ASTM_D_3792_-_16.pdf

Designation:D379216Standard Test Method forWater Content of Coatings by Direct Injection Into a GasChromatograph1This standard is issued under the fixed designation D3792;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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 is for the determination of the totalwater content of waterborne paints.It has been evaluated forlatex systems(styrene-butadiene,poly(vinylacetate)-acrylic,acrylic),epoxy acrylic resin systems and acrylic systems.Theestablished working range of this test method is from 15 to90%.There is no reason to believe that it will not work outsideof this range.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 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 and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)33.Summary of Test Method3.1 A suitable aliquot of whole paint is internallystandardized,diluted with dimethylformamide,and then in-jected into a gas chromatographic column containing a porouspolymer packing that separates water from other volatilecomponents.4.Significance and Use4.1 In order to calculate volatile organic content(VOC)inwaterborne paints,it is necessary to know the water content.This gas chromatographic test method provides a relativelysimple and direct way to determine water content.5.Apparatus5.1 Gas ChromatographyAny gas-liquid chromato-graphic instrument equipped with a thermoconductivity detec-tor may be used.Temperature programming capability ispreferable,but isothermal operations may be adequate.SeeTable 1.5.2 ColumnThe column should be at least 1.22 m(4 ft)of3.2-mm(18-in.)outside diameter tubing of stainless steel,orother suitable material,lined with a TFE-fluorocarbon coatingpacked with 60/80 mesh(180 to 250 m)porous polymerpacking material.4A longer 1.83 m(6-ft)column can be usedto improve resolution.5.3 IntegratorAny electronic integrator that can accu-rately quantify a gas chromatographic peak is acceptable.Alternatively,a recording potentiometer with a full-scaledeflection of 1-10mV,full scale response time of 2 s or less andsufficient sensitivity and stability to meet the requirements of5.1.5.4 Liquid Charging DevicesMicro syringes of 510-Lcapacity with a precision of 60.01 L.Automatic injection ofsamples improves the precision of this test method.6.Column Conditioning6.1 ProcedureInstall the packed column in the gas chro-matographic unit leaving the exit end disconnected from thedetector.This will prevent any contamination of the detectorwith the column bleed.6.1.1 Set the carrier gas flow rate at 20 to 30 mL/min if a3.2-mm(18-in.)outside diameter column is used.Purge thecolumn 5 or 10 min before heating.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 approved April 1,2016.Published May 2016.Originallyapproved in 1979.Last previous edition approved in 2015 as D3792 05(2015).DOI:10.1520/D3792-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4HayeSep R(silanized),was used in the round robin.Any other porous polymerpacking or other column giving equivalent or superior performance may be used.These products are available from most gas chromatography suppliers and distribu-tors.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.1.2 Heat the column from room temperature to 200C at5C/min and hold this temperature for at least 12 h(overnight).At the end of this time,heat the column at 5C/min to 250C(the maximum temperature for this packing)and hold forseveral hours.Cool the column to room temperature andconnect to the detector.6.1.3 Reheat the column to 250C at 5C/min to observe ifthere is column bleed.Optimum conditioning of this columnmay take several cycles of the heating program before a flatrecorder baseline is achieved.6.2 Before each cal