1、Designation:D371885a(Reapproved 2022)1Standard Test Method forLow Concentrations of Chromium in Paint by AtomicAbsorption Spectroscopy1This standard is issued under the fixed designation D3718;the number immediately following the designation indicates the year oforiginal adoption or,in the case of r
2、evision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript 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.1NOTEFootnote 4 was updated e
3、ditorially in June 2022.1.Scope1.1 This test method covers the determination of the contentof chromium(including chromium oxide)in the range between0.005 and 1.0%present in the solids of liquid coatings or indried films obtained from previously coated substrates.Thereis no reason to believe that hig
4、her levels could not bedetermined by this test method,provided that appropriatedilutions and adjustments in specimen size and reagent quan-tities are made.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does
5、 not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific hazard statements
6、 are given in Section 7.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organizati
7、on TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD2832 Guide for Determining Volatile and Nonvolatile Con-tent of Paint and Related Coatings3.Summary of Test Method3.1 The sample of liquid coating or dried film is preparedfor
8、analysis by dry ashing at 500 C followed by digestion withpotassium permanganate and sulfuric acid in a polytetrafluo-roethylene(PTFE)-lined acid decomposition vessel at anelevated temperature.The chromium in the filtered digestionmixture is determined by atomic absorption spectroscopy.4.Significanc
9、e and Use4.1 The permissible level of heavy metals in certain coat-ings is specified by governmental regulatory agencies.This testmethod provides a fully documented procedure for determininglow concentrations of chromium present in both water-andsolvent-reducible coatings to determine compliance.5.A
10、pparatus5.1 Atomic Absorption Spectrophotometer,consisting of anatomizer and either a single-or three-slot burner;gas pressure-regulating and metering devices for nitrous oxide(N2O)andacetylene;a chromium hollow cathode lamp with a regulatedconstant current supply;a monochromator and associatedoptic
11、s;a photosensitive detector connected to an electronicamplifier;and a readout device.5.2 Muffle Furnace,maintained at 500 6 10 C.5.3 Force-Draft Oven,maintained at 105 6 2 C.5.4 Acid Decomposition Vessel,with PTFE digestion cup.35.5 Hot Plate,with variable surface temperature controlover the range f
12、rom 70 to 200 C.5.6 Volumetric Flasks,50,100,and 1000-mL.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition
13、 approved June 1,2022.Published July 2022.Originally approvedin 1978.Last previous edition approved in 2015 as D3718 85a(2015).DOI:10.1520/D3718-85AR22E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStan
14、dards volume information,refer to the standards Document Summary page onthe ASTM website.3The sole source of supply of an acid decomposition cup,(Catalog Number4745),known to the committee at this time is the Parr Instrument Co.,211Fifty-third St.,Moline,IL 61265.If you are aware of alternative supp
15、liers,pleaseprovide this information to ASTM International Headquarters.Your comments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United Stat
16、esThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.15.7 Pipets,5,10,15,and 20-mL capacity.5.8 Filter Paper,ashless,medium filtering 15-cm.5.9 Paint Shaker.5.10 Crucibles,wide form,porcelain,approximately 30-mLcapacity.45.11 Mortar and
