ASTM D5810-96(2015)
(Guide)Standard Guide for Spiking into Aqueous Samples
Standard Guide for Spiking into Aqueous Samples 
SIGNIFICANCE AND USE
5.1 Matrix spiking is commonly used to determine the bias under specific analytical conditions, or the applicability of a test method to a particular sample matrix in that context, by determining the extent to which the spiked analyte or component is recovered from the sample matrix under these conditions. Reactions or interactions of the analyte or component of interest with the sample matrix may cause a significant positive or negative effect on recovery and may render the chosen analytical, or monitoring, process ineffectual for that sample matrix.
5.2 Matrix spiking can also be used to monitor the performance of a laboratory, individual instrument, or analyst as part of a regular quality assurance program. Changes in spike recoveries or recovery limits from the same or similar matrices over time may indicate variations in the quality of analytical results.
5.3 Spiking can be used to compare the recoveries of like spikes from reagent water samples and natural matrix samples (measured with and without spike) to distinguish between (1) unusual interference and (2) inherent method recovery and instability effects. This guide does not attempt to deal with the statistical significance of differences in spike recoveries from different matrices.
5.4 Special precautions shall be observed when nonlaboratory personnel perform spiking in the field. It is recommended that all spike preparation work be performed in a laboratory by experienced analysts so that the field operation consists solely of adding a prepared spiking solution to the sample matrix. Training of field personnel and validation of their spiking techniques are necessary to ensure that spikes are added accurately and reproducibly. Duplicate field spikes can be used to document the reproducibility of the technique. When environmentally labile compounds are used as spikes, the spiking solution shall be protected up to the point of use by appropriate means such as chilling, protection from sunlight and o...
SCOPE
1.1 This guide covers the general technique of “spiking” a broad range of materials into aqueous media. This guide will serve the analyst in preparing spiked samples for quality control purposes. Guidance is also provided to aid the analyst in calculating recoveries and interpreting results. It is the responsibility of the analyst to determine whether the procedures and materials described here are appropriate to the task at hand.
1.2 The procedures in this guide are focused on “matrix spike” preparation, analysis, and interpretation of results. The applicability of these procedures to the preparation of calibration standards, calibration check standards, laboratory control standards, reference materials, and other quality control materials by spiking is incidental. A sample (the matrix) is fortified (spiked) with the analyte of interest for a variety of analytical and quality control purposes. While the spiking of multiple sample portions is discussed, the method of standard additions is not covered.
1.3 This guide is intended for use in conjunction with the individual analytical test method that provides procedures for analysis of the analyte or component of interest. The test method is used to determine an analyte or component's background level and, again after spiking, its now elevated level. Each test method typically provides procedures not only for samples, but also for calibration standards or analytical control solutions, or both. These procedures include preparation, handling, storage, preservation, and analysis techniques. These procedures are applicable by extension, using the analyst's judgement on a case-by-case basis, to spiking solutions, and are not reiterated in this guide. See also Practice E200 for preparation and storage information.
1.4 These procedures apply only to analytes that are soluble in water at the concentration of the spike plus any background material, or to analytes soluble in...
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Designation: D5810 − 96 (Reapproved 2015)
Standard Guide for
Spiking into Aqueous Samples
This standard is issued under the fixed designation D5810; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope a homogeneous solution of analyte and sample. Meaningful
recovery data cannot be obtained if an aqueous solution or
1.1 This guide covers the general technique of “spiking” a
homogenoussuspensionoftheanalyteofinterestinthesample
broad range of materials into aqueous media. This guide will
cannot be attained. These procedures may be applicable to
serve the analyst in preparing spiked samples for quality
microbiologicalpreparationsifthehomogeneityofthesuspen-
control purposes. Guidance is also provided to aid the analyst
sioncanbeadequatelymaintainedthroughoutthecourseofthe
in calculating recoveries and interpreting results. It is the
analysis, for example, by mechanical agitation or stirring.
responsibility of the analyst to determine whether the proce-
dures and materials described here are appropriate to the task 1.5 Matrix spiking may be performed in the field or in the
at hand. laboratory,dependingonwhichpartoftheanalyticalprocessis
to be tested. Field spiking tests the recovery of the overall
1.2 The procedures in this guide are focused on “matrix
process, including preservation and shipping of the sample.
