ASTM D126-87(2023)
(Test Method)Standard Test Methods for Analysis of Yellow, Orange, and Green Pigments Containing Lead Chromate and Chromium Oxide Green
Standard Test Methods for Analysis of Yellow, Orange, and Green Pigments Containing Lead Chromate and Chromium Oxide Green
SIGNIFICANCE AND USE
4.1 These test methods are for analysis designed as an aid in quality of yellow, orange, and green pigments containing lead chromate and chromium oxide green. Some sections may be applicable to analysis of these pigments when extracted from whole paints.
SCOPE
1.1 These test methods cover procedures for the chemical analysis of yellow, orange, and green pigments containing lead chromate and chromium oxide green.
1.2 The analytical procedures appear in the following order:
Sections
Chrome Yellow, Chrome Orange, and Molybdate Orange
Organic Colors and Lakes
7
Moisture and Other Volatile Matter
8
Matter Soluble in Water
9
Lead Chromate
10 and 11
Total Lead
12
Sulfate
13 and 14
Carbon Dioxide
15
Molybdenum
16 and 17
Extenders
18 – 22
Calculation of Substances Other than Insoluble Lead
Compounds
23 and 24
Pure Chrome Green and Reduced Chrome Green
Organic Colors and Lakes
25
Moisture and Other Volatile Matter
26
Matter Soluble in Water
27
Iron Blue
28
Lead Chromate
29 and 30
Barium Sulfate and Insoluble Siliceous Material
31
Total Lead
32
Sulfate
33
Calcium Oxide Soluble in Acid
34 and 35
Extenders
36
Calculation of Insoluble Lead Compounds
37
Chromium Oxide Green
Organic Colors and Lakes
38
Moisture and Other Volatile Matter
39
Matter Soluble in Water
40
Total Chromium as Chromium Oxide
41
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety problems, 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. Specific hazard statements are given in Note 3.
1.5 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
Relations
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: D126 − 87 (Reapproved 2023)
Standard Test Methods for
Analysis of Yellow, Orange, and Green Pigments Containing
Lead Chromate and Chromium Oxide Green
This standard is issued under the fixed designation D126; 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 responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 These test methods cover procedures for the chemical
mine the applicability of regulatory limitations prior to use.
analysis of yellow, orange, and green pigments containing lead
Specific hazard statements are given in Note 3.
chromate and chromium oxide green.
1.5 This international standard was developed in accor-
1.2 The analytical procedures appear in the following order:
dance with internationally recognized principles on standard-
Sections
ization established in the Decision on Principles for the
CHROME YELLOW, CHROME ORANGE, AND MOLYBDATE ORANGE
Development of International Standards, Guides and Recom-
Organic Colors and Lakes 7
Moisture and Other Volatile Matter 8 mendations issued by the World Trade Organization Technical
Matter Soluble in Water 9
Barriers to Trade (TBT) Committee.
Lead Chromate 10 and 11
Total Lead 12
Sulfate 13 and 14
2. Referenced Documents
Carbon Dioxide 15
Molybdenum 16 and 17 2.1 ASTM Standards:
Extenders 18 – 22
D280 Test Methods for Hygroscopic Moisture (and Other
Calculation of Substances Other than Insoluble Lead
Matter Volatile Under the Test Conditions) in Pigments
Compounds 23 and 24
PURE CHROME GREEN AND REDUCED CHROME GREEN D521 Test Methods for Chemical Analysis of Zinc Dust
Organic Colors and Lakes 25
(Metallic Zinc Powder)
Moisture and Other Volatile Matter 26
D1013 Test Method for Determining Total Nitrogen in
Matter Soluble in Water 27
Iron Blue 28 Resins and Plastics (Withdrawn 2007)
Lead Chromate 29 and 30
D1193 Specification for Reagent Water
Barium Sulfate and Insoluble Siliceous Material 31
E11 Specification for Woven Wire Test Sieve Cloth and Test
Total Lead 32
Sulfate 33 Sieves
Calcium Oxide Soluble in Acid 34 and 35
Extenders 36
3. Summary of Test Methods
Calculation of Insoluble Lead Compounds
3.1 Chrome Yellow, Chrome Orange, and Molybdate Or-
CHROMIUM OXIDE GREEN
Organic Colors and Lakes 38
ange:
Moisture and Other Volatile Matter 39
3.1.1 Organic colors and lakes are determined qualitatively
Matter Soluble in Water 40
by boiling the sample in water, then ethyl alcohol, and finally
Total Chromium as Chromium Oxide 41
chloroform.
