1、Designation: D 6785 08Standard Test Method forDetermination of Lead in Workplace Air Using Flame orGraphite Furnace Atomic Absorption Spectrometry1This standard is issued under the fixed designation D 6785; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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 standard specifies flame and graphite furnaceatomic absorption spectrometric
3、methods for the determinationof the time-weighted average mass concentration of particulatelead and lead compounds in workplace air.1.2 The method is applicable to personal sampling of theinhalable fraction of airborne particles, as defined in ISO 7708,and to static (area) sampling.1.3 The sample di
4、ssolution procedure specifies hot plate ormicrowave digestion, or ultrasonic extraction (11.2). Thesample dissolution procedure is not effective for all leadcompounds (see Section 5). The use of an alternative, morevigorous dissolution procedure is necessary when it is desiredto extract lead from co
5、mpounds present in the test atmospherethat are insoluble using the dissolution procedures describedherein. For example if it is desired to determine silicate lead, ahydrofluoric acid dissolution procedure is required.1.4 The flame atomic absorption method is applicable to thedetermination of masses
6、of approximately 1 to 200 g of leadper sample, without dilution (1).2The graphite furnace atomicabsorption method is applicable to the determination of massesof approximately 0.01 to 0.5 g of lead per sample, withoutdilution (1).1.5 The ultrasonic extraction procedure has been validatedfor the deter
7、mination of masses of approximately 20 to 100 gof lead per sample, for laboratory-generated lead fume air filtersamples (2).1.6 The concentration range for lead in air for which thisprocedure is applicable is determined in part by the samplingprocedure selected by the user (see Section 10).1.7 Anion
8、s that form precipitates with lead may interfere,but this potential interference is overcome by the addition ofthe disodium salt of ethylenediamine tetraacetic acid (EDTA)when necessary.1.8 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thi
9、sstandard.1.9 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. Re
10、ferenced Documents2.1 ASTM Standards:3D 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 3195 Practice for Rotameter CalibrationD 4840 Guide for Sample Chain-of-Custody ProceduresE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1370 Guide for Ai
11、r Sampling Strategies for Worker andWorkplace ProtectionE 1792 Specification for Wipe Sampling Materials for Leadin Surface Dust2.2 Other Standards:4ISO 648 Laboratory GlasswareOne-Mark PipettesISO 1042 Laboratory GlasswareOne-Mark VolumetricFlasksISO 3585 Glass Plant, Pipelines and FittingsProperti
12、es ofBorosilicate Glass 3.3ISO 3696 Water for Laboratory UseSpecifications andTest MethodsISO 6879 Air QualityPerformance Characteristics andRelated Concepts For Air Quality MethodsISO 6955 Analytical Spectroscopic MethodsFlame Emis-sion, Atomic Absorption, and Atomic FluorescenceVocabularyISO 7708
13、Particle Size Definitions for Health Related Sam-pling1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.04 on Workplace AirQuality.Current edition approved Dec. 15, 2008. Published January 2009. Originallyapproved in
14、2002. Last previous edition approved in 2002 as D 6785 - 02.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
15、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consho
16、hocken, PA 19428-2959, United States.ISO 15202-2 Workplace AirDetermination of Metals andMetalloids in Airborne Particulate Matter by InductivelyCoupled Plasma Atomic Emission SpectrometryPart 2:Sample PreparationEN 689 WorkplaceAtmospheresGuidance for theAssess-ment of Exposure to Chemical Agents f
17、or Comparisonwith Limit Values and Measurement StrategyEN 1232 Workplace AtmospheresPumps for PersonalSampling of Chemical AgentsRequirements and TestMethodsEN 1540 Workplace AtmospheresTerminologyEN 12919 Workplace AtmospheresPumps for Samplingof Chemical Agents with a Volume Flow Rate of Over 5L/M
18、inRequirements and Test MethodsEN 13205 Workplace AtmospheresAssessment of Perfor-mance of Instruments for Measurement of Airborne Par-ticle ConcentrationsEN ISO 8655-1, Piston-Operated Volumetric InstrumentsPart 1: Terminology, General Requirements and UserRecommendationsEN ISO 8655-2 Piston-Operat
19、ed Volumetric InstrumentsPart 2: Piston PipettesEN ISO 8655-5 Piston-Operated Volumetric InstrumentsPart 5: DispensersEN ISO 8655-6 Piston-Operated Volumetric InstrumentsPart 6: Gravimetric Test Methods3. Terminology3.1 General Definitions: For definitions of other terms inthis Test Method, refer to
