1、Designation: D4691 11D4691 17Standard Practice forMeasuring Elements in Water by Flame Atomic AbsorptionSpectrophotometry1This standard is issued under the fixed designation D4691; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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. Scope*1.1 This practice covers general considerations for the quantitative determination of elements in water and was
3、te water by flameatomic absorption spectrophotometry. Flame atomic absorption spectrophotometry is simple, rapid, and applicable to a largenumber of elements in drinking water, surface waters, and domestic and industrial wastes. While some waters may be analyzeddirectly, others will require pretreat
4、ment.1.2 Detection limits, sensitivity, and optimum ranges of the elements will vary with the various makes and models ofsatisfactory atomic absorption spectrometers. The actual concentration ranges measurable by direct aspiration are given in thespecific test method for each element of interest. In
5、 the majority of instances the concentration range may be extended lower byuse of electrothermal atomization and conversely extended upwards by using a less sensitive wavelength or rotating the burnerhead. Detection limits by direct aspiration may also be extended through sample concentration, solve
6、nt extraction techniques, orboth. Where direct aspiration atomic absorption techniques do not provide adequate sensitivity, the analyst is referred to PracticeD3919 or specialized procedures such as the gaseous hydride method for arsenic (Test Methods D2972) and selenium (TestMethods D3859), and the
7、 cold vapor technique for mercury (Test Method D3223).1.3 Because of the differences among various makes and models of satisfactory instruments, no detailed operating instructionscan be provided. Instead the analyst should follow the instructions provided by the manufacturer of a particular instrume
8、nt.1.4 The values stated in either SI or inch-pound units are to be regarded as the standard. The values given in parentheses arefor information only.mathematical conversion to inch-pound units that are provided for information only and are not consideredstandard.1.5 This standard does not purport t
9、o address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements see Section 9.1.6 Thi
10、s international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TB
11、T) Committee.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2972 Test Methods for Arsenic in WaterD3223 Test Method for Total Mercury in WaterD3370 Practices for Sampling Water from Closed ConduitsD3859 Test Methods for Selenium in
12、 WaterD3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption SpectrophotometryD4453 Practice for Handling of High Purity Water SamplesD5810 Guide for Spiking into Aqueous Samples1 This practice is under the jurisdiction of ASTM Committee D19 on Water and is the di
13、rect responsibility of Subcommittee D19.05 on Inorganic Constituents in Water.Current edition approved Sept. 1, 2011June 1, 2017. Published September 2011June 2017. Originally approved in 1987. Last previous edition approved in 20072011 asD4691 02D4691 11.(2007). DOI: 10.1520/D4691-11.10.1520/D4691-
14、17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only
15、 to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versio
16、nof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D5847 Practice for Writing Quality Contro
17、l Specifications for Standard Test Methods for Water AnalysisE178 Practice for Dealing With Outlying ObservationsE520 Practice for Describing Photomultiplier Detectors in Emission and Absorption SpectrometryE863 Practice for Describing Atomic Absorption Spectrometric Equipment (Withdrawn 2004)33 The
18、 last approved version of this historical standard is referenced on www.astm.org.D4691 1723. Terminology3.1 Definitions:3.1.1 For definition of terms used in this practice, refer to Terminology D1129.3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.3.2
19、 Definitions of Terms Specific to This Standard:3.2.1 absorbance, nthe logarithm to the base 10 of the reciprocal of the transmittance ( T). A = log10 (1/T) = log10 T.3.2.2 absorptivity, nthe absorbance (A) divided by the product of the sample path length (b) and the concentration (c).a = A/bc.3.2.3
20、 atomic absorption, nthe absorption of electromagnetic radiation by an atom resulting in the elevation of electrons fromtheir ground states to excited states.3.2.3.1 DiscussionAtomic-absorption spectrophotometry involves the measurement of light absorbed by atoms of interest as a function of theconc
21、entration of those atoms in a particular solution.3.2.4 continuing calibration blank, na solution containing no analytes (of interest) which is used to verify blank response andfreedom from carryover.3.2.5 continuing calibration verification, na solution (or set of solutions) of known concentration
22、used to verify freedom fromexcessive instrumental drift; the concentration is to cover the range of calibration curve.3.2.6 detection limit, nin atomic absorption, is a function of the sensitivity and the signaltonoise ratio in the analysis of aspecific element for a given set of parameters.3.2.6.1
23、DiscussionThe instrument detection limit is determined statistically as some multiple, usually two or three times the standard deviation of thesignal-to-noise ratio.3.2.7 laboratory control sample (LCS)(LCS), na solution with the certified concentration(s) of the analytes.3.2.8 monochromator, na dev
24、ice used for isolating a narrow portion of the spectrum by means of a grating or prism.3.2.9 nebulizer, nin atomic absorption, the burner-system portion where the sample solution is converted into fine mist.3.2.10 optimum concentration range, na limited concentration range, that may be extended down
25、ward with scale expansion(used to measure very small concentrations) or upward by using a less sensitive wavelength or by rotating the burner head.3.2.10.1 DiscussionThe range varies with the characteristic concentration of the instrument and the operating conditions employed.3.2.11 sensitivity, nth
26、e analyte concentration (sometimes referred to as the characteristic concentration) that produces anabsorbance of 0.0044 absorbance units (1 % absorption) when compared to the analytical blanks.4,5,63.2.11.1 DiscussionThe characteristic concentration varies with instrumental conditions and atomizati
27、on efficiency, as well as other factors and shouldbe determined as conditions change. The characteristic concentration is determined by the following equation:characteristic concentration5C 30.0044/A (1)where:C = concentration of the analyte, and4 Bennett, P. A., and Rothery, E., “Introducing Atomic
28、 Absorption Analysis,” Varian Publication, Mulgrave, Australia, 1983.Bennett, P. A., and Rothery, E., IntroducingAtomic Absorption Analysis, Varian Publication, Mulgrave, Australia, 1983.5 Price, W. J., “Spectrochemical Analysis by Atomic Absorption,” John Wiley flameSUMMARY OF CHANGESCommittee D19
29、has identified the location of selected changes to this standard since the last issue (D4691 02(2007)D4691 11) that may impact the use of this standard. (Approved June 1, 2017.)(1) The SI statement Revised 1.4 was added to Sectionto update the units 1.of measurement statement.(2) D1192 was removed f
30、rom Revised Section 23 to update and 10.2.add terms.(3) Updated TerminologyRevised 7.5 section.with information on data storage and reduction devices.(4) Revised 8.3 and 9.5 for updating pressure units to SI units.(5) Added 8.8 for information on filter paper.(6) Added Note 2 for information to allo
31、w for pH of the samples in the library.(7) Rewrote and expanded Section 14.D4691 1710ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of th
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