ASTM D3718-85a(1999)

Standard Test Method for Low Concentrations of Chromium in Paint by Atomic Absorption Spectroscopy

SCOPE
1.1 This test method covers the determination of the content of chromium (including chromium oxide) in the range between 0.005 and 1.0% present in the solids of liquid coatings or in dried films obtained from previously coated substrates. There is no reason to believe that higher levels could not be determined by this test method, provided that appropriate dilutions and adjustments in specimen size and reagent quantities are made.  
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7.

General Information

• Status: Historical
• Publication Date: 09-May-1999
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.21 - Chemical Analysis of Paints and Paint Materials

Relations

• Replaced By: ASTM D3718-85a(2005) - Standard Test Method for Low Concentrations of Chromium in Paint by Atomic Absorption Spectroscopy
• Effective Date: 01-Jan-2005
• Referred By: ASTM F2097-20 - Standard Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products
• Effective Date: 10-May-1999

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D3718–85a (Reapproved 1999)
Standard Test Method for
Low Concentrations of Chromium in Paint by Atomic
Absorption Spectroscopy
This standard is issued under the fixed designation D 3718; 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.
1. Scope 5. Apparatus
5.1 Atomic Absorption Spectrophotometer, consisting of an
1.1 This test method covers the determination of the content
of chromium (including chromium oxide) in the range between atomizer and either a single- or three-slot burner; gas pressure-
0.005 and 1.0 % present in the solids of liquid coatings or in regulating and metering devices for nitrous oxide (N O) and
dried films obtained from previously coated substrates. There acetylene; a chromium hollow cathode lamp with a regulated
is no reason to believe that higher levels could not be constant current supply; a monochromator and associated
determined by this test method, provided that appropriate optics; a photosensitive detector connected to an electronic
dilutions and adjustments in specimen size and reagent quan- amplifier; and a readout device.
tities are made. 5.2 Muffle Furnace, maintained at 500 6 10°C.
1.2 This standard does not purport to address all of the 5.3 Force-Draft Oven, maintained at 105 6 2°C.
safety concerns, if any, associated with its use. It is the 5.4 Acid Decomposition Vessel, with PTFE digestion cup.
responsibility of the user of this standard to establish appro- 5.5 Hot Plate, with variable surface temperature control
priate safety and health practices and determine the applica- over the range from 70 to 200°C.
bility of regulatory limitations prior to use. Specific hazard- 5.6 Volumetric Flasks, 50, 100 and 1000-mL.
statements are given in Section 7. 5.7 Pipets, 5, 10, 15, and 20-mL capacity.
5.8 Filter Paper, ashless, medium filtering 15-cm.
2. Referenced Documents
5.9 Paint Shaker.
2.1 ASTM Standards: 5.10 Crucibles, wide form, porcelain, approximately 30-mL
D 1193 Specification for Reagent Water
capacity.
D 2832 Guide for Determining Volatile and Nonvolatile 5.11 Mortar and Pestle.
Content of Paint and Related Coatings
5.12 Paint Draw-Down Bar.
3. Summary of Test Method
6. Reagents
3.1 The sample of liquid coating or dried film is prepared 6.1 Purity of Reagents—Reagent grade chemicals shall be
for analysis by dry ashing at 500°C followed by digestion with
used in all tests. Unless otherwise indicated, it is intended that
potassium permanganate and sulfuric acid in a polytetrafluo- all reagents shall conform to the specifications of the Commit-
roethylene (PTFE)-lined acid decomposition vessel at an
tee onAnalytical Reagents of theAmerican Chemical Society,
elevated temperature. The chromium in the filtered digestion where such specifications are available. Other grades may be
mixture is determined by atomic absorption spectroscopy.
4. Significance and Use
The sole source of supply of an acid decomposition cup, (Catalog Number
4.1 The permissible level of heavy metals in certain coat-
4745), known to the committee at this time is the Parr Instrument Co., 211
ingsisspecifiedbygovernmentalregulatoryagencies.Thistest
Fifty-third St., Moline, IL 61265. If you are aware of alternative suppliers, please
