1、Designation: D 6785 02Standard 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 (e) 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 d
4、issolution 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 c
5、ompounds 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 dete
7、rmination 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 Anio
8、ns 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 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is t
9、heresponsibility 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:3D 4840 Guide for Sample Chain-of-Custody ProceduresE 882 Guide for Accountability and
10、 Quality Control in theChemical Analysis LaboratoryE 1370 Guide for Air Sampling Strategies for Worker andWorkplace Protection2.2 Other Standards:4ISO 648:1977, Laboratory GlasswareOne-Mark PipettesISO 1042:1983, Laboratory GlasswareOne-Mark Volu-metric FlasksISO 3585:1991, Glass Plant, Pipelines an
11、d FittingsProperties of Borosilicate Glass 3.3ISO 3696:1987, Water for Laboratory UseSpecificationsand Test MethodsISO 6879:1983, Air QualityPerformance Characteristicsand Related Concepts For Air Quality MethodsISO 6955:1982, Analytical Spectroscopic MethodsFlameEmission, Atomic Absorption, and Ato
12、micFluorescenceVocabularyISO 7708:1995, Particle Size Definitions for Health RelatedSamplingISO 15202-2: 2001, WorkplaceAirDetermination of Met-als and Metalloids in Airborne Particulate Matter byInductively Coupled Plasma Atomic EmissionSpectrometryPart 2: Sample PreparationEN 689:1995, Workplace A
13、tmospheresGuidance for theAssessment of Exposure to ChemicalAgents for Compari-son with Limit Values and Measurement StrategyEN 1232:1997, Workplace AtmospheresPumps for Per-sonal Sampling of Chemical AgentsRequirements andTest MethodsEN 1540:1998, Workplace AtmospheresTerminology1This test method i
14、s under the jurisdiction of ASTM Committee D22 onSampling and Analysis of Atmospheres and is the direct responsibility of Subcom-mittee D22.04 on Workplace Atmospheres.Current edition approved April 10, 2002. Published June 2002.2The boldface numbers in parentheses refer to the list of references at
15、 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 ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American National St
16、andards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.EN 12919: 1999, Workplace AtmospheresPumps forSampling of ChemicalAgents with a Volume Flow Rate ofOver 5 L/MinRequiremen
17、ts and Test MethodsEN 13205: 2001, Workplace AtmospheresAssessment ofPerformance of Instruments for Measurement of AirborneParticle ConcentrationsEN ISO 8655-1, Piston-Operated Volumetric InstrumentsPart 1: Terminology, General Requirements and UserRecommendationsEN ISO 8655-2 Piston-Operated Volume
18、tric InstrumentsPart 2: Piston Pipettes5EN ISO 8655-5 Piston-Operated Volumetric InstrumentsPart 5: Dispensers5EN ISO 8655-6 Piston-Operated Volumetric InstrumentsPart 6: Gravimetric Test Methods53. Terminology3.1 General Definitions:3.1.1 breathing zonethe space around the workers facefrom where he
19、 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 a line joining theears; the base of the hemisphere is a plane through this line, theto
20、p 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 natural state or asproduced, used or released including release as waste, by anywork acti
21、vity, 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 limit valuereference figure for concentration of achemical agent in air.3.1.4.1 Discussio
22、nAn 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 air and includingstorage and transportation of the sample.3.1.6 operating timethe perio
23、d 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 of a specific chemical agent.3.1.7.1 DiscussionExamples of limit values for different
24、reference 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, averagedover the reference period.3.1.8.1 DiscussionA more detailed discussion of TWAconcen
25、trations 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 workplacethe defined area or areas in which thework activities are carried out. EN 154
26、03.2 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 total airborneparticles which is inhaled through the nose and mouth.3.2.2.1 DiscussionThe
27、 inhalable fraction depends on thespeed and direction of air movement, on breathing rate andother factors. ISO 77083.2.3 respirable conventiona target specification for sam-pling instruments when the respirable fraction is of interest.ISO 77083.2.4 respirable fractionthe mass fraction of inhaled par
28、-ticles penetrating to the unciliated airways. ISO 77083.2.5 total airborne particlesall particles surrounded byair in a given volume of air.3.2.5.1 DiscussionBecause all measuring instruments aresize-selective to some extent, it is often impossible to measurethe total airborne particles concentrati
