolve 150 g
CHROMIUM AND ZINC
of potassium iodide (KI) in water and dilute to 1 L.
9. Procedure
12.2 Sodium Thiosulfate, Standard Solution (0.1 N)—
Dissolve 24.8 g of sodium thiosulfate of (Na S O ·5H O) in
9.1 Weigh to 0.1 mg about a 4-g specimen and mix with 50
2 2 3 2
1 L of freshly boiled and cooled water contained in a sterile
mL of cold sulfuric acid (H SO ) (1+5). It should dissolve
2 4
glass bottle. If sulfur precipitates during preparation or upon
completelyatthisstage(Note5).Dilutethesolutionto500mL
subsequent use, discard the solution and prepare a new one.
in a volumetric flask.
Standardize against iodine.
NOTE 5—A cloudy solution may result if the pigment contains a
surface-treating agent. In this case, it usually can be cleared by cooling in 12.3 Starch Indicator Solution—Stir up 2 to3gof potato
an ice-bath and filtering through a medium porosity fritted disk. If the
starch with 100 mL salicylic acid solution (1 %), and boil the
solution is not clarified by this treatment, extract a portion of the original
mixture until the starch is practically dissolved, then dilute to
sample with a solvent such as chloroform before the analysis is begun.
1 L with water.
CHROMIUM BY THE DICHROMATE TEST
13. Procedure
METHOD
13.1 Pipet a 25-mL aliquot of the solution of the specimen
10. Reagents
(Section 9) into a 500-mLglass-stoppered Erlenmeyer iodime-
10.1 Ferrous Ammonium Sulfate Solution—Dissolve 80 g of
tricflaskorothersuitableglass-stopperedbottlecontaining200
ferrous ammonium sulfate (FeSO · (NH ) SO ·6H O) in 50
4 4 2 4 2
mL of H SO (1+39). Add 20 mL of KI solution (150 g/L),
2 4
mL of H SO (sp gr 1.84) and enough water to make 1 L of
2 4
stopper, and allow the solution to stand for approximately 5
solution. Mix thoroughly before use. This solution is approxi-
min.
mately 0.2 N.
13.2 Titratetheliberatediodinewith0.1 NNa S O solution
2 2 3
10.2 Ortho-Phenanthroline Indicator Solution—0.5 % in
at room temperature until the reddish brown iodine color
water.
becomes quite faint.Add 5 mL of starch solution and continue
10.3 Potassium Dichromate, Standard Solution—(0.1 N)— the titration until the final color change becomes pale green
Dissolve 4.9035 g of dried potassium dichromate (K Cr O )in with no blue tinge. Titrate this final titration by swirling the
2 2 7
water and dilute to 1 L in a volumetric flask. flask at least three times after each addition of the Na S O
2 2 3
D444 − 88 (2008)
solution, being sure that there is no further color change, 16.2 Potassium Ferrocyanide, Standard Solution—Dissolve
especially at the final stage of the titration.The green end point 22 g of potassium ferrocyanide (K Fe(CN)·3H O) in water
4 6 2
is definite and sharp. and dilute to 1 L.To standardize, transfer 0.2 g of metallic zinc
or freshly ignited ZnO to a 400-mL beaker. Dissolve in 10 mL
13.3 Calculation—Calculate the percent of chromium C as
of hydrochloric acid (HCl, sp gr 1.19) and 20 mL of water.
CrO as follows:
Drop in a small piece of litmus paper, add ammonium
C 5 V N 30.03334 /S 3100
@~ ! #
2 2 2
hydroxide (NH OH) until slightly alkaline, then add HCl until
just acid, and then 3 mL more of HCl. Dilute to about 250 mL
where:
with hot water and heat nearly to boiling. Run in the
V =Na S O solution required for titration of the
2 2 2 3
K Fe(CN) solution slowly from a buret, while stirring
4 6
specimen, mL
constantly, until a drop tested on a white porcelain plate with a
N = normality of the Na S O solution, and
2 2 2 3
drop of the uranyl indicator solution shows a brown tinge after
S = specimen in the aliquot used, g.
standing 1 min. Do not allow the temperature of the solution to
ZINC BY THE HYDROXYQUINOLINE TEST
fall below 70°C during the titration. Run a blank using the
METHOD
same amounts of reagents and water as in the standardization.
The standardization must be made under the same conditions
(Suitable if No Interfering Substances Are Present)
of temperature, volume, and acidity as obtained when the
specimen is titrated. Calculate the strength of the K Fe(CN)
14. Reagents
4 6
solution in terms of grams of zinc as follows:
14.1 Acetone Solution of 8-Hydroxyquinoline (50 g/L)—
Z 5 W/ V 2 B
~ !