methodprovidesafullydocumentedprocedurefordetermining
provide this information to ASTM Headquarters. Your comments will receive
careful consideration at a meeting of the responsible technical committee, which
low concentrations of chromium present in both water- and
you may attend.
solvent-reducible coatings to determine compliance.
The sole source of supply of No. 25007 crucibles, known to the committee at
this time is Coors Co. If you are aware of alternative suppliers, please provide this
information to ASTM Headquarters. Your comments will receive careful consider-
1 1
This test method is under the jurisdiction of ASTM Committee D-1 on Paint ation at a meeting of the responsible technical committee, which you may attend.
and Related Coatings, Materials, andApplications and is the direct responsibility of Reagent Chemicals, American Chemical Society Specifications, American
Subcommittee D01.21 on Chemical Analysis of Paints and Paint Materials. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Current edition approved May 31 and Nov. 29, 1985. Published January 1986. listed by the American Chemical Society, see Analar Standards for Laboratory
Originally published as D 3718 – 78. Last previous edition D 3718 – 84. Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Annual Book of ASTM Standards, Vol 11.01. and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
Annual Book of ASTM Standards, Vol 06.01. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3718
used, provided it is first ascertained that the reagent is of 8.4 Aspirate water to rinse the atomizer chamber.Aspirate a
sufficiently high purity to permit its use without lessening the standard solution and make any necessary readjustment in
accuracy of the determination. instrumentparameterstoobtainmaximumabsorption.Zerothe
6.2 Purity of Water—Unless otherwise indicated, references instrument while aspirating reagent blank solution (6.7).Aspi-
to water shall be understood to mean reagent water conforming rate each of the appropriate standard solutions and record the
to Type II of Specification D 1193. corresponding instrument readings. Aspirate water between
6.3 Chromium Standard Stock Solution (1 mg/mL)— each standard.
Dissolve 3.735 g of potassium chromate (K CrO ) in 100 mL 8.5 Transfer a 25-mL aliquot from each of the standard
2 4
of water and dilute to 1 L. solutions prepared in 8.1 to 50-mLvolumetric flasks and dilute
6.4 Chromium Standard Working Solution (0.1 mg/mL)— to volume with water. Repeat the steps outlined in 8.4 for the
Pipet 10 mL of the chromium standard stock solution into a diluted aliquot solutions.
100-mL volumetric flask and dilute to volume with water. 8.6 Construct a calibration curve on linear graph paper by
6.5 Oxidizing Solution—Dissolve 0.2 g of potassium per- plotting the absorbance versus concentration (micrograms per
manganate (KMnO ) in 100 mL of H SO (1 + 1). Stir until millilitre) for each set of standard solutions.
4 2 4
completely dissolved. The color of this solution is dark brown.
NOTE 1—To obtain maximum accuracy one should complete calibra-
6.6 Reducing Solution—Dissolve1gof hydroxylamine
tion and standardization just prior to sample analysis.
hydrochloride (NH OH·HCl) in 100 mL of water.
6.7 Reagent Blank—Pipet 5 mL of oxidizing solution into
9. Procedure
25 mL of water contained in a 50-mL volumetric flask. Add
9.1 If the sample is a liquid coating, mix it until homoge-
reducing solution dropwise until the permanganate color has
neous, preferably on a mechanical paint shaker. Determine the
been discharged; then dilute to 50 mL with water.
nonvolatile content in accordance with Guide D 2832.
6.8 Sulfuric Acid (1 + 1)—Carefully add 1 volume of con-
9.2 Determine the ash content of the material under test in
centrated H SO (sp gr 1.84) to 1 volume of water.
2 4
duplicate.
6.9 Sulfuric Acid (5 % volume per volume)—Carefully add
9.2.1 Weigh to the nearest 0.1 mg approximately5gof
50 mL of concentrated H SO (sp gr 1.84) to 500 mL of water
2 4
liquid coating or3gof dried film into each of two tared
and dilute to 1 L.
porcelain crucibles.
7. Hazards
NOTE 2—Recover dried paint films from previously coated substrates
(being careful not to remove any underlying material from the substrate)
7.1 Use care in handling concentrated H SO because it is
2 4
or prepare in the laboratory from liquid samples. For the laboratory
corrosiveandmay
...