ASTM D5810-96(2006)
(Guide)Standard Guide for Spiking into Aqueous Samples
Standard Guide for Spiking into Aqueous Samples
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 E 200 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 the standard.
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.
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Designation:D5810–96 (Reapproved 2006)
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-
1.5 Matrix spiking may be performed in the field or in the
dures and materials described here are appropriate to the task
laboratory,dependingonwhichpartoftheanalyticalprocessis
at hand.
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-
1.6 The values stated in SI units are to be regarded as the
rials by spiking is incidental.Asample (the matrix) is fortified
standard.
(spiked) with the analyte of interest for a variety of analytical
1.7 This standard does not purport to address all of the
and quality control purposes. While the spiking of multiple
safety concerns, if any, associated with its use. It is the
sample portions is discussed, the method of standard additions
responsibility of the user of this standard to establish appro-
is not covered.
priate safety and health practices and determine the applica-
1.3 This guide is intended for use in conjunction with the
bility of regulatory limitations prior to use.
individual analytical test method that provides procedures for
analysis of the analyte or component of interest. The test
2. Referenced Documents
method is used to determine an analyte or component’s
2.1 ASTM Standards:
background level and, again after spiking, its now elevated
D1129 Terminology Relating to Water
level. Each test method typically provides procedures not only
D1193 Specification for Reagent Water
for samples, but also for calibration standards or analytical
D3694 Practices for Preparation of Sample Containers and
control solutions, or both. These procedures include prepara-
for Preservation of Organic Constituents
tion, handling, storage, preservation, and analysis techniques.
D3856 Guide for Good Laboratory Practices in Laborato-
These procedures are applicable by extension, using the
ries Engaged in Sampling and Analysis of Water
analyst’s judgement on a case-by-case basis, to spiking solu-
D4375 Practice for Basic Statistics in Committee D19 on
tions, and are not reiterated in this guide. See also Practice
Water
E200 for preparation and storage information.
E200 Practice for Preparation, Standardization, and Storage
1.4 Theseproceduresapplyonlytoanalytesthataresoluble
of Standard and Reagent Solutions for Chemical Analysis
in water at the concentration of the spike plus any background
material, or to analytes soluble in a solvent that is itself
3. Terminology
water-soluble. The system used in the later case must result in
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
the direct responsibility of Subcommittee D19.02 on General Specifications,
Technical Resources, and Statistical Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Aug. 15, 2006. Published August 2006. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1996. Last previous edition approved in 2001 as D5810–96 (2001). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D5810-96R06. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5810–96 (2006)
3.2 Definitions of Terms Specific to This Standard: Training of field personnel and validation of their spiking
3.2.1 matrix spike, n—the quantity (mass) of a component techniques are necessary to ensure that spikes are added
(analyte) of interest that is added to a sample (matrix) in order accuratelyandreproducibly.Duplicatefieldspikescanbeused
to test the bias as measured by recovery (of that component to document the reproducibility of the technique. When envi-
under specific analytical conditions) and reported as percent ronmentally labile compounds are used as spikes, the spiking
recovery (P). solutionshallbeprotecteduptothepointofusebyappropriate
3.2.2 spike, v—the addition of a known amount of an meanssuchaschilling,protectionfromsunlightandoxygen,or
analyte of known identity to a measured volume of a sample chemical preservation.
(from a specific matrix) to determine the efficiency with which
NOTE 1—Anyfieldspikedsample,ifknowntothelaboratory,shouldbe
the added analyte can be “recovered” from (measured in) that
labeledasafieldspikeinthefinalresultsreport.Also,wheneverpossible,
matrix by the analytical system after exposure to a specific
field spiking of volatile compounds should be avoided.
portionofananalyticalprocess.Matrixspikingisaprocessfor
5.5 It is often tacitly assumed that an analyte component is
accomplishing this. The precision and bias estimates from
recovered from samples to approximately the same extent that
several trials under specific analytical conditions represent the
a spike of the same analyte is recovered from a spiked sample.
measurement efficiency with which the analyte may be deter-
One reason that this assumption may be incorrect is that the
mined under these conditions.
spike may not be bound up in the sample (for example, with
3.2.3 spiking solution—the solution in which one or more
suspendedmatter)inthesamewaythatthenaturallyoccurring
spikes are dissolved (along with any necessary preservatives).
analyte is bound in the sample. The spike may therefore be
This solution acts as a carrier to provide ease of measurement
recovered from the sample differently than the background
and more rapid and thorough mixing of the spike into the
level of the analyte. It is not good practice to correct analytical
sample, as compared to adding the spike as a pure compound.
data using spike recoveries for this reason, as well as the fact
that bias corrections can add variability. However, spike
4. Summary of Guide
recovery information should be reported along with related
4.1 This guide describes a technique for the addition of a
sample analysis results.
known amount of an analyte to an aqueous sample.Appropri-
5.6 This guide is also applicable to the use of spikes for
ate concentrations of the spike relative to the original concen-
quantification by the method of standard additions and to the
tration in the sample are discussed. Applications of the tech-
addition of surrogates and internal standards.
nique and aids in the interpretation of results obtained are
described.