1.3 The values stated in SI units are to be regarded as
3.1.2 Moisture and other volatile matter are determined in
standard. No other units of measurement are included in this
accordance with Test Method A of Test Methods D280.
standard.
3.1.3 Matter soluble in water is determined by boiling in
1.4 This standard does not purport to address all of the
water and filtering.
safety problems, if any, associated with its use. It is the
1 2
These test methods are under the jurisdiction of ASTM Committee D01 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Paint and Related Coatings, Materials, and Applications and are the direct contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
responsibility of Subcommittee D01.31 on Pigment Specifications. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved June 1, 2023. Published June 2023. Originally the ASTM website.
approved in 1922. Last previous edition approved in 2019 as D126 – 87 (2019). The last approved version of this historical standard is referenced on
DOI: 10.1520/D0126-87R23. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D126 − 87 (2023)
3.1.4 Lead chromate is determined by dissolving the sample 5. Purity of Reagents and Water
in dilute HCl, filtering and titrating potentiometrically with
5.1 Reagents—Unless otherwise indicated, it is intended
FeSO solution after addition of HClO .
4 4
that all reagents shall conform to the specifications of the
3.1.5 Total lead is determined by precipitation as lead
Committee on Analytical Reagents of the American Chemical
sulfide solution with H SO and final precipitation as lead
2 4
Society, where such specifications are available. Other grades
sulfate.
may be used, provided it is first ascertained that the reagent is
3.1.6 Sulfate is determined by dissolving the sample in
of sufficiently high purity to permit its use without lessening
acetic acid, neutralizing with sodium carbonate, plus addition
the accuracy of the determination.
of HCl to an aliquot followed by addition of BaCl to
precipitate as barium sulfate.
5.2 Water—Unless otherwise indicated, references to water
3.1.7 Carbon dioxide is determined by evolution.
for use in the preparation of reagents and in analytical
3.1.8 Molybdenum is determined by precipitation as the
procedures shall be understood to mean reagent water con-
sulfide, solution in HNO and H SO , addition of NH OH and
3 2 4 4
forming to Type II of Specification D1193.
H SO . The solution is reduced in a Jones reductor, collected
2 4
under Fe (SO ) solution and titrated with KMnO solution.
2 4 3 4
6. Preparation of Sample
3.1.9 Extenders are either:
6.1 Mix the sample thoroughly and take a representative
3.1.9.1 Calcium carbonate, calcium sulfate, magnesium car-
portion for analysis. Reduce any lumps or coarse particles to a
bonate or;
fine powder by grinding. Grind extracted pigments to pass a
(a) The compounds in 3.1.9.1 are determined qualitatively
No. 80 (180 μm) sieve (Note 1). Discard any skins that do not
by precipitation with ammonium solution.
pass through the sieve. Thoroughly mix the finely ground
(b) If chromium is present, it is reduced and the lead salts
dissolved in dissolving solution. Hydroxides and hydrous pigment and preserve in stoppered and suitably identified
bottles or containers.
oxides are precipitated by addition of HCl and NH OH and
filtered. CaC O is precipitated with calcium oxalate solution
2 4
NOTE 1—Detailed requirements for this sieve are given in Specification
and filtered, ashed and weighed as CaO. Alternatively, the
E11.
precipitate is dissolved in H SO and titrated with KMnO .
