ASTM D126-87(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D126–87(Reapproved2002)
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.Anumber 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.
1. Scope 2. Referenced Documents
1.1 These test methods cover procedures for the chemical 2.1 ASTM Standards:
analysisofyellow,orange,andgreenpigmentscontaininglead D280 Test Methods for Hygroscopic Moisture (and Other
chromate and chromium oxide green. Matter Volatile Under the Test Conditions) in Pigments
1.2 Theanalyticalproceduresappearinthefollowingorder: D521 Test Methods for Chemical Analysis of Zinc Dust
(Metallic Zinc Powder)
Sections
CHROME YELLOW,CHROME ORANGE, AND MOLYBDATE ORANGE
D1013 Test Method for Determining Total Nitrogen in
Organic Colors and Lakes 7
Resins and Plastics
Moisture and Other Volatile Matter 8
D1193 Specification for Reagent Water
Matter Soluble in Water 9
Lead Chromate 10 and 11
E11 Specification for Wire Cloth Sieves for Testing Pur-
Total Lead 12
poses
Sulfate 13 and 14
Carbon Dioxide 15
3. Summary of Test Methods
Molybdenum 16 and 17
Extenders 18-22
3.1 Chrome Yellow, Chrome Orange, and Molybdate Or-
Calculation of Substances Other than Insoluble Lead
ange:
Compounds 23 and 24
PURE CHROME GREEN AND REDUCED CHROME GREEN
3.1.1 Organic colors and lakes are determined qualitatively
Organic Colors and Lakes 25
by boiling the sample in water, then ethyl alcohol, and finally
Moisture and Other Volatile Matter 26
Matter Soluble in Water 27 chloroform.
Iron Blue 28
3.1.2 Moisture and other volatile matter are determined in
Lead Chromate 29 and 30
accordance with Test Method A of Test Methods D280.
Barium Sulfate and Insoluble Siliceous Material 31
Total Lead 32 3.1.3 Matter soluble in water is determined by boiling in
Sulfate 33
water and filtering.
Calcium Oxide Soluble in Acid 34 and 35
3.1.4 Leadchromateisdeterminedbydissolvingthesample
Extenders 36
in dilute HCl, filtering and titrating potentiometrically with
Calculation of Insoluble Lead Com-
pounds 37
FeSO solution after addition of HClO .
4 4
CHROMIUM OXIDE GREEN
3.1.5 Total lead is determined by precipitation as lead
Organic Colors and Lakes 38
Moisture and Other Volatile Matter 39 sulfide solution with H SO and final precipitation as lead
2 4
Matter Soluble in Water 40
sulfate.
Total Chromium as Chromium Oxide 41
3.1.6 Sulfate is determined by dissolving the sample in
1.3 This standard does not purport to address all of the
acetic acid, neutralizing with sodium carbonate, plus addition
safety problems, if any, associated with its use. It is the
of HCl to an aliquot followed by addition of BaCl to
responsibility of the user of this standard to establish appro-
precipitate as barium sulfate.
priate safety and health practices and determine the applica-
3.1.7 Carbon dioxide is determined by evolution.
bility of regulatory limitations prior to use. Specific hazard
3.1.8 Molybdenum is determined by precipitation as the
statements are given in Note 3.
sulfide, solution in HNO and H SO , addition of NH OH and
3 2 4 4
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
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. Annual Book of ASTM Standards, Vol 06.03.
Current edition approved May 29, 1987. Published July 1987. Originally Annual Book of ASTM Standards, Vol 11.01.
e1 4
published as D126–22. Last previous edition D126–65(1981) . Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D126
3.1.9 Extenders are either: Society, where such specifications are available. Other grades
3.1.9.1 Calciumcarbonate,calciumsulfate,magnesiumcar- may be used, provided it is first ascertained that the reagent is
bonate or; of sufficiently high purity to permit its use without lessening
(a) (a) The compounds in 3.1.9.1 are determined qualita- the accuracy of the determination.
tively by precipitation with ammonium solution. 5.2 Water—Unless otherwise indicated, references to water
(b) (b) If chromium is present, it is reduced and the lead for use in the preparation of reagents and in analytical
salts dissolved in dissolving solution. Hydroxides and hydrous procedures shall be understood to mean reagent water con-
oxides are precipitated by addition of HCl and NH OH and forming to Type II of Specification D1193.
filtered. CaC O is precipitated with calcium oxalate solution
2 4
6. Preparation of Sample
and filtered, ashed and weighed as CaO. Alternatively, the
6.1 Mix the sample thoroughly and take a representative
precipitate is dissolved in H SO and titrated with KMnO .
