ASTM_D_4185_-_06_2011.pdf

Designation:D418506(Reapproved 2011)Standard Practice forMeasurement of Metals in Workplace Atmospheres byFlame Atomic Absorption Spectrophotometry1This standard is issued under the fixed designation D4185;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 covers the collection,dissolution,anddetermination of trace metals in workplace atmospheres,byflame atomic absorption spectrophotometry.1.2 The sensitivity,detection limit,and optimum workingconcentration for 23 metals are given in Table 1.1.3 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.(Specific safetyprecautionary statements are given in Section 9.)2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1356 Terminology Relating to Sampling and Analysis ofAtmospheresD1357 Practice for Planning the Sampling of the AmbientAtmosphereD3195 Practice for Rotameter CalibrationD5337 Practice for Flow Rate Adjustment of Personal Sam-pling PumpsD7035 Test Method for Determination of Metals and Met-alloids in Airborne Particulate Matter by InductivelyCoupled Plasma Atomic Emission Spectrometry(ICP-AES)3.Terminology3.1 DefinitionsFor definitions of terms used in thispractice,refer to Terminology D1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 blank signalthat signal which results from all addedreagents and a clean membrane filter prepared and analyzedexactly in the same way as the samples.3.2.2 instrumental detection limitthat concentration of agiven element which produces a signal three times the standarddeviation of the reagent blank signal.3.2.3 working range for an analytical precision better than3%the range of sample concentrations that will absorb 10 to70%of the incident radiation(0.05 to 0.52 absorbance units).NOTE1Values for instrumental detection limit may vary frominstrument to instrument.4.Summary of Practice4.1 Workplace air samples are collected on membrane filtersand treated with nitric acid to destroy the organic matrix and todissolve the metals present.The analysis is subsequently madeby flame atomic absorption spectrophotometry(AAS).4.2 Samples and standards are aspirated into an appropriateAAS flame.A hollow cathode or electrodeless discharge lampfor the metal being determined provides a source of character-istic radiation energy for that particular metal.The absorptionof this characteristic energy by the atoms of interest in theflame is related to the concentration of the metal in theaspirated sample.The flame and operating conditions for eachelement are listed in Table 2.5.Significance and Use5.1 The health of workers in many industries is at riskthrough exposure by inhalation to toxic metals.Industrialhygienists and other public health professionals need to deter-mine the effectiveness of measures taken to control workersexposures,and this is generally achieved by making workplaceair measurements.Exposure to some metal-containing particleshas been demonstrated to cause dermatitis,skin ulcers,eyeproblems,chemical pneumonitis,and other physical disorders(1).35.2 AAS is capable of quantitatively determining mostmetals in air samples at the levels required by federal,state,1This practice is under the jurisdiction ofASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.Current edition approved Oct.1,2011.Published October 2011.Originallyapproved in 1990.Last previous edition approved in 2006 as D4185-06.DOI:10.1520/D4185-06R11.2For 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.3Boldface numbers in parentheses refer to the list of references appended tothese methods.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 and local occupational health and air pollution regulations.Theanalysis results can be used for the assessment of workplaceexposures to metals in workplace air.6.Interferences6.1 In AAS the occurrence of interferences is less commonthan in many other analytical techniques.Interferences canoccur,however,and when encountered are corrected for asindicated in the following sections.The known interferencesand correction methods for each metal are indicated in Table 2.The methods of standard additions and background monitoringand correction(2-5)are used to identify the presence of aninterference.Insofar as possible,the