1、Designation: D5810 96 (Reapproved 2015)Standard Guide forSpiking into Aqueous Samples1This standard is issued under the fixed designation D5810; 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
2、 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” abroad range of materials into aqueous media. This guide willserve the analyst in preparing
3、 spiked samples for qualitycontrol purposes. Guidance is also provided to aid the analystin calculating recoveries and interpreting results. It is theresponsibility of the analyst to determine whether the proce-dures and materials described here are appropriate to the taskat hand.1.2 The procedures
4、in this guide are focused on “matrixspike” preparation, analysis, and interpretation of results. 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 s
5、piking is incidental. A sample (the matrix) is fortified(spiked) with the analyte of interest for a variety of analyticaland quality control purposes. While the spiking of multiplesample portions is discussed, the method of standard additionsis not covered.1.3 This guide is intended for use in conju
6、nction with theindividual analytical 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
7、not onlyfor samples, but also for 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 spikin
8、gsolutions, and are not reiterated 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-
9、soluble. The system used in the later case must result ina homogeneous solution of analyte and sample. Meaningfulrecovery data cannot be obtained if an aqueous solution orhomogenous suspension of the analyte of interest in the samplecannot be attained. These procedures may be applicable tomicrobiolo
10、gical preparations if the homogeneity of the suspen-sion can be adequately maintained throughout the course of theanalysis, for example, by mechanical agitation or stirring.1.5 Matrix spiking may be performed in the field or in thelaboratory, depending on which part of the analytical process isto be
11、 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 the process subsequent to addition of the spike
12、.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 theresponsibility of the user of this standard to establish app
13、ro-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 Preparation of Sample Containers andfor Preservation of
14、 Organic ConstituentsD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD4375 Practice for Basic Statistics in Committee D19 onWaterE200 Practice for Preparation, Standardization, and Storageof Standard and Reagent Solutions for Chemical Analysis3. Terminology3.1 Definitio
15、nsFor definitions of terms used in this guide,refer to Terminology D1129.1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.02 on Quality Systems, Specification,and Statistics.Current edition approved Dec. 15, 2015. Published Dece
16、mber 2015. Originallyapproved in 1996. Last previous edition approved in 2011 as D5810 96 (2011).DOI: 10.1520/D5810-96R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, ref
17、er 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 States13.2 Definitions:3.2.1 matrix spike, nthe quantity (mass) of a component(analyte) of interest that is added to a sample (matri
18、x) in orderto test the 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 ananalyte of known identity to a measured volume of a sample(from a specific matrix) to determine the effici
19、ency 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 process foraccomplishing this. The precision and bias estimates fromseveral trials under specific analytical co
20、nditions 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 any necessary preservatives).This solution acts as a carrier to provide ease of measurementand more ra
21、pid 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 an analyte to an aqueous sample. Appropri-ate concentrations of the spike relative to the original conc
22、en-tration in the sample are discussed. Applications of the tech-nique and aids in the interpretation of results obtained aredescribed.5. Significance and Use5.1 Matrix spiking is commonly used to determine the biasunder specific analytical conditions, or the applicability of atest method to a parti
23、cular sample matrix in that context, bydetermining the extent to which the spiked analyte or compo-nent is recovered from the sample matrix under these condi-tions. Reactions or interactions of the analyte or component ofinterest with the sample matrix may cause a significant positiveor negative eff
24、ect on recovery and may render the chosenanalytical, or monitoring, process ineffectual for that samplematrix.5.2 Matrix spiking can also be used to monitor the perfor-mance of a laboratory, individual instrument, or analyst as partof a regular quality assurance program. Changes in spikerecoveries o
25、r recovery limits from the same or similar matricesover time may indicate variations in the quality of analyticalresults.5.3 Spiking can be used to compare the recoveries of likespikes from reagent water samples and natural matrix samples(measured with and without spike) to distinguish between (1)un
26、usual interference and (2) inherent method recovery andinstability effects. This guide does not attempt to deal with thestatistical significance of differences in spike recoveries fromdifferent matrices.5.4 Special precautions shall be observed when nonlabora-tory personnel perform spiking in the fi
27、eld. 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 field personnel and validation of their spikingtechniques are necessary to ensur
28、e that spikes are addedaccurately and reproducibly. Duplicate field spikes can be usedto document the reproducibility of the technique. When envi-ronmentally labile compounds are used as spikes, the spikingsolution shall be protected up to the point of use by appropriatemeans such as chilling, prote