spike” preparation, analysis, and interpretation of results. The
Laboratoryspikingteststhelaboratoryprocessonly.Spikingof
applicability of these procedures to the preparation of calibra-
sample extracts, concentrates, or dilutions will test only that
tion standards, calibration check standards, laboratory control
portion of the process subsequent to addition of the spike.
standards, reference materials, and other quality control mate-
rials by spiking is incidental.Asample (the matrix) is fortified 1.6 The values stated in SI units are to be regarded as
(spiked) with the analyte of interest for a variety of analytical standard. No other units of measurement are included in this
and quality control purposes. While the spiking of multiple standard.
sample portions is discussed, the method of standard additions
1.7 This standard does not purport to address all of the
is not covered.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.3 This guide is intended for use in conjunction with the
priate safety and health practices and determine the applica-
individual analytical test method that provides procedures for
bility of regulatory limitations prior to use.
analysis of the analyte or component of interest. The test
method is used to determine an analyte or component’s
2. Referenced Documents
background level and, again after spiking, its now elevated
2.1 ASTM Standards:
level. Each test method typically provides procedures not only
D1129Terminology Relating to Water
for samples, but also for calibration standards or analytical
D1193Specification for Reagent Water
control solutions, or both. These procedures include
D3694Practices for Preparation of Sample Containers and
preparation, handling, storage, preservation, and analysis tech-
for Preservation of Organic Constituents
niques.Theseproceduresareapplicablebyextension,usingthe
D3856Guide for Management Systems in Laboratories
analyst’s judgement on a case-by-case basis, to spiking
Engaged in Analysis of Water
solutions, and are not reiterated in this guide. See also Practice
D4375Practice for Basic Statistics in Committee D19 on
E200 for preparation and storage information.
Water
1.4 Theseproceduresapplyonlytoanalytesthataresoluble
E200Practice for Preparation, Standardization, and Storage
in water at the concentration of the spike plus any background
of Standard and Reagent Solutions for ChemicalAnalysis
material, or to analytes soluble in a solvent that is itself
water-soluble. The system used in the later case must result in
3. Terminology
3.1 Definitions—For definitions of terms used in this guide,
refer to Terminology D1129.
This guide is under the jurisdiction ofASTM Committee D19 on Water and is
thedirectresponsibilityofSubcommitteeD19.02onQualitySystems,Specification,
and Statistics. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 15, 2015. Published December 2015. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1996. Last previous edition approved in 2011 as D5810–96 (2011). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D5810-96R15. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5810 − 96 (2015)
3.2 Definitions: 5.4 Special precautions shall be observed when nonlabora-
3.2.1 matrix spike, n—the quantity (mass) of a component tory personnel perform spiking in the field. It is recommended
(analyte) of interest that is added to a sample (matrix) in order thatallspikepreparationworkbeperformedinalaboratoryby
to test the bias as measured by recovery (of that component experienced analysts so that the field operation consists solely
under specific analytical conditions) and reported as percent of adding a prepared spiking solution to the sample matrix.
recovery (P). Training of field personnel and validation of their spiking
techniques are necessary to ensure that spikes are added
3.2.2 spike, v—the addition of a known amount of an
accuratelyandreproducibly.Duplicatefieldspikescanbeused
analyte of known identity to a measured volume of a sample
to document the reproducibility of the technique. When envi-
(from a specific matrix) to determine the efficiency with which
ronmentally labile compounds are used as spikes, the spiking
the added analyte can be “recovered” from (measured in) that
solutionshallbeprotecteduptothepointofusebyappropriate
matrix by the analytical system after exposure to a specific
meanssuchaschilling,protectionfromsunlightandoxygen,or
portionofananalyticalprocess.Matrixspikingisaprocessfor
chemical preservation.
accomplishing this. The precision and bias estimates from
several trials under specific analytical conditions represent the
NOTE1—Anyfieldspikedsample,ifknowntothelaboratory,shouldbe
measurement efficiency with which the analyte may be deter- labeledasafieldspikeinthefinalresultsreport.Also,wheneverpossible,
field spiking of volatile compounds should be avoided.
mined under these conditions.
