ASTM D5788-1995(2005) Standard Guide for Spiking Organics into Aqueous Samples《有机物在水中样本的峰值标准导则》.pdf

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1、Designation: D 5788 95 (Reapproved 2005)Standard Guide forSpiking Organics into Aqueous Samples1This standard is issued under the fixed designation D 5788; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.

2、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 guide covers the general technique of “spiking”aqueous samples with organic analytes or components. It isintended to be applica

3、ble to a broad range of organic materialsin aqueous media. Although the specific details and handlingprocedures required for all types of compounds are notdescribed, this general approach is given to serve as a guidelineto the analyst in accurately preparing spiked samples forsubsequent analysis or

4、comparison. Guidance is also providedto aid the analyst in calculating recoveries and interpretingresults. It is the responsibility of the analyst to determinewhether the methods and materials cited here are compatiblewith the analytes of interest.1.2 The procedures in this guide are focused on “mat

5、rixspike” preparation, analysis, results, and interpretation. Theapplicability of these procedures to the preparation of calibra-tion standards, calibration check standards, laboratory controlstandards, reference materials, and other quality control mate-rials by spiking is incidental. A sample (the

6、 matrix) is fortified(spiked) with the analyte of interest for a variety of analyticaland quality control purposes. While the spiking of multiplesample test portions is discussed, the method of standardadditions is not covered.1.3 This guide is intended for use in conjunction with theindividual anal

7、ytical test method that provides procedures foranalysis of the analyte or component of interest. The testmethod is used to determine an analyte or componentsbackground level and, again after spiking, its now elevatedlevel. Each test method typically provides procedures not onlyfor samples, but also

8、for calibration standards or analyticalcontrol solutions, or both. These procedures include prepara-tion, handling, storage, preservation, and analysis techniques.These procedures are applicable by extension, using theanalysts judgement on a case-by-case basis, to spiking solu-tions, and are not rei

9、terated in this guide. See also PracticeE 200 for preparation and storage information.1.4 These procedures apply only to analytes that are solublein water at the concentration of the spike plus any backgroundmaterial, or to analytes soluble in a solvent that is itselfwater-soluble. The system used i

10、n the later case must result ina homogeneous solution of analyte and sample. Meaningfulrecovery data cannot be obtained if an aqueous solution orhomogeneous suspension of the analyte of interest in thesample cannot be attained.1.5 Matrix spiking may be performed in the field or in thelaboratory, dep

11、ending on which part of the analytical process isto be tested. Field spiking tests the recovery of the overallprocess, including preservation and shipping of the sample.Laboratory spiking tests the laboratory process only. Spiking ofsample extracts, concentrates, or dilutions will test only thatport

12、ion of the process subsequent to the addition of the spike.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther

13、esponsibility 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:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 3694 Practic

14、es for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD 3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of WaterD 4375 Practice for Basic Statistics in Committee D19 onWaterE 200 Practice for Preparation, Standardization, and St

15、or-age of Standard and Reagent Solutions for ChemicalAnalysis3. Terminology3.1 DefinitionsFor definitions of terms used in this guide,refer to Terminology D 1129.1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.06 on Methods for

16、 Analysis forOrganic Substances in Water.Current edition approved Dec. 1, 2005. Published January 2006. Originallyapproved in 1995. Last previous edition approved in 2001 as D 5788 95 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv

17、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2.