6. Apparatus
6.1 Pipetters—Plunger-actuated pipetters, to dispense small
5. Significance and Use
volumesofspikesolutions.Thesemustbecalibratedandtested
5.1 Matrix spiking is commonly used to determine the bias
carefully for repeatability before use.
under specific analytical conditions, or the applicability of a
6.2 Volumetric Transfer Pipets—Class A, used to deliver
test method to a particular sample matrix in that context, by
knownvolumesofsampleandtoaddlargervolumesofspiking
determining the extent to which the spiked analyte or compo-
solutions.
nent is recovered from the sample matrix under these condi-
6.3 Volumetric Flasks—Class A volumetric flasks may be
tions. Reactions or interactions of the analyte or component of
used to measure known volumes of sample.
interestwiththesamplematrixmaycauseasignificantpositive
6.4 Balance—An analytical (0.1-mg), semimicro (0.01-
or negative effect on recovery and may render the chosen
mg), or micro (0.001-mg) balance.
analytical, or monitoring, process ineffectual for that sample
matrix.
7. Reagents
5.2 Matrix spiking can also be used to monitor the perfor-
7.1 Purity of Reagents—At a minimum, reagent grade
mance of a laboratory, individual instrument, or analyst as part
chemicals shall be used in all spike preparations. Reagents of
of a regular quality assurance program. Changes in spike
thehighestavailablepurityshallbeusedforspikeanalytesand
recoveriesorrecoverylimitsfromthesameorsimilarmatrices
demonstrated to be free of interfering substances for the
over time may indicate variations in the quality of analytical
subsequent tests to be performed. If possible, a primary
results.
standard grade shall be used. Unless otherwise indicated, it is
5.3 Spiking can be used to compare the recoveries of like
intended that all reagents conform to the specifications of the
spikes from reagent water samples and natural matrix samples
Committee onAnalytical Reagents of theAmerican Chemical
(measured with and without spike) to distinguish between (1)
Society. Other grades may be used, provided that the reagent
unusual interference and (2) inherent method recovery and
isofsufficientlyhighpuritytopermititsusewithoutadversely
instability effects. This guide does not attempt to deal with the
affecting the bias and precision of subsequent determinations.
statistical significance of differences in spike recoveries from
different matrices.
5.4 Special precautions shall be observed when nonlabora-
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
tory personnel perform spiking in the field. It is recommended
listed by the American Chemical Society, see Analar Standards for Laboratory
thatallspikepreparationworkbeperformedinalaboratoryby
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
experienced analysts so that the field operation consists solely
and National Formulary,U.S.PharmaceuticalConvention,Inc.(USPC),Rockville,
of adding a prepared spiking solution to the sample matrix. MD.
D5810–96 (2006)
Purchasedspikingsolutionsshallbedemonstratedtobefreeof 9.2 Performananalysisonatleastoneportionofthesample
substancesthatwouldinterferewithsubsequentanalysesbeing to estimate the concentration of the component(s) of interest.
performed, and the supplier’s stated concentration shall be
9.3 Use the result of this analysis to determine the appro-
verified by analysis prior to use. Compensatory errors associ-
priate amount of spike and spiking solution to be added to the
atedwithself-referencingshouldbepreventedbyusingspiking
sample. If this is not possible (such as when spiking in the
solutions of a standard originating from a source, when
field),estimatetheconcentrationsofthecomponentsofinterest
available, different from that of the routine method calibration
based on prior knowledge of the sample source.
standards.
9.3.1 To be of maximum value for quantification of the
7.2 Purity of Water—Unlessotherwiseindicated,references
analyte(s) or for the evaluation of method accuracy, the
to water shall be understood to mean reagent water as defined
concentration in the spiked sample should be at least double,
by the individual test method to be used to analyze a sample
but ideally not over five times, the concentration of the analyte
after spiking. If more than one test method is to be used, the
in the unspiked sample, as long as the total analyte concentra-
minimum criteria of each test method must be met. If test
tion can be brought within the test method’s dynamic range.
method reagent water specifications are not available, refer-
Spike concentrations below this range lead to highly variable
ences to water shall be understood to mean reagent water as
spike recoveries, as described in Section 11. Higher spike
defined by Type I of Specification D1193 and demonstrated to
concentrationsmaymasktheeffectthatrealinterferences,such
be free of interfering substances for the test(s) being per-
as matrix effects, are having on the analyte at its background
formed.
levels,leadingtoover-optimisticestimatesofanalyterecovery.
7.3 Solvents—Spectroscopic, high-pressure liquid chroma-
9.3.2 If the spiked component is not present in the sample,
tography(HPLC),orultrapuregrademethanolispreferablefor
but is added only to validate the recovery of an analytical
use as a solvent for relatively water-insoluble components in
method, the concentration after spiking should be at least five
most trace-organic analyses. Other water-soluble solvents may
times the detection limit of the method or a concentration of
be useful as solvents for certain analytes. Most inorganic
interest to the data user, whichever is greater.
spiking solutions are prepared in water or dilute aqueous acid
solution. Solvents shall be checked before use by analysis for 9.4 Determine the volume of the portion of sample to be
interfering substances. spiked, depending on such factors as the sample volume
7.4 Spiking Solutions—Spiking solutions of each analyte of required by the analytical method to be used, convenience of
interest are prepared individually or in combination, either
dilution factors, and amount of sample available.
gravimetricallyorvolumetrically.Thepreservationandstorage
9.5 Prepare a spiking solution of suitable concentration
criteria found in the applicable analytical test method for its
using the appropriate solvent as described in 7.4.
calibration or check standards apply likewise to spiking solu-
9.5.1 Pertinent factors in determining the appropriate con-
tions. The stability of a stored spiking solution should be
centration of the spiking solution are as
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