2 4 4
6.2 Moisten the weighed portions of extracted pigments
Magnesium is determined on the filtrate from calcium deter-
with a small amount of suitable wetting agent (Note 1) before
mination by precipitation as the phosphate with ammonium
adding reagents for analysis.
phosphate solution.
3.2 Chromium Oxide Green:
NOTE 2—A 0.1 % solution of sodium dioctylsuccinosulfonate has been
3.2.1 Organic colors and lakes are determined qualitatively found satisfactory. (This material is sold under the trade name of Aerosol
OT.) Wetting agents containing mineral salts, sulfates, or sulfonates which
by boiling the sample in water, then ethyl alcohol, and finally
may be hydrolyzed to sulfates, should be avoided; the use of alcohol is
choloroform.
also undesirable because of its tendency to reduce chromates.
3.2.2 Moisture and other volatile matter are determined in
NOTE 3—Warning: As the National Institute for Occupational Safety
accordance with Test Method A of Test Methods D280.
and Health has stated that hexavalent chromium compounds are hazardous
3.2.3 Matter soluble in water is determined by boiling in
to health, care should be exercised in preparation of the sample. The
water and filtering.
wearing of a respirator and rubber or synthetic gloves are recommended.
3.2.4 Total chromium as chromium oxide is determined by If hexavalent chromium materials come in contact with the skin, wash
thoroughly with soap and water.
dissolving the sample in dilute HCl, filtering and titrating
potentiometrically with FeSO solution after addition of
HClO .
4. Significance and Use
4.1 These test methods are for analysis designed as an aid in
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
quality of yellow, orange, and green pigments containing lead
DC. For suggestions on the testing of reagents not listed by the American Chemical
chromate and chromium oxide green. Some sections may be
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
applicable to analysis of these pigments when extracted from
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
whole paints. copeial Convention, Inc. (USPC), Rockville, MD.
CHROME YELLOW, CHROME ORANGE, AND MOLYBDATE ORANGE
(Primrose, Lemon, and Medium Yellows; Chrome Oranges; Lead Molybdate or Basic Lead Chromate; Molybdate Orange)
ORGANIC COLORS AND LAKES residue with 25 mL of ethyl alcohol (absolute or 95 %) and
decant as before. Likewise boil with 25 mL of chloroform and
7. Procedure
again decant. If any one of the above solutions is colored,
7.1 Boil 2 g of the sample 2 min with 25 mL of water, let organic colors are present. If all solutions remain colorless,
settle, and decant the supernatant liquid. Similarly, boil the organic colors are presumably absent. The presence of organic
D126 − 87 (2023)
hydroxide or hydrofluoric acid.
colors resistant to the above reagents is unlikely, but may be
Also, if trivalent antimony has been used in manufacturing the product,
tested for by reference to procedures given in standard refer-
pentavalent antimony may be present which would interfere in the
ence works.
determination of lead chromate.
11.2 Alternatively, the solution may be reduced by a known
MOISTURE AND OTHER VOLATILE MATTER
excess of FeSO solution and back-titrated with KMnO
4 4
8. Procedure
solution in the presence of MnSO , or excess KI may be added
and the liberated iodine titrated with Na S O solution, using
8.1 Determine moisture and other volatile matter in accor-
2 2 3
starch indicator. The iodine liberation method is not applicable
dance with Test Method A of Test Methods D280.
in the presence of molybdenum.
MATTER SOLUBLE IN WATER
TOTAL LEAD
9. Procedure
12. Procedure
9.1 Place 2.5 g of the sample in a graduated 250 mL flask.
Add 100 mL of water and boil for 5 min. Cool, dilute to exactly
12.1 Dissolve 0.5 g of sample as described in Section 11.
250 mL, mix, and allow to settle. Filter the supernatant liquid
Add 5 mL of ethyl alcohol (95 % or absolute) and boil until the
through a dry paper and discard the first 20 mL. Evaporate
chromium is reduced, as indicated by a green color. Filter if
100 mL of the clear filtrate to dryness in a weighed dish, heat
any insoluble residue is present, retaining the filtrate and
for 1 h at 105 °C to 110 °C, cool, and weigh.
