1、Designation: D5788 95 (Reapproved 2017)Standard Guide forSpiking Organics into Aqueous Samples1This standard is issued under the fixed designation D5788; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、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 guide covers the general technique of “spiking”aqueous samples with organic analytes or components. It isintended to be applicable
3、 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 com
4、parison. 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 “matrix
5、spike” 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 ma
6、trix) 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 analyti
7、cal 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 for
8、 calibration standards or analyticalcontrol solutions, or both. These procedures includepreparation, handling, storage, preservation, and analysis tech-niques.These procedures are applicable by extension, using theanalysts judgement on a case-by-case basis, to spikingsolutions, and are not reiterate
9、d in this guide. See also PracticeE200 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 in the l
10、ater 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, depending
11、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 thatportion of
12、the process subsequent to the addition of the spike.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
13、ility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization
14、 established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification fo
15、r Reagent WaterD3694 Practices for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of Water1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcomm
16、ittee D19.06 on Methods for Analysis forOrganic Substances in Water.Current edition approved Dec. 15, 2017. Published January 2018. Originallyapproved in 1995. Last previous edition approved in 2011 as D5788 95 (2011).DOI: 10.1520/D5788-95R17.2For referenced ASTM standards, visit the ASTM website, w
17、ww.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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis
18、international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT
19、) Committee.1D4375 Practice for Basic Statistics in Committee D19 onWaterE200 Practice for Preparation, Standardization, and Storageof Standard and Reagent Solutions for Chemical Analysis3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology D1129.3.2
20、 Definitions of Terms Specific to This Standard:3.2.1 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.
21、2.2 spike, vthe addition of a known amount of ananalyte of known identity to a measured volume of a sample(from a specific matrix) to determine the efficiency with whichthe added analyte can be “recovered” from (measured in) thatmatrix by the analytical system after exposure to a specificportion of
22、an analytical process. Matrix spiking is a process 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 i
23、n which one or morespikes are dissolved (along with 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 describe
24、s a technique for the addition of aknown amount of 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 origi
25、nal concentration in the sample arediscussed. Applications 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
26、 method to a particular sample matrix, bydetermining 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 an
27、d may render the chosen analytical, ormonitoring, process 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
28、same or similar matrices over timemay indicate variations 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
29、, including preservation and shipping of the sample 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 subseque
30、nt tothe addition of the spike.5.4 Special precautions 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 sp
31、iking solution to the sample matrix.Training of field 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
32、 and the spiking technique. Whenenvironmentally labile 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 laborato
33、ry, should belabeled as a field spike in the final 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 r
34、ecovered from a spikedsample. One reason that this 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 differ
35、ently than thebackground level of the analyte. For 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
36、.5.6 This guide is also applicable to the preparation 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 stirrin
37、g bars. Asmall non-heating variable-speed magnetic 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
38、 TFE-tipped plungers may be contami-nated by certain 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 a
39、nd sample volumes used.D5788 95 (2017)26.3 MicropipettorsStainless 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
40、 to 200 L are appropriate.6.4 SyringesBorosilicate glass syringes with 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
41、 sample and to add larger volumes of spikingsolutions.6.6 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
42、 shall be used in all spike preparations. Spectrograde,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 ofinter
43、fering substances for the subsequent test methods 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
44、used, provided (1) that reagent purity is unspecified 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 su
45、bstancesthat would interfere with subsequent analyses 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 avai
46、lable,different from that of the routine method calibration 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
47、 utilized, theminimum criteria of each test method 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 D1193 and demonstratedto be free of interfering substances for the test(s)
48、 beingperformed.7.3 MethanolSpectrograde, HPLC 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 substanc
49、es byanalysis.7.4 Spiking SolutionsSpiking solutions 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 apply 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.S
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