18、1 matrix spike, nthe quantity (mass) of a component(analyte) of interest which is added to a sample (matrix) inorder to test bias as measured by recovery (of that componentunder specific analytical conditions) and reported as percentrecovery (P).3.2.2 spike, vthe addition of a known amount of ananal

19、yte of known identity to a measured volume of a sample(from a specific matrix) to determine the efficiency with whichthe added analyte can be 88recovered” from (measured in) thatmatrix by the analytical system after exposure to a specificportion of an analytical process. Matrix spiking is a process

20、foraccomplishing this. The precision and bias estimates fromseveral trials under specific analytical conditions represent themeasurement efficiency with which the analyte may be deter-mined under these conditions.3.2.3 spiking solutionthe solution in which one or morespikes are dissolved (along with

21、 any necessary preservatives).This solution acts as a carrier to provide ease of measurementand more rapid and thorough mixing of the spike into thesample, as compared to adding the spike as a pure compound.4. Summary of Guide4.1 This guide describes a technique for the addition of aknown amount of

22、an organic analyte to an aqueous sample.Instructions are given to help prevent loss of volatile analytesin the sample headspace and to provide a homogeneoussolution for subsequent analysis.Appropriate concentrations ofthe spike relative to the original concentration in the sample arediscussed. Appli

23、cations of the technique and aids in theinterpretation of results obtained are described.5. Significance and Use5.1 Matrix spiking of samples is commonly used to deter-mine the bias under specific analytical conditions, or theapplicability of a test method to a particular sample matrix, bydeterminin

24、g the extent to which the added spike is recoveredfrom the sample matrix under these conditions. Reactions orinteractions of the analyte or component of interest with thesample matrix may cause a significant positive or negativeeffect on recovery and may render the chosen analytical, ormonitoring, p

25、rocess ineffectual for that sample matrix.5.2 Matrix spiking of samples can also be used to monitorthe performance of a laboratory, individual instrument, oranalyst as part of a regular quality assurance program. Changesin spike recoveries from the same or similar matrices over timemay indicate vari

26、ations in the quality of analyses and analyticalresults.5.3 Spiking of samples may be performed in the field or inthe laboratory, depending on what part of the analytical processis to be tested. Field spiking tests the recovery of the overallprocess, including preservation and shipping of the sample

27、 andmay be considered a measure of the stability of the analytes inthe matrix. Laboratory spiking tests the laboratory processonly. Spiking of sample extracts, concentrates, or dilutions willbe reflective of only that portion of the process subsequent tothe addition of the spike.5.4 Special precauti

28、ons shall be observed when nonlabora-tory personnel perform spiking in the field. It is recommendedthat all spike preparation work be performed in a laboratory byexperienced analysts so that the field operation consists solelyof adding a prepared spiking solution to the sample matrix.Training of fie

29、ld personnel and validation of their spikingtechniques are necessary to ensure that spikes are addedaccurately and reproducibly. Consistent and acceptable recov-eries from duplicate field spikes can be used to document thereproducibility of sampling and the spiking technique. Whenenvironmentally lab

30、ile compounds are used as spikes, thespiking solution shall be protected up to the time of use byappropriate means such as chilling, protection from sunlightand oxygen, or chemical preservation.NOTE 1Any field spiked sample, if known to the laboratory, should belabeled as a field spike in the final

31、results report.Also, whenever possible,field spiking of volatile compounds should be avoided.5.5 It is often tacitly assumed that the analyte component isrecovered from the sample to approximately the same extentthat a spike of the same analyte is recovered from a spikedsample. One reason that this

32、assumption may be incorrect isthat the spike may not be bound up in the sample (for example,with suspended matter) in the same way that the naturallyoccurring analyte is bound in the sample. The spike maytherefore be recovered from the sample differently than thebackground level of the analyte. For

33、this reason, as well as thefact that bias corrections can add variability, it is not goodpractice to correct analytical data using spike recoveries. Spikerecovery information should, however, be reported along withthe related sample analysis results.5.6 This guide is also applicable to the preparati

34、on and useof spikes for quantification by the method of standard additionsand to the addition of surrogates and internal standards.6. Apparatus6.1 Stirring ApparatusBorosilicate glass beads, 4 to 6 mmin diameter, or small TFE-coated magnetic stirring bars. Asmall non-heating variable-speed magnetic