washings for the determination. Add NH OH (sp gr 0.90) to
this solution until a faint precipitate begins to form; then add
9.2 Calculation—Calculate the % of matter soluble in water
5 mL of HCl (sp gr 1.19) slowly, dilute to 500 mL, and pass a
as follows:
rapid current of H S into the solution until precipitation is
Matter soluble in water, % 5 R × 2.5 × 100 /S (1)
~ !
complete. Settle, filter, and wash with water containing H S.
where:
12.2 Rinse the precipitate from the filter (Note 5) into a
R = weight of residue, and
beaker containing 25 mL of HNO (1+3) and boil until all PbS
S = specimen weight, g.
has dissolved. Add 10 mL of H SO (1+1) and evaporate to
2 4
strong fumes of SO . Cool and add 50 mL of water and 50 mL
6 3
LEAD CHROMATE
of ethyl alcohol (95 %) (Note 6). Let stand 1 h; then filter on
a tarred Gooch crucible. Wash with ethyl alcohol (95 %), dry,
10. Reagents
ignite at 500 °C to 600 °C, and weigh as PbSO .
10.1 Dissolving Solution—Saturate 1 L of water with NaCl.
NOTE 5—If a trace of sulfide remains on the paper, the stained portion
Filter. Add to the filtered solution 150 mL of water and 100 mL
of the paper may be separately treated with bromine water, the paper
of HCl (sp gr 1.19).
filtered off, and the filtrate added to the body of the solution.
NOTE 6—Any sulfur remaining from decomposition of the sulfides may
10.2 Ferrous Sulfate, Standard Solution (0.3 N)—Dissolve
be mechanically removed as a globule of solidified sulfur at this point.
86 g of FeSO · 7H O in 500 mL of water to which 30 mL of
4 2
H SO (sp gr 1.84) has been added with constant stirring. 6
2 4
SULFATE
Dilute to 1 L and standardize not more than 6 h before use by
potentiometric titration against 0.7 g portions of K Cr O .
2 2 7
13. Reagents
11. Procedure 13.1 Barium Chloride Solution—Dissolve 117 g of BaCl ·
2H O in water and dilute to 1 L.
11.1 Dissolve 1 g of the sample in 150 mL of the dissolving
solution. Agitate for 10 min to 15 min, keeping the solution 13.2 Dissolving Solution—See 10.1.
cold until dissolution is complete (Note 4). If dissolution is not
13.3 Sodium Carbonate Solution (saturated)—Prepare a
complete, filter through fine grade filter paper and wash with
solution containing excess Na CO at laboratory temperature,
2 3
three 10 mL portions of cold dissolving solution. Add 10 mL of
and free of SO . Decant the clear solution for use as required.
HClO (70 %), dilute to 250 mL, and titrate potentiometrically
with FeSO solution.
4 14. Procedure
NOTE 4—Incomplete solution of the pigment is evidence of the possible
14.1 Digest 1.25 g of the sample with 100 mL of dissolving
presence of barium sulfate, silica, silicates, or other acid-insoluble
solution at 100 °C for 5 min. Add 25 mL of glacial acetic acid
extenders (see Section 18). Some chrome yellows may contain organic
and 15 mL of ethyl alcohol and heat gently for 10 min to
addition agents and will give a turbid solution at this point.
reduce chromium, as indicated by the green color of the
Newer chemically resistant-type lead chromate type pigments (silica
encapsulated) cannot be decomposed by the procedures described in this solution. Cool. Neutralize with saturated Na CO solution and
2 3
method. Pigments of this type may require treatment with strong alkali
add a slight excess. Transfer to a 250 mL volumetric flask,
dilute to the mark with distilled water, and mix. Filter without
washing through a dry filter paper, discarding the first 10 mL to
Reference may be made to the following: Payne, H.
...
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