2 4 4
portion for analysis. Reduce any lumps or coarse particles to a
Magnesium is determined on the filtrate from calcium deter-
fine powder by grinding. Grind extracted pigments to pass a
mination by precipitation as the phosphate with ammonium
No. 80 (180-µm) sieve (Note 1). Discard any skins that do not
phosphate solution.
pass through the sieve. Thoroughly mix the finely ground
3.2 Chromium Oxide Green:
pigment and preserve in stoppered and suitably identified
3.2.1 Organic colors and lakes are determined qualitatively
bottles or containers.
by boiling the sample in water, then ethyl alcohol, and finally
choloroform.
NOTE 1—DetailedrequirementsforthissievearegiveninSpecification
3.2.2 Moisture and other volatile matter are determined in E11.
accordance with Test Method A of Test Methods D280.
6.2 Moisten the weighed portions of extracted pigments
3.2.3 Matter soluble in water is determined by boiling in
with a small amount of suitable wetting agent (Note 1) before
water and filtering.
adding reagents for analysis.
3.2.4 Total chromium as chromium oxide is determined by
NOTE 2—A0.1% solution of sodium dioctylsuccinosulfonate has been
dissolving the sample in dilute HCl, filtering and titrating
found satisfactory. (This material is sold under the trade name ofAerosol
potentiometrically with FeSO solution after addition of
OT.)Wettingagentscontainingmineralsalts,sulfates,orsulfonateswhich
HClO .
may be hydrolyzed to sulfates, should be avoided; the use of alcohol is
also undesirable because of its tendency to reduce chromates.
NOTE 3—Warning:As the National Institute for Occupational Safety
4. Significance and Use
andHealthhasstatedthathexavalentchromiumcompoundsarehazardous
4.1 Thesetestmethodsareforanalysisdesignedasanaidin
to health, care should be exercised in preparation of the sample. The
quality of yellow, orange, and green pigments containing lead
wearing of a respirator and rubber or synthetic gloves are recommended.
chromate and chromium oxide green. Some sections may be
If hexavalent chromium materials come in contact with the skin, wash
applicable to analysis of these pigments when extracted from thoroughly with soap and water.
whole paints.
Reagent Chemicals, American Chemical Society, Specifications, American
5. Purity of Reagents and Water
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
5.1 Reagents—Unless otherwise indicated, it is intended
Chemicals, BDH, Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
that all reagents shall conform to the specifications of the
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
Committee onAnalytical Reagents of theAmerican Chemical 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 colors resistant to the above reagents is unlikely, but may be
tested for by reference to procedures given in standard refer-
7. Procedure 6
ence works.
7.1 Boil 2 g of the sample 2 min with 25 mL of water, let
settle, and decant the supernatant liquid. Similarly, boil the
residue with 25 mL of ethyl alcohol (absolute or 95%) and
decant as before. Likewise boil with 25 mLof chloroform and
again decant. If any one of the above solutions is colored,
organic colors are present. If all solutions remain colorless,
Reference may be made to the following: Payne, H. F., “Organic Coatings
Technology,” Vol II, John Wiley & Sons, Inc., New York, NY, 1961.
organic colors are presumably absent. The presence of organic
D126
MOISTURE AND OTHER VOLATILE MATTER 11.2 Alternatively, the solution may be reduced by a known
excess of FeSO solution and back-titrated with KMnO
4 4
8. Procedure solutioninthepresenceofMnSO ,orexcessKImaybeadded
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.
12.1 Dissolve 0.5 g of sample as described in Section 11.
Add100mLofwaterandboilfor5min.Cool,dilutetoexactly
Add5mLofethylalcohol(95%orabsolute)andboiluntilthe
250 mL, mix, and allow to settle. Filter the supernatant liquid
chromium is reduced, as indicated by a green color. Filter if
throughadrypaperanddiscardthefirst20mL.Evaporate100
any insoluble residue is present, retaining the filtrate and
mLof the clear filtrate to dryness in a weighed dish, heat for 1
washings for the determination. Add NH OH (sp gr 0.90) to
h at 105 to 110°C, cool, and weigh.
this solution until a faint precipitate begins to form; then add 5
9.2 Calculation—Calculatethe%ofmattersolubleinwater
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
Mattersolubleinwater,% 5 ~R32.5 3100!/S (1)
complete. Settle, filter, and wash with water containing H S.