5.5 It is often tacitly assumed that an analyte component is
3.2.3 spiking solution—the solution in which one or more
recovered from samples to approximately the same extent that
spikes are dissolved (along with any necessary preservatives).
a spike of the same analyte is recovered from a spiked sample.
This solution acts as a carrier to provide ease of measurement
One reason that this assumption may be incorrect is that the
and more rapid and thorough mixing of the spike into the
spike may not be bound up in the sample (for example, with
sample, as compared to adding the spike as a pure compound.
suspendedmatter)inthesamewaythatthenaturallyoccurring
analyte is bound in the sample. The spike may therefore be
4. Summary of Guide
recovered from the sample differently than the background
4.1 This guide describes a technique for the addition of a
level of the analyte. It is not good practice to correct analytical
known amount of an analyte to an aqueous sample.Appropri-
data using spike recoveries for this reason, as well as the fact
ate concentrations of the spike relative to the original concen-
that bias corrections can add variability. However, spike
tration in the sample are discussed. Applications of the tech-
recovery information should be reported along with related
nique and aids in the interpretation of results obtained are
sample analysis results.
described.
5.6 This guide is also applicable to the use of spikes for
5. Significance and Use quantification by the method of standard additions and to the
addition of surrogates and internal standards.
5.1 Matrix spiking is commonly used to determine the bias
under specific analytical conditions, or the applicability of a
6. Apparatus
test method to a particular sample matrix in that context, by
6.1 Pipetters—Plunger-actuated pipetters, to dispense small
determining the extent to which the spiked analyte or compo-
volumesofspikesolutions.Thesemustbecalibratedandtested
nent is recovered from the sample matrix under these condi-
carefully for repeatability before use.
tions. Reactions or interactions of the analyte or component of
interestwiththesamplematrixmaycauseasignificantpositive 6.2 Volumetric Transfer Pipets—Class A, used to deliver
or negative effect on recovery and may render the chosen knownvolumesofsampleandtoaddlargervolumesofspiking
analytical, or monitoring, process ineffectual for that sample solutions.
matrix.
6.3 Volumetric Flasks—Class A volumetric flasks may be
5.2 Matrix spiking can also be used to monitor the perfor- used to measure known volumes of sample.
mance of a laboratory, individual instrument, or analyst as part
6.4 Balance—An analytical (0.1-mg), semimicro (0.01-
of a regular quality assurance program. Changes in spike
mg), or micro (0.001-mg) balance.
recoveriesorrecoverylimitsfromthesameorsimilarmatrices
over time may indicate variations in the quality of analytical 7. Reagents
results.
7.1 Purity of Reagents—At a minimum, reagent grade
5.3 Spiking can be used to compare the recoveries of like chemicals shall be used in all spike preparations. Reagents of
spikes from reagent water samples and natural matrix samples thehighestavailablepurityshallbeusedforspikeanalytesand
(measured with and without spike) to distinguish between (1) demonstrated to be free of interfering substances for the
unusual interference and (2) inherent method recovery and subsequent tests to be performed. If possible, a primary
instability effects. This guide does not attempt to deal with the
standard grade shall be used. Unless otherwise indicated, it is
statistical significance of differences in spike recoveries from intended that all reagents conform to the specifications of the
different matrices. Committee onAnalytical Reagents of theAmerican Chemical
D5810 − 96 (2015)
Society. Other grades may be used, provided that the reagent importance to the successful measurement of spike recovery.
isofsufficientlyhighpuritytopermititsusewithoutadversely This is especially critical in samples containing suspended
affecting the bias and precision of subsequent determinations. sediment or volatile components.
Purchasedspikingsolutionsshallbedemonstratedtobefreeof
8.2 Sample containers shall be selected and prepared, and
substancesthatwouldinterferewithsubsequentanalysesbeing
samples shall be preserved in accordance with Practices
performed, and the supplier’s stated concentration shall be
D3694.
verified by analysis prior to use. Compensatory errors associ-
atedwithself-referencingshouldbepreventedbyusingspiking
9. Procedure
solutions of a standard originating from a source, when
9.1 Use relevant good laboratory practices in accordance
available, different from that of the routine method calibration
with Guide D3856 and Practice E200.
standards.
