1、Designation:D362485a(Reapproved 2015)Standard Test Method forLow Concentrations of Mercury in Paint by AtomicAbsorption Spectroscopy1This standard is issued under the fixed designation D3624;the number immediately following the designation indicates the year oforiginal adoption or,in the case of rev
2、ision,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.1.Scope1.1 This test method cov
3、ers the determination of the contentof mercury in the range between 10 and 1000 ppm(mg/kg)present in liquid coatings,coatings vehicles,or in dried filmsobtained from previously coated substrates.There is no reasonto believe that higher levels could not be determined by thistest method,provided that
4、appropriate dilutions and adjust-ments in specimen size and reagent quantities are made.1.2 This standard does 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 and health practices an
5、d determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are given in Section 7 and 9.1.1.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent Water3.Summary of Test Method3.1 The sample of liquid coating or dried film is weighedinto a poly
6、tetrafluoroethylene(PTFE)-lined acid decomposi-tion vessel and digested at an elevated temperature usingsulfuric and nitric acids.Use of a sealed acid decompositionvessel prevents loss of mercury during the digestion.Thedigested sample is diluted to a known volume with water andthe concentration of
7、mercury is determined using a cold-vapor,atomic absorption technique.4.Significance 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 mercur
8、y present in both water andsolvent-reducible coatings to determine compliance.5.Apparatus5.1 Atomic Absorption SpectrophotometerAny commer-cial instrument having an open sample presentation area inwhich to mount the absorption cell or an instrument designedspecifically for the measurement of mercury
9、 using the coldvapor technique.5.2 Recorder,0 to 10 mV.5.3 Mercury Source Lamp.5.4 Absorption CellStandard spectrophotometer cells 100mm long,having quartz end windows may be used.Prior touse,the cell must be positioned in the optical path of thespectrophotometer and held in place by suitable clamps
10、 orstraps.The cell should be carefully aligned both vertically andhorizontally to give the maximum transmittance.5.5 Reduction VesselCylindrical gas washing bottle,250-mL,equipped with a coarse(40 to 60-m)fritted glass inlettube and a standard-taper glass stopper.Polyethylene or poly-(vinyl chloride
11、)tubing may be used for connecting the reduc-tion vessel to the absorption cell.5.6 Flowmeter,capable of measuring a gas flow of 1 L/min.5.7 Drying TubeApproximately 150 by 20-mm(6 by34-in.)glass tube filled with magnesium perchlorate.The tubeshould be filled each day that it is in use,and the Mg(Cl
12、O4)2should be replaced whenever it becomes saturated(carefullyobserve after each analysis).NOTE1Use of an indicator desiccant at the exit end of the tube willmake this observation easier.5.8 Water Vapor TrapA second 250-mL gas washingbottle(the same as used for the reduction vessel).If preferred,a 2
13、50-mL Erlenmeyer vacuum flask fitted with a one-holestopper and 200 mm of 5-mm outside diameter glass tubing,may be substituted.(Fig.1)1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommi
14、ttee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1,2015.Published June 2015.Originallyapproved in 1977.Last previous edition approved in 2010 as D3624 85a(2010).DOI:10.1520/D3624-85AR15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orc
15、ontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.9 Mercury TrapA 250-mL E
16、rlenmeyer vacuum flaskcontaining 75 mL of 10%sulfuric acid and 75 mL of 0.1 Npotassium permanganate solution to absorb the mercury vaporafter analysis.5.10 Circulating Oven,maintained at 140 6 5C.5.11 Acid Decomposition Vessel,with 25-mL PTFE diges-tion cup.35.12 Volumetric Flasks,100,250,and 1000-mL.5.13 Paint Shaker.5.14 Paint Draw-Down Bar.6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform