ASTM D5788-95(2005)
(Guide)Standard Guide for Spiking Organics into Aqueous Samples
Standard Guide for Spiking Organics into Aqueous Samples
SCOPE
1.1 This guide covers the general technique of "spiking" aqueous samples with organic analytes or components. It is intended to be applicable to a broad range of organic materials in aqueous media. Although the specific details and handling procedures required for all types of compounds are not described, this general approach is given to serve as a guideline to the analyst in accurately preparing spiked samples for subsequent analysis or comparison. 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 methods and materials cited here are compatible with the analytes of interest.
1.2 The procedures in this guide are focused on "matrix spike" preparation, analysis, results, and interpretation. 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 test 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 homogeneous suspension of the analyte of interest in the sample cannot be attained.
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 the addition of the spike.
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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.
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Designation:D5788–95 (Reapproved 2005)
Standard Guide for
Spiking Organics into Aqueous Samples
This standard is issued under the fixed designation D5788; 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 tions, and are not reiterated in this guide. See also Practice
E200 for preparation and storage information.
1.1 This guide covers the general technique of “spiking”
1.4 Theseproceduresapplyonlytoanalytesthataresoluble
aqueous samples with organic analytes or components. It is
in water at the concentration of the spike plus any background
intended to be applicable to a broad range of organic materials
material, or to analytes soluble in a solvent that is itself
in aqueous media. Although the specific details and handling
water-soluble. The system used in the later case must result in
procedures required for all types of compounds are not
a homogeneous solution of analyte and sample. Meaningful
described,thisgeneralapproachisgiventoserveasaguideline
recovery data cannot be obtained if an aqueous solution or
to the analyst in accurately preparing spiked samples for
homogeneous suspension of the analyte of interest in the
subsequent analysis or comparison. Guidance is also provided
sample cannot be attained.
to aid the analyst in calculating recoveries and interpreting
1.5 Matrix spiking may be performed in the field or in the
results. It is the responsibility of the analyst to determine
laboratory,dependingonwhichpartoftheanalyticalprocessis
whether the methods and materials cited here are compatible
to be tested. Field spiking tests the recovery of the overall
with the analytes of interest.
process, including preservation and shipping of the sample.
1.2 The procedures in this guide are focused on “matrix
Laboratoryspikingteststhelaboratoryprocessonly.Spikingof
spike” preparation, analysis, results, and interpretation. The
sample extracts, concentrates, or dilutions will test only that
applicability of these procedures to the preparation of calibra-
portion of the process subsequent to the addition of the spike.
tion standards, calibration check standards, laboratory control
1.6 The values stated in SI units are to be regarded as the
standards, reference materials, and other quality control mate-
standard. The values given in parentheses are for information
rials by spiking is incidental.Asample (the matrix) is fortified
only.
(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 test portions is discussed, the method of standard
responsibility of the user of this standard to establish appro-
additions 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
Water
This guide is under the jurisdiction ofASTM Committee D19 on Water and is
the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
Organic Substances in Water. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2005. Published January 2006. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1995. Last previous edition approved in 2001 as D5788–95 (2001). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D5788-95R05. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5788–95 (2005)
E200 Practice for Preparation, Standardization, and Storage may be considered a measure of the stability of the analytes in
of Standard and Reagent Solutions for Chemical Analysis the matrix. Laboratory spiking tests the laboratory process
only.Spikingofsampleextracts,concentrates,ordilutionswill
3. Terminology be reflective of only that portion of the process subsequent to
the addition of the spike.
3.1 Definitions—For definitions of terms used in this guide,
5.4 Special precautions shall be observed when nonlabora-
refer to Terminology D1129.
tory personnel perform spiking in the field. It is recommended
3.2 Definitions of Terms Specific to This Standard:
thatallspikepreparationworkbeperformedinalaboratoryby
3.2.1 matrix spike, n—the quantity (mass) of a component
experienced