20、 Terminology D 1356.3.1.1 breathing zonethe space around the workers facefrom where he or she takes his or her breath. For technicalpurposes a more precise definition is as follows: hemisphere(generally accepted to be 0.3 m in radius) extending in front ofthe human face, centered on the midpoint of
21、a line joining theears; the base of the hemisphere is a plane through this line, thetop of the head and the larynx. The definition is not applicablewhen respiratory protective equipment is used. EN 15403.1.2 chemical agentany chemical element or compound,on its own or admixed as it occurs in the nat
22、ural state or asproduced, used or released including release as waste, by anywork activity, whether or not produced intentionally andwhether or not placed on the market. EN 15403.1.3 exposure (by inhalation)a situation in which achemical agent is present in air which is inhaled by a person.3.1.4 lim
23、it valuereference figure for concentration of achemical agent in air.3.1.4.1 DiscussionAn example is the Threshold LimitValue (TLV) for a given substance in workplace air, asestablished by the ACGIH (3).3.1.5 measuring procedureprocedure for sampling andanalyzing one or more chemical agents in the a
24、ir and includingstorage and transportation of the sample.3.1.6 operating timethe period during which a samplingpump can be operated at specified flow rate and back pressurewithout recharging or replacing the battery. EN 12323.1.7 reference periodthe specified period of time statedfor the limit value
25、 of a specific chemical agent.3.1.7.1 DiscussionExamples of limit values for differentreference periods are short-term and long-term exposure limits,such as those established by the ACGIH (3).3.1.8 time weighted average (TWA) concentrationtheconcentration of a chemical agent in the atmosphere, avera
26、gedover the reference period.3.1.8.1 DiscussionA more detailed discussion of TWAconcentrations and their use can be found in the AmericanConference of Government Industrial Hygienists publicationThreshold Limit Values for Chemical Substances and PhysicalAgents; Biological Exposure Indices (3).3.1.9
27、workplacethe defined area or areas in which thework activities are carried out. EN 15403.2 Particle Size Fraction Definitions:3.2.1 inhalable conventiona target specification for sam-pling instruments when the inhalable fraction is of interest.ISO 77083.2.2 inhalable fractionthe mass fraction of tot
28、al airborneparticles which is inhaled through the nose and mouth.3.2.2.1 DiscussionThe inhalable fraction depends on thespeed and direction of air movement, on breathing rate andother factors. ISO 77083.3 Sampling Definitions:3.3.1 personal samplera device attached to a person thatsamples air in the
29、 breathing zone. EN 15403.3.2 personal samplingThe process of sampling carriedout using a personal sampler. EN 15403.3.3 sampling instrument; samplerfor the purposes ofthis standard, a device for collecting airborne particles.3.3.3.1 DiscussionInstruments used to collect airborneparticles are freque
30、ntly referred to by a number of other terms,for example, sampling heads, filter holders, filter cassettes etc.3.3.4 static sampler; area samplera device, not attachedto a person, used in static (area) sampling.3.3.5 static sampling; area samplingthe process of airsampling carried out in a particular
31、 location.3.4 Analytical Definitions:3.4.1 sample dissolutionthe process of obtaining a solu-tion containing the analytes of interest from a sample. This mayor may not involve complete dissolution of the sample.3.4.2 sample preparationall operations carried out on asample, after transportation and s
32、torage, to prepare it foranalysis, including transformation of the sample into a mea-surable state, where necessary.3.4.3 sample solutionsolution prepared by the process ofsample dissolution, but possibly needing to be subjected tofurther operations in order to produce a test solution that isready f
33、or analysis.3.4.4 test solutionsolution prepared by the process ofsample dissolution and, if necessary, having been subjected toany further operations required to bring it into a state in whichit is ready for analysis.3.5 Statistical Terms:3.5.1 analytical recoveryratio of the mass of analytemeasure
34、d when a sample is analyzed to the known mass ofanalyte in that sample, expressed as a percentage.D67850823.5.2 biasconsistent deviation of the results of a measure-ment process from the true value of the air quality character-istic itself. ISO 68793.5.3 overall uncertainty(of a measuring procedure
