ASTM_D_3919_-_08.pdf

Designation:D391908Standard Practice forMeasuring Trace Elements in Water by Graphite FurnaceAtomic Absorption Spectrophotometry1This standard is issued under the fixed designation D3919;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 general considerations for thequantitative determination of trace elements in water andwastewater by graphite furnace atomic absorption spectropho-tometry.Furnace atomizers are a most useful means of extend-ing detection limits;however,the practice should only be usedat concentration levels below the optimum range of directflame aspiration atomic absorption spectrophotometry.Be-cause of differences between various makes and models ofsatisfactory instruments,no detailed operating instructions canbe provided for each instrument.Instead,the analyst shouldfollow the instructions provided by the manufacturer of aparticular instrument.1.2 Wavelengths,estimated detection limits,and optimumconcentration ranges are given in the individual methods.Ranges may be increased or decreased by varying the volumeof sample injected or the instrumental settings or by the use ofa secondary wavelength.Samples containing concentrationshigher than those given in the optimum range may be dilutedor analyzed by other techniques.1.3 This technique is generally not applicable to brines andseawater.Special techniques such as separation of the traceelements from the salt,careful temperature control throughramping techniques,or matrix modification may be useful forthese samples.1.4 The analyst is encouraged to consult the literature asprovided by the instrument manufacturer as well as varioustrade journals and scientific publications.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water Analysis3.Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice,refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 graphite furnacean electrothermal graphite devicecapable of reaching the specified temperatures required by theelement being determined.3.2.2 platform or similar device a flat,grooved or un-grooved piece of pyrolytic graphite inserted in the graphitetube on which the sample is placed(1).34.Summary of Practice4.1 The element is determined by an atomic absorptionspectrophotometer used in conjunction with a graphite furnace.The principle is essentially the same as with direct flameaspiration atomic absorption except a furnace,rather than aflame,is used to atomize the sample.The elemental atoms to bemeasured are placed in the beam of radiation by increasing the1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.05 on Inorganic Constituents inWater.Current edition approved Nov.15,2008.Published November 2008.Originallyapproved in 1980.Last previous edition approved in 2004 as D3919 04.DOI:10.1520/D3919-08.2For 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 boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 temperature of the furnace,thereby causing the injected speci-men to be volatilized.Radiation from a given excited elementis passed through the vapor containing ground-state atoms ofthat element.The decrease in intensity of the transmittedradiation is a measure of the amount of the ground-stateelement in the vapor.A monochromator isolates the character-istic radiation from the hollow-cathode lamp and a photosen-sitive device measures the attenuated transmitted radiation.4.2 Dissolved elements are determined on a filtered samplewith n