1、Designation: D5788 95 (Reapproved 2011)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 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 reiter
9、ated 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 th
10、e 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, dependi
11、ng 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
12、of 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 therespon
13、sibility 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 WaterD3694 Practices for P
14、reparation of Sample Containers andfor Preservation of Organic ConstituentsD3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of WaterD4375 Practice for Basic Statistics in Committee D19 onWater1This guide is under the jurisdiction of ASTM Committee D19 on Wa
15、ter and isthe direct responsibility of Subcommittee D19.06 on Methods for Analysis forOrganic Substances in Water.Current edition approved May 1, 2011. Published June 2011. Originallyapproved in 1995. Last previous edition approved in 2005 as D5788 95 (2005).DOI: 10.1520/D5788-95R11.2For referenced
16、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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
17、ohocken, PA 19428-2959, United States.E200 Practice for Preparation, Standardization, and Storageof Standard and Reagent Solutions for Chemical Analysis3. Terminology3.1 DefinitionsFor definitions of terms used in this guide,refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standa
18、rd: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).3.2.2 spike, vthe addition of a known amount of
19、 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 an analytical process. Matrix spiking is a pr
20、ocess 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 (alon
21、g 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 describes a technique for the addition of aknown amou
22、nt 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 original concentration in the sample arediscussed.
23、 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 method to a particular sample matrix, bydete
24、rmining 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, ormonitor
25、ing, 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 same or similar matrices over timemay indicat
26、e 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, including preservation and shipping of the
27、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 subsequent tothe addition of the spike.5.4 Special pr
28、ecautions 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
29、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 and the spiking technique. Whenenvironmental
30、ly 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 laboratory, should belabeled as a field spike in the
31、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 recovered from a spikedsample. One reason that
32、 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 differently than thebackground level of the analyte
33、. 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.5.6 This guide is also applicable to the pre
34、paration 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 mag
35、netic 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
36、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 and sample volumes used.6.3 MicropipettorsStai
37、nless 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.D5788 95 (2011)26.4 SyringesBorosil
38、icate 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 sample and to add larger volumes of spikings
39、olutions.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 shall be used in all spike preparations. Spe
40、ctrograde,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 met
41、hods 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 uns
42、pecified 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
43、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 available,different from that of the routine meth
44、od 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 utilized, theminimum criteria of each test m
45、ethod 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) beingperformed.7.3 MethanolSpectrograde, HPL
46、C 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 so
47、lutions 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
48、 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.Stability is demonstrated whenever the analyzed concentrationof a diluted spik
49、ing 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
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