35、or ofan instrument) quantity used to characterize as a whole theuncertainty of a result given by an apparatus or measuringprocedure. It is expressed, as a percentage, by a combination ofbias and precision, usually in accordance with the formula:|x2 xref# | 1 2sxref3 100where:x= mean value of results
36、 of a number (n) of repeatedmeasurements,xref= true or accepted reference value of concentration,ands = standard deviation of repeated measurements.EN 4823.5.4 precisionthe closeness of agreement of results ob-tained by applying the method several times under prescribedconditions. ISO 68793.5.4.1 Di
37、scussionPrecision is often expressed in terms ofthe relative standard deviation.3.5.5 true valuethe value which characterizes a quantityperfectly defined in the conditions which exist when thatquantity is considered. ISO 3534-13.5.5.1 DiscussionThe true value of a quantity is a theo-retical concept
38、and, in general, cannot be known exactly.EN 15404. Summary of Test Method4.1 A known volume of air is drawn through a filter tocollect particulate lead and lead compounds. For personalsampling, a sampler designed to collect the inhalable fractionof airborne particles may be used.NOTE 1The inhalable
39、convention may not be the regulated samplingconvention in all countries where this standard may be applicable. In theUSA, for example, limit values promulgated by the Occupational Safetyand Health Administration (OSHA) (29 CFR 1910.1025) are based on theuse of samplers that were not specifically des
40、igned to meet the inhalableconvention.4.2 The filter and collected sample are subjected to adissolution procedure in order to extract lead. The sampledissolution procedure may use one of three techniques: hotplate digestion, microwave digestion or ultrasonic extraction.4.3 Sample solutions are analy
41、zed for lead content byaspirating into the oxidizing air-acetylene flame of an atomicabsorption spectrometer equipped with a lead hollow cathodelamp or electrodeless discharge lamp. Absorbance measure-ments are made at 283.3 nm, and analytical results are obtainedby the analytical curve technique (s
42、ee 6.1 of ISO 6955).4.4 For accurate lead determination when the concentrationof lead in the solution is low, the analysis may be repeatedusing graphite furnace atomic absorption spectrometry. Ali-quots of the test solution are injected into a graphite furnace,and after drying and sample ashing stag
43、es, the sample isatomized electrothermally. Absorbance measurements aremade at 283.3 nm with background correction, and results areobtained by the analytical curve technique (see 6.1 ofISO 6955).4.5 The results may be used for the assessment of workplaceexposures to airborne particulate lead (see EN
44、 689).5. Reactions5.1 In general, the overwhelming majority of particulatelead compounds that are commonly found in samples ofworkplace air are converted to water-soluble lead ions (Pb2+)by the sample dissolution procedures described in 11.2. How-ever, certain lead compounds, for example lead silica
45、te, mightnot be dissolved. If necessary, a dissolution procedure employ-ing hydrofluoric acid should be used to dissolve silicate lead. Ifthere is any doubt about the effectiveness of these proceduresfor the dissolution of particulate lead compounds that may bepresent in the test atmosphere, then th
46、is shall be investigatedbefore proceeding with the method (see Section 11).6. Significance and Use6.1 The health of workers in many industries, for example,mining, metal refining, battery manufacture, construction, etc.,is at risk through exposure by inhalation of particulate lead andlead compounds.
47、 Industrial hygienists and other public healthprofessionals need to determine the effectiveness of measurestaken to control workers exposure, and this is generallyachieved by making workplace air measurements. This stan-dard has been published in order to make available a methodfor making valid expo
48、sure measurements for lead. It will be ofbenefit to: agencies concerned with health and safety at work;industrial hygienists and other public health professionals;analytical laboratories; industrial users of metals and metal-loids and their workers, etc. It has been assumed in the draftingof this st
49、andard that the execution of its provisions, and theinterpretation of the results obtained, is entrusted to appropri-ately qualified and experienced people.6.2 The measuring procedure shall comply with any rel-evant International, European or National Standard that speci-fies performance requirements for procedures for measuringchemical agents in workplace air (for example, EN 482).7. ReagentsNOTE 2During the analysis, use only reagents of recognized analyti-cal grade, and only water as specified in 7.1.7.1 Water, complying