Dissolve5gof 8-hydroxyquinoline in 100 mL of acetone. 3 2
where:
15. Procedure
Z = zinc equivalent of the K Fe(CN) solution, g/mL,
4 6
15.1 Pipet50mLofthesolutionofthespecimen(Section9)
W = zinc used (or equivalent to the ZnO used), g,
into a 250-mL beaker and dilute to 100 mL with water. Add 5
V =K Fe(CN) solution required for titration of the
3 4 6
to 10 g of ammonium chloride (NH Cl) and heat to boiling. standard, g, and
Add a slight excess of ammonium hydroxide (NH OH) and let B =K Fe(CN) solution required for titration of the blank,
2 4 6
standafewminutestoallowanyprecipitatetocoagulate.Filter mL.
through an ashless, rapid paper into a 400-mL beaker and
16.3 Thymol Blue Indicator Solution (0.5 g/L)—Dissolve
wash.
0.1 g of thymol blue indicator in 200-mLof methanol, ethanol,
15.2 Heatthefiltratetoboilingandadd5mLofNH OH(sp or isopropanol.
gr 0.90). Add dropwise 10 mL of the acetone solution of
16.4 Uranyl Acetate Indicator Solution (50 g/L)—Dissolve
8-hydroxyquinoline (Note 6). Let stand 10 to 20 min and filter
5gofUO (C H O ) ·H O in water made slightly acid with
2 2 3 2 2 2
through a medium-porosity sintered-glass crucible. Wash well
acetic acid and dilute to 100 mL.
with water.
17. Procedure
NOTE 6—The reagent is used in acetone solution rather than alcohol
solution to eliminate the danger of reducing some of the chromate by
17.1 Pipet50mLofthesolutionofthespecimen(Section9)
alcohol. Avoid adding an excess of reagent and lengthy boiling after its
into a 400-mL beaker. Add 35 mL of H SO (1+5) and 3 to 4
2 4
addition. Ten millilitres of hydroxyquinoline (50 g/L) is sufficient for a
drops of thymol blue indicator solution. First add NH OH (sp
normal zinc yellow. The solution can be tested for complete precipitation,
gr 0.90) and finally NH OH (1+10) until the color of the
but since the reagent itself is rather insoluble, the results may be 4
misleading. The insoluble reagent will dissolve in a hot solution and also indicator changes to a salmon shade intermediate between pink
in an excess of alcohol or acetone, whereas the zinc oxyquinolate will not.
and yellow.This gives a pH of about 2.4. Dilute the solution to
300 mL and heat to just under boiling. Pass in HSata
15.3 Dry the precipitate at 165°C for at least 2 h and weigh
moderate rate for 40 min. Allow the precipitate to settle for 1
as zinc oxyquinolate.
h and filter. Wash the filter ten times with water saturated with
15.4 Calculation—Calculate the percent zinc A as zinc
hydrogen sulfide gas (H S).
oxide (ZnO), as follows:
17.2 Dissolve the precipitate in hot HCl (1+3) and wash the
A 5 @ P 30.2303 /S # 3100
~ !
filter paper well with hot water. Boil out the H S, neutralize to
where:
methyl orange with NH OH, and dilute to 300 mL.Add2gof
NH Cl and 3 mL of HCl (sp gr 1.19), and heat to boiling.
P = zinc oxyquinolate, g, and
S = specimen in aliquot used, g.
17.3 Titrate the hot solution with K Fe(CN) solution
4 6
0.2303 = ZnO/zinc oxyquinolate = 81.38⁄353.37
(16.2), using uranyl acetate as an external indicator on a spot
plate or 1 to 2 drops of ferrous ammonium sulfate solution as
ZINC BY THE FERROCYANIDE TEST METHOD
an internal indicator.
16. Reagents
17.4 Calculation—Calculate the percent zinc A as ZnO, as
follows:
16.1 Methyl Orange Indicator Solution—Dissolve 0.1 g of
methyl orange in 100 mL of water. A 5 V Z/S 3100
~ !
4 4
D444 − 88 (2008)
where: SULFATES
V =K Fe(CN) solution required for titration of the
4 4 6
20. Reagent
specimen, mL,
Z = ZnO equivalent of the K Fe(CN) solution, g/mL, and 20.1 Barium Chloride Solution (100 g/L)—Dissolve 117 g
4 6
S = specimen in the aliquot used,
...
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