29、ction from sunlight and oxygen, orchemical preservation.NOTE 1Any field spiked sample, if known to the laboratory, 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 an analy
30、te component isrecovered from samples to approximately the same extent thata spike of the same analyte is recovered from a spiked sample.One reason that this assumption may be incorrect is that thespike may not be bound up in the sample (for example, withsuspended matter) in the same way that the na
31、turally occurringanalyte is bound in the sample. The spike may therefore berecovered from the sample differently than the backgroundlevel of the analyte. It is not good practice to correct analyticaldata using spike recoveries for this reason, as well as the factthat bias corrections can add variabi
32、lity. However, spikerecovery information should be reported along with relatedsample analysis results.5.6 This guide is also applicable to the use of spikes forquantification by the method of standard additions and to theaddition of surrogates and internal standards.6. Apparatus6.1 PipettersPlunger-
33、actuated pipetters, to dispense smallvolumes of spike solutions.These must be calibrated and testedcarefully for repeatability before use.6.2 Volumetric Transfer PipetsClass A, used to deliverknown volumes of sample and to add larger volumes of spikingsolutions.6.3 Volumetric FlasksClass A volumetri
34、c flasks may beused to measure known volumes of sample.6.4 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. Reagents ofthe highest available purity shall be u
35、sed for spike analytes anddemonstrated to be free of interfering substances for thesubsequent tests to be performed. If possible, a primarystandard grade shall be used. Unless otherwise indicated, it isintended that all reagents conform to the specifications of theCommittee on Analytical Reagents of
36、 the American ChemicalD5810 96 (2015)2Society.3Other grades may be used, provided that the reagentis of sufficiently high purity to permit its use without adverselyaffecting the bias and precision of subsequent determinations.Purchased spiking solutions shall be demonstrated to be free ofsubstances
37、that would interfere with subsequent analyses beingperformed, and the suppliers stated concentration shall beverified by analysis prior to use. Compensatory errors associ-ated with self-referencing should be prevented by using spikingsolutions of a standard originating from a source, whenavailable,
38、different from that of the routine method calibrationstandards.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 used,
39、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 water asdefined by Type I of Specification D1193 and demonstrated tobe free of interfering substances for the test(s) being per-
40、formed.7.3 SolventsSpectroscopic, high-pressure liquid chroma-tography (HPLC), or ultrapure grade methanol is preferable foruse as a solvent for relatively water-insoluble components inmost trace-organic analyses. Other water-soluble solvents maybe useful as solvents for certain analytes. Most inorg
41、anicspiking solutions are prepared in water or dilute aqueous acidsolution. Solvents shall be checked before use by analysis forinterfering substances.7.4 Spiking SolutionsSpiking solutions of each analyte ofinterest are prepared individually or in combination, eithergravimetrically or volumetricall
42、y. 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 should beverified routinely by the appropriate dilution of a portion ofspiking solution to the
43、 laboratorys analyte concentration ofinterest. Stability is demonstrated whenever the analyzedconcentration of a diluted spiking solution falls within thecontrol limits for a routine laboratory control sample of thesame concentration. Where solubilities permit, stock spikingsolutions may be prepared
44、 25 to 100 times as concentrated asthe working spike solution and diluted volumetrically toproduce the working spike solution at the time of use. In somecases, concentrated solutions may be stable for substantiallylonger periods than dilute solutions. Alternatively, preparespike or spiking solution
45、fresh for each batch of samples.8. Sampling8.1 Although sampling methodology is beyond the scope ofthis guide, a properly split or duplicate sample is of utmostimportance to the successful measurement of spike recovery.This is especially critical in samples containing suspendedsediment or volatile c
46、omponents.8.2 Sample containers shall be selected and prepared, andsamples shall be preserved in accordance with PracticesD3694.9. Procedure9.1 Use relevant good laboratory practices in accordancewith Guide D3856 and Practice E200.9.2 Perform an analysis on at least one portion of the sampleto estim
47、ate the concentration of the component(s) of interest.9.3 Use the result of this analysis to determine the appro-priate amount of spike and spiking solution to be added to thesample. If this is not possible (such as when spiking in thefield), estimate the concentrations of the components of interest
48、based on prior knowledge of the sample source.9.3.1 To be of maximum value for quantification of theanalyte(s) or for the evaluation of method accuracy, theconcentration in the spiked sample should be at least double,but ideally not over five times, the concentration of the analytein the unspiked sa
49、mple, as long as the total analyte concentra-tion can be brought within the test methods dynamic range.Spike concentrations below this range lead to highly variablespike recoveries, as described in Section 11. Higher spikeconcentrations may mask the effect that real interferences, suchas matrix effects, are having on the analyte at its backgroundlevels, leading to over-optimistic estimates of analyte recovery.9.3.2 If the spiked component is not present in the sample,but is added only to validate the recovery of an analyticalmethod, the concentration after spiking