29、on. ISO 77083.3 Sampling Definitions:3.3.1 personal samplera device attached to a person thatsamples air in the 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 devi
30、ce for collecting airborne particles.3.3.3.1 DiscussionInstruments used to collect airborneparticles are frequently 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 st
31、atic (area) sampling.3.3.5 static sampling; area samplingthe process of airsampling carried out in a particular 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 diss
32、olution of the sample.3.4.2 sample preparationall operations carried out on asample, after transportation and storage, 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 dissolutio
33、n, but possibly needing to be subjected tofurther operations in order to produce a test solution that isready for 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 w
34、hichit is ready for analysis.3.5 Statistical Terms:3.5.1 analytical recoveryratio of the mass of analytemeasured when a sample is analyzed to the known mass ofanalyte in that sample, expressed as a percentage.5To be published.D67850223.5.2 biasconsistent deviation of the results of a measure-ment pr
35、ocess from the true value of the air quality character-istic itself. ISO 68793.5.3 overall uncertainty(of a measuring procedure 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
36、combination ofbias and precision, usually in accordance with the formula:|x2 xref# | 1 2sxref3 100where:x= mean value of results 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
37、 closeness of agreement of results ob-tained by applying the method several times under prescribedconditions. ISO 68793.5.4.1 DiscussionPrecision is often expressed in terms ofthe relative standard deviation.3.5.5 true valuethe value which characterizes a quantityperfectly defined in the conditions
38、which exist when thatquantity is considered. ISO 3534-13.5.5.1 DiscussionThe true value of a quantity is a theo-retical concept 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.
39、For personalsampling, a sampler designed to collect the inhalable fractionof airborne particles may be used.NOTE 1The inhalable 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 Occup
40、ational Safetyand Health Administration (OSHA) (29 CFR 1910.1025) are based on theuse of samplers that were not specifically designed to meet the inhalableconvention.4.2 The filter and collected sample are subjected to adissolution procedure in order to extract lead. The sampledissolution procedure
41、may use one of three techniques: hotplate digestion, microwave digestion or ultrasonic extraction.4.3 Sample solutions are analyzed for lead content byaspirating into the oxidizing air-acetylene flame of an atomicabsorption spectrometer equipped with a lead hollow cathodelamp or electrodeless discha
42、rge lamp. Absorbance measure-ments are made at 283.3 nm, and analytical results are obtainedby the analytical curve technique (see 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 abso
43、rption spectrometry. Ali-quots of the test solution are injected into a graphite furnace,and after drying and sample ashing stages, the sample isatomized electrothermally. Absorbance measurements aremade at 283.3 nm with background correction, and results areobtained by the analytical curve techniqu
44、e (see 6.1 of ISO6955).4.5 The results may be used for the assessment of workplaceexposures to airborne particulate lead (see EN 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 l
45、ead ions (Pb2+)by the sample dissolution procedures described in 11.2. How-ever, certain lead compounds, for example lead silicate, 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 effec
46、tiveness of these proceduresfor the dissolution of particulate lead compounds that may bepresent in the test atmosphere, then this 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 re
47、fining, battery manufacture, construction, etc.,is at risk through exposure by inhalation of particulate lead andlead compounds. Industrial hygienists and other public healthprofessionals need to determine the effectiveness of measurestaken to control workers exposure, and this is generallyachieved
48、by making workplace air measurements. This stan-dard has been published in order to make available a methodfor making valid exposure measurements for lead. It will be ofbenefit to: agencies concerned with health and safety at work;industrial hygienists and other public health professionals;analytica
49、l laboratories; industrial users of metals and metal-loids and their workers, etc. It has been assumed in the draftingof this standard 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