12.2 Rinse the precipitate from the filter (Note 5) into a
where:
beaker containing 25 mLof HNO (1+3) and boil until all PbS
R = weight of residue, and
has dissolved. Add 10 mL of H SO (1+1) and evaporate to
S = specimen weight, g. 2 4
strong fumes of SO . Cool and add 50 mLof water and 50 mL
of ethyl alcohol (95%) (Note 6). Let stand 1 h; then filter on
LEAD CHROMATE
a tarred Gooch crucible. Wash with ethyl alcohol (95%), dry,
ignite at 500 to 600°C, and weigh as PbSO .
10. Reagents 4
10.1 Dissolving Solution—Saturate 1 Lof water with NaCl. NOTE 5—If a trace of sulfide remains on the paper, the stained portion
of the paper may be separately treated with bromine water, the paper
Filter.Addtothefilteredsolution150mLofwaterand100mL
filtered off, and the filtrate added to the body of the solution.
of HCl (sp gr 1.19).
NOTE 6—Anysulfurremainingfromdecompositionofthesulfidesmay
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.
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 . 13. Reagents
2 2 7
13.1 Barium Chloride Solution—Dissolve 117 g of BaCl ·
11. Procedure
2H O in water and dilute to 1 L.
11.1 Dissolve1gofthesamplein150mLofthedissolving 13.2 Dissolving Solution—See 10.1.
solution. Agitate for 10 to 15 min, keeping the solution cold
13.3 Sodium Carbonate Solution —(saturated)—Prepare a
until dissolution is complete (Note 4). If dissolution is not solution containing excess Na CO at laboratory temperature,
2 3
complete, filter through fine grade filter paper and wash with
and free of SO . Decant the clear solution for use as required.
three10-mLportionsofcolddissolvingsolution.Add10mLof
14. Procedure
HClO (70%), dilute to 250 mL, and titrate potentiometrically
with FeSO solution.
4 14.1 Digest 1.25 g of the sample with 100 mLof dissolving
solution at 100°C for 5 min.Add 25 mL of glacial acetic acid
NOTE 4—Incompletesolutionofthepigmentisevidenceofthepossible
and 15 mL of ethyl alcohol and heat gently for 10 min to
presence of barium sulfate, silica, silicates, or other acid-insoluble
extenders (see Section 18). Some chrome yellows may contain organic reduce chromium, as indicated by the green color of the
addition agents and will give a turbid solution at this point.
solution. Cool. Neutralize with saturated Na CO solution and
2 3
Newer chemically resistant-type lead chromate type pigments (silica
add a slight excess. Transfer to a 250-mL volumetric flask,
encapsulated) cannot be decomposed by the procedures described in this
dilute to the mark with distilled water, and mix. Filter without
method. Pigments of this type may require treatment with strong alkali
washing through a dry filter paper, discarding the first 10 to 15
hydroxide or hydrofluoric acid.
mL.
Also, if trivalent antimony has been used in manufacturing the product,
14.2 Take a 200-mL aliquot of the filtrate, neutralize with
pentavalent antimony may be present which would interfere in the
determination of lead chromate.
HCl (1+1), and add 10 mLexcess. Heat to boiling and boil for
5 min. To the gently boiling solution, add 15 mL of BaCl
solution dropwise with constant stirring. Digest on a steam
bath for 2 h. Filter through an ignited tarred Gooch crucible,
Sections23and24under“CalculationofSubstancesOtherthanInsolubleLead
wash with HCl (1+99), and finally with hot water. Dry at 105
Compounds”shouldbereadcarefullybeforeproceedingwiththeanalysesdescribed
in Sections 10 to 22. to 110°C, ignite at 900°C, and weigh.
D126
CARBON DIOXIDE cover and inside of the beaker and fume again to remove all
HNO . Dilute to 200 mL and add NH OH (1+4) until neutral;
3 4
15. Procedure
then add 10 mL of H SO (sp gr 1.84).
2 4
15.1 DetermineCO bytheevolutionmethodon2.5gofthe 17.3 Cool the solution and reduce by passing through a
Jones reductor at a rate not exceeding 100 mL/min, collecting
sample, using dilute HNO free of NO or NO and absorbing
3 2
the CO in soda lime or i
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