35、stirrer is recom-mended for use with the stirring bar.6.2 MicrosyringesStandard gas chromatographic mi-crosyringes of borosilicate glass with stainless steel needles,suitable for injection of spiking solutions through aTFE-coatedsilicone septum. The TFE-tipped plungers may be contami-nated by certai

36、n analytes. If this is determined to be likely, asyringe may be dedicated to a single process, or a plain-tippedstainless steel plunger may be used to avoid cross-contamination. Sizes from 10 to 500 L are appropriate,depending on the concentration and sample volumes used.6.3 MicropipettorsStainless

37、steel micropipettors with dis-posable glass tips are preferable to syringes for introduction ofspiking solutions into open sample containers, since theydeliver more reproducibly and are less prone to cross-contamination. Sizes from 5 to 200 L are appropriate.6.4 SyringesBorosilicate glass syringes w

38、ith demountablestainless steel needles may be used to measure volumes ofsamples (spiked or unspiked) to be injected into purge-and-trapsample introduction systems.6.5 Volumetric Transfer PipetsClass A, used to deliverknown volumes of sample and to add larger volumes of spikingsolutions.D 5788 95 (20

39、05)26.6 Volumetric FlasksClass A volumetric flasks may beused to measure known volumes of sample.6.7 BalanceAn analytical (0.1-mg), semimicro (0.01-mg), or micro (0.001-mg) balance.7. Reagents7.1 Purity of ReagentsAt a minimum, reagent gradechemicals shall be used in all spike preparations. Spectrog

40、rade,high-pressure liquid chromatography (HPLC) grade, pesticidegrade, or ultrapure grade solvents shall be used to preparespiking solutions. Reagents of the highest available purity shallbe used for spike analytes and demonstrated to be free ofinterfering substances for the subsequent test methods

41、to beperformed. If possible, a primary standard grade shall be used.Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society.3Other gradesmay be used, provided (1) that reagent purity is unspecif

42、ied and(2) that it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without adversely affecting thebias and precision of subsequent determinations. Purchasedspiking solutions shall be demonstrated to be free of substancesthat would interfere with subsequent analy

43、ses being performed,and the suppliers stated concentration shall be verified byanalysis prior to use. Compensatory errors associated withself-referencing should be prevented by using spiking solutionsof a standard originating from a source, when available,different from that of the routine method ca

44、libration standards.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby the individual test method to be used to analyze a sampleafter spiking. If more than one test method is to be utilized, theminimum criteria of each test method

45、 must be met. If testmethod reagent water specifications are not available, refer-ences to water shall be understood to mean reagent waterconforming to Type I of Specification D 1193 and demon-strated to be free of interfering substances for the test(s) beingperformed.7.3 MethanolSpectrograde, HPLC

46、grade, or ultrapuregrade methanol is preferable for use as a solvent for water-insoluble analytes in most trace-level analyses. Other water-soluble solvents may be useful for certain analytes. Solventsshall be checked before use for interfering substances byanalysis.7.4 Spiking SolutionsSpiking solu

47、tions of each analyte ofinterest are prepared individually or in combination, eithergravimetrically or volumetrically, correcting for density (forliquid or solution standards). The preservation and storagecriteria found in the applicable analytical test method for itscalibration or check standards a

48、pply likewise to spiking solu-tions. The stability of a stored spiking solution shall be verifiedroutinely by the appropriate dilution of a portion of spikingsolution to the laboratorys analyte concentration of interest.Stability is demonstrated whenever the analyzed concentrationof a diluted spikin

49、g solution falls within the control limits fora routine laboratory control sample of the same concentration.Where solubilities permit, stock spiking solutions are custom-arily prepared 25 to 1000 times as concentrated as the workingspiking solution, and are diluted volumetrically to produce theworking spiking solution at the time of use. In some cases,concentrated solutions may be stable at 4C for substantiallylonger periods than dilute solutions. Alternatively, preparespike or spiking solution fresh for each batch of samples.8. Sampling8.1 Although sampling me