9.2 Performananalysisonatleastoneportionofthesample
7.2 Purity of Water—Unless otherwise indicated, references
to estimate the concentration of the component(s) of interest.
to water shall be understood to mean reagent water as defined
9.3 Use the result of this analysis to determine the appro-
by the individual test method to be used to analyze a sample
priate amount of spike and spiking solution to be added to the
after spiking. If more than one test method is to be used, the
sample. If this is not possible (such as when spiking in the
minimum criteria of each test method must be met. If test
field),estimatetheconcentrationsofthecomponentsofinterest
method reagent water specifications are not available, refer-
based on prior knowledge of the sample source.
ences to water shall be understood to mean reagent water as
9.3.1 To be of maximum value for quantification of the
defined by Type I of Specification D1193 and demonstrated to
analyte(s) or for the evaluation of method accuracy, the
be free of interfering substances for the test(s) being per-
concentration in the spiked sample should be at least double,
formed.
butideallynotoverfivetimes,theconcentrationoftheanalyte
7.3 Solvents—Spectroscopic, high-pressure liquid chroma-
in the unspiked sample, as long as the total analyte concentra-
tography(HPLC),orultrapuregrademethanolispreferablefor
tion can be brought within the test method’s dynamic range.
use as a solvent for relatively water-insoluble components in
Spike concentrations below this range lead to highly variable
most trace-organic analyses. Other water-soluble solvents may
spike recoveries, as described in Section 11. Higher spike
be useful as solvents for certain analytes. Most inorganic
concentrationsmaymasktheeffectthatrealinterferences,such
spiking solutions are prepared in water or dilute aqueous acid
as matrix effects, are having on the analyte at its background
solution. Solvents shall be checked before use by analysis for
levels,leadingtoover-optimisticestimatesofanalyterecovery.
interfering substances.
9.3.2 If the spiked component is not present in the sample,
7.4 Spiking Solutions—Spiking solutions of each analyte of
but is added only to validate the recovery of an analytical
interest are prepared individually or in combination, either
method, the concentration after spiking should be at least five
gravimetricallyorvolumetrically.Thepreservationandstorage
times the detection limit of the method or a concentration of
criteria found in the applicable analytical test method for its
interest to the data user, whichever is greater.
calibration or check standards apply likewise to spiking solu-
9.4 Determine the volume of the portion of sample to be
tions. The stability of a stored spiking solution should be
spiked, depending on such factors as the sample volume
verified routinely by the appropriate dilution of a portion of
required by the analytical method to be used, convenience of
spiking solution to the laboratory’s analyte concentration of
dilution factors, and amount of sample available.
interest. Stability is demonstrated whenever the analyzed
9.5 Prepare a spiking solution of suitable concentration
concentration of a dil
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: D5810 − 96 (Reapproved 2011) D5810 − 96 (Reapproved 2015)
Standard Guide for
Spiking into Aqueous Samples
This standard is issued under the fixed designation D5810; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide covers the general technique of “spiking” a broad range of materials into aqueous media. This guide will serve
the analyst in preparing spiked samples for quality control purposes. Guidance is also provided to aid the analyst in calculating
recoveries and interpreting results. It is the responsibility of the analyst to determine whether the procedures and materials
described here are appropriate to the task at hand.
1.2 The procedures in this guide are focused on “matrix spike” preparation, analysis, and interpretation of results. The
applicability of these procedures to the preparation of calibration standards, calibration check standards, laboratory control
standards, reference materials, and other quality control materials by spiking is incidental. A sample (the matrix) is fortified
(spiked) with the analyte of interest for a variety of analytical and quality control purposes. While the spiking of multiple sample
portions is discussed, the method of standard additions is not covered.
1.3 This guide is intended for use in conjunction with the individual analytical test method that provides procedures for analysis
of the analyte or component of interest. The test method is used to determine an analyte or component’s background level and,
again after spiking, its now elevated level. Each test method typically provides procedures not only for samples, but also for
calibration standards or analytical control solutions, or both. These procedures include preparation, handling, storage, preservation,
and analysis techniques. These procedures are applicable by extension, using the analyst’s judgement on a case-by-case basis, to
spiking solutions, and are not reiterated in this guide. See also Practice E200 for preparation and storage information.
