ASTM_E_1832_-_08_2012.pdf

Designation:E183208(Reapproved 2012)Standard Practice forDescribing and Specifying a Direct Current Plasma AtomicEmission Spectrometer1This standard is issued under the fixed designation E1832;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.1.Scope1.1 This practice describes the components of a directcurrent plasma(DCP)atomic emission spectrometer.Thispractice does not attempt to specify component tolerances orperformance criteria.This practice does,however,attempt toidentify critical factors affecting bias,precision,and sensitivity.A prospective user should consult with the vendor beforeplacing an order to design a testing protocol for demonstratingthat the instrument meets all anticipated needs.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 and determine the applica-bility of regulatory limitations prior to use.Specific hazardsstatements are give in Section 9.2.Referenced Documents2.1 ASTM Standards:2E135 Terminology Relating to Analytical Chemistry forMetals,Ores,and Related MaterialsE158 Practice for Fundamental Calculations to ConvertIntensities into Concentrations in Optical Emission Spec-trochemical Analysis(Withdrawn 2004)3E172 Practice for Describing and Specifying the ExcitationSource in Emission SpectrochemicalAnalysis(Withdrawn2001)3E406 Practice for Using Controlled Atmospheres in Spec-trochemical AnalysisE416 Practice for Planning and Safe Operation of a Spec-trochemical Laboratory(Withdrawn 2005)3E520 Practice for Describing Photomultiplier Detectors inEmission and Absorption SpectrometryE528 Practice for Grounding Basic Optical Emission Spec-trochemical Equipment(Withdrawn 1998)3E1097 Guide for Determination of Various Elements byDirect Current Plasma Atomic Emission Spectrometry3.Terminology3.1 For terminology relating to emission spectrometry,referto Terminology E135.4.Significance and Use4.1 This practice describes the essential components of theDCP spectrometer.This description allows the user or potentialuser to gain a basic understanding of this system.It alsoprovides a means of comparing and evaluating this system withsimilar systems,as well as understanding the capabilities andlimitations of each instrument.5.Overview5.1 A DCP spectrometer is an instrument for determiningconcentration of elements in solution.It typically is comprisedof several assemblies including a direct current(dc)electricalsource,a sample introduction system,components to form andcontain the plasma,an entrance slit,elements to disperseradiation emitted from the plasma,one or more exit slits,oneor more photomultipliers for converting the emitted radiationinto electrical current,one or more electrical capacitors forstoring this current as electrical charge,electrical circuitry formeasuring the voltage on each storage device,and a dedicatedcomputer with printer.The liquid sample is introduced into aspray chamber at a right angle to a stream of argon gas.Thesample is broken up into a fine aerosol by this argon stream andcarried into the plasma produced by a dc-arc discharge betweena tungsten electrode and two or more graphite electrodes.When the sample passes through the plasma,it is vaporizedand atomized,and many elements are ionized.Free atoms andions are excited from their ground states.When electrons ofexcited atoms and ions fall to a lower-energy state,photons ofspecific wavelengths unique to each emitting species areemitted.This radiation,focussed by a lens onto the entrance slitof the spectrometer and directed to an echelle grating and1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals,Ores,and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition approved Dec.1,2012.Published December 2012.Originallyapproved in 1996.Last previous edition approved in 2003 as E1832 03,which waswithdrawn October 2004 and reinstated in May 2008.DOI:10.1520/E1832-08R12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 quartz prism,is dispersed into higher orders of diffraction.Control on the diffraction order is accomplished by thelow-dispersion echelle grating.Radiation of specific wave-length or wavelengths passes through exit slits and impinges ona photo