ASTM_D_4628_-_14.pdf

Designation:D462814Standard Test Method forAnalysis of Barium,Calcium,Magnesium,and Zinc inUnused Lubricating Oils by Atomic AbsorptionSpectrometry1This standard is issued under the fixed designation D4628;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.Scope*1.1 This test method is applicable for the determination ofmass percent barium from 0.005 to 1.0%,calcium andmagnesium from 0.002 to 0.3%,and zinc from 0.002 to 0.2%in lubricating oils.1.2 Higher concentrations can be determined by appropriatedilution.Lower concentrations of metals such as barium,calcium,magnesium,and zinc at about 10 ppm level can alsobe determined by this test method.Use of this test method forthe determination at these lower concentrations should be byagreement between the buyer and the seller.1.3 Lubricating oils that contain viscosity index improversmay give low results when calibrations are performed usingstandards that do not contain viscosity index improvers.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 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.Specific warningstatements are given in 3.1,6.3,and 8.1.2.Referenced Documents2.1 ASTM Standards:2D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3.Summary of Test Method3.1 A sample is weighed and base oil is added to 0.25 60.01-g total mass.Fifty millilitres of a kerosine solution,containing potassium as an ionization suppressant,are added,and the sample and oil are dissolved.(WarningHazardous.Potentially toxic and explosive.)Standards are similarlyprepared,always adding oil if necessary to yield a total mass of0.25 g.These solutions are burned in the flame of an atomicabsorption spectrophotometer.An acetylene/nitrous oxideflame is used.(WarningCombustible.Vapor harmful.)4.Significance and Use4.1 Some oils are formulated with metal-containing addi-tives that act as detergents,antioxidants,antiwear agents,etc.Some of these additives contain one or more of these metals:barium,calcium,zinc,and magnesium.This test methodprovides a means of determining the concentration of thesemetals that gives an indication of the additive content in theseoils.4.2 Several additive metals and their compounds are addedto the lubricating oils to give beneficial performance.(SeeTable 1.)5.Apparatus5.1 Atomic Absorption Spectrophotometer.5.2 Analytical Balance.5.3 Automatic Measuring Pipet or Volumetric Class A Pipet,50-mL capacity.5.4 Bottles with Screw Caps,60 mL.NOTE1Suitable volumetric flasks or plastic bottles may be substi-tuted.5.5 Shaker,Mechanical Stirrer,or Ultrasonic Bath,capableof handling 60-mL bottles.6.Reagents6.1 Base Oil,metal-free,with a viscosity of about 4 cSt at100C.A100 neutral oil which provides good solvency for1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved Dec.1,2014.Published January 2015.Originallyapproved in 1986.Last previous edition approved in 2011 as D4628 05(2011)1.DOI:10.1520/D4628-14.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 standards and additive concentrate is satisfactory.Highlyparaffinic oils should be avoided.6.2 2-Ethyl Hexanoic Acid,which has been determined to befree of interfering metals.6.3 Kerosine,Metal-FreeSee Notes 2-4.(WarningCombustible.Vapor harmful.)Distillation range from 170C to280C at 100 kPa(1 atm).When the kerosine solvent iscontaminated,it may be purified metal-free by running throughattapulgus clay.NOTE2Solvents other than kerosine,such as xylene MEK and soforth,may be used in this test method,however,the precision data quotedin Section 16 was obtained using kerosine.NOTE3Metal-free kerosine can be obtained from most laboratorysupply houses,but should be tested for metal content before using.NOTE4Satisfactory results have been obtained in this test method byusing Baker“kerosine”(deodorized)which h