1.4 These procedures apply only to analytes that are soluble in water at the concentration of the spike plus any background
material, or to analytes soluble in a solvent that is itself water-soluble. The system used in the later case must result in a
homogeneous solution of analyte and sample. Meaningful recovery data cannot be obtained if an aqueous solution or homogenous
suspension of the analyte of interest in the sample cannot be attained. These procedures may be applicable to microbiological
preparations if the homogeneity of the suspension can be adequately maintained throughout the course of the analysis, for example,
by mechanical agitation or stirring.
1.5 Matrix spiking may be performed in the field or in the laboratory, depending on which part of the analytical process is to
be tested. Field spiking tests the recovery of the overall process, including preservation and shipping of the sample. Laboratory
spiking tests the laboratory process only. Spiking of sample extracts, concentrates, or dilutions will test only that portion of the
process subsequent to addition of the spike.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D3694 Practices for Preparation of Sample Containers and for Preservation of Organic Constituents
This guide is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.02 on Quality Systems, Specification, and
Statistics.
Current edition approved May 1, 2011Dec. 15, 2015. Published June 2011December 2015. Originally approved in 1996. Last previous edition approved in 20062011 as
D5810 – 96 (2006).(2011). DOI: 10.1520/D5810-96R11.10.1520/D5810-96R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5810 − 96 (2015)
D3856 Guide for Management Systems in Laboratories Engaged in Analysis of Water
D4375 Practice for Basic Statistics in Committee D19 on Water
E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
3. Terminology
3.1 Definitions—For definitions of terms used in this guide, refer to Terminology D1129.
3.2 Definitions:
3.2.1 matrix spike, n—the quantity (mass) of a component (analyte) of interest that is added to a sample (matrix) in order to test
the bias as measured by recovery (of that component under specific analytical conditions) and reported as percent recovery (P).
3.2.2 spike, v—the addition of a known amount of an analyte of known identity to a measured volume of a sample (from a
specific matrix) to determine the efficiency with which the added analyte can be “recovered” from (measured in) that matrix by
the analytical system after exposure to a specific portion of an analytical process. Matrix spiking is a process for accomplishing
this. The precision and bias estimates from several trials under specific analytical conditions represent the measurement efficiency
with which the analyte may be determined under these conditions.
3.2.3 spiking solution—the solution in which one or more spikes are dissolved (along with any necessary preservatives). This
solution acts as a carrier to provide ease of measurement and more rapid and thorough mixing of the spike into the sample, as
compared to adding the spike as a pure compound.
4. Summary of Guide
4.1 This guide describes a technique for the addition of a known amount of an analyte to an aqueous sample. Appropriate
concentrations of the spike relative to the original concentration in the sample are discussed. Applications of the technique and aids
in the interpretation of results obtained are described.
5. Significance and Use
5.1 Matrix spiking is commonly used to determine the bias under specific analytical conditions, or the applicability of a test
method to a particular sample matrix in that context, by determining the extent to which the spiked analyte or component is
recovered from the sample matrix under these conditions. Reactions or interactions of the analyte or component of interest with
the sample matrix may cause a significant positive or negative effect on recovery and may render the chosen analytical, or
monitoring, process ineffectual for that sample matrix.
5.2 Matrix spiking can also be used to monitor the performance of a laboratory, individual instrument, or analyst as part of a
regular quality assurance program. Changes in spike recoveries or recovery limits from the same or similar matrices over time may
indicate variations in the quality of analytical results.
5.3 Spiking can be used to compare the recoveries of like spikes from reagent water samples and natural matrix samples
(measured with and without spike) to distinguish between (1) unusual interference and (2) inherent method recovery and instability
effects. This guide does not attempt to deal with the statistical significance of differences in spike recoveries from different
matrices.
5.4 Special precautions shall be observed when nonlaboratory personnel perform spiking in the field. It is recommended that
all spike preparation work be performed in a laboratory by experienced analysts so that the field operation consists solely of adding
a prepared spiking solution to the sample matrix. Training of field personnel and validation of their spiking techniques are
necessary to ensure that spikes are added accurately and reproducibly. Duplicate field spikes can be used to document the
reproducibility of the technique. When environmentally labile compounds are used as spikes, the spiking solution shall be
protected up to the point of use by appropriate means such as chilling, protection from sunlight and oxygen, or chemical
preservation.
NOTE 1—Any field spiked sample, if known to the laboratory, should be labeled 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 analyte component is recovered from samples to approximately the same extent that a
spike of the same analyte is recovered from a spiked sample. One reason that this assumption may be incorrect is that the spike
may not be bound up in the sample (for example, with suspended matter) in the same way that the naturally occurring analyte is
bound in the sample. The spike may therefore be recovered from the sample differently than the background level of the analyte.
It is not good practice to correct analytical data using spike recoveries for this reason, as well as the fact that bias corrections can
add variability. However, spike recovery information should be reported along with related sample analysis results.
5.6 This guide is also applicable to the use of spikes for quantification by the method of standard additions and to the addition
of surrogates and internal standards.
D5810 − 96 (2015)
6. Apparatus
6.1 Pipetters—Plunger-actuated pipetters, to dispense small volumes of spike solutions. These must be calibrated and tested
carefully for repeatability before use.
6.2 Volumetric Transfer Pipets—Class A, used to deliver known volumes of sample and to add larger volumes of spiking
solutions.
6.3 Volumetric Flasks—Class A volumetric flasks may be used to measure known volumes of sample.
6.4 Balance—An analytical (0.1-mg), semimicro (0.01- mg), or micro (0.001-mg) balance.
7. Reagents
7.1 Purity of Reagents—At a minimum, reagent grade chemicals shall be used in all spike preparations. Reagents of the highest
available purity shall be used for spike analytes and demonstrated to be free of interfering substances for the subsequent tests to
be performed. If possible, a primary standard grade shall be used. Unless otherwise indicated, it is intended that all reagents
conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society. Other grades may be
used, provided that the reagent is of sufficiently high purity to permit its use without adversely affecting the bias and precision of
subsequent determinations. Purchased spiking solutions shall be demonstrated to be free of substances that would interfere with
subsequent analyses being performed, and the supplier’s stated concentration shall be verified by analysis prior to use.
Compensatory errors associated with self-referencing should be prevented by using spiking solutions of a standard originating from
a source, when available, different from that of the routine method calibration standards.
7.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by
the individual test method to be used to analyze a sample after spiking. If more than one test method is to be used, the minimum
criteria of each test method must be met. If test method reagent water specifications are not available, references to water shall be
understood to mean reagent water as defined by Type I of Specification D1193 and demonstrated to be free of interfering substances
for the test(s) being performed.
7.3 Solvents—Spectroscopic, high-pressure liquid chromatography (HPLC), or ultrapure grade methanol is preferable for use as
a solvent for relatively water-insoluble components in most trace-organic analyses. Other water-soluble solvents may be useful as
solvents for certain analytes. Most inorganic spiking solutions are prepared in water or dilute aqueous acid solution. Solvents shall
be checked before use by analysis for interfering substances.
7.4 Spiking Solutions—Spiking solutions of each analyte of interest are prepared individually or in combination, either
gravimetrically or volumetrically. The preservation and storage criteria found in the applicable analytical test method for its
calibration or check standards apply likewise to spiking solutions. The stability of a stored spiking solution should be verified
routinely by the appropriate dilution of a portion of spiking solution to the laboratory’s analyte concentration of interest. Stability
is demonstrated whenever the analyzed concentration of a diluted spiking solution falls within the control limits for a routine
laboratory control sample of the same concentration. Where solubilities permit, stock spiking solutions may be prepared 25 to 100
times as concentrated as the working spike solution and diluted volumetrically to produce the working spike solution at the time
of use. In some cases, concentrated solutions may be stable for substantially longer periods than dilute solutions. Alternatively,
prepare spike or spiking solution fresh for each batch of samples.
8. Sampling
8.1 Although sampling methodology is beyond the scope of this guide, a properly split or duplicate sample is of utmost
importance to the successful measurement of spike recovery. This is especially critical in samples containing suspended sediment
or volatile components.
8.2 Sample containers shall be selected and prepared, and samples shall be preserved in accordance with Practices D3694.
9. Procedure
9.1 Use relevant good laboratory practices in accordance with Guide D3856 and Practice E200.
9.2 Perform an analysis on at least one portion of the sample to estimate the concentration of the component(s) of interest.
9.3 Use the result of this analysis to determine the appropriate amount of spike and spiking solution to be added to the sample.
If this is not possible (such as when spiking in the field), estimate the concentrations of the components of interest based on prior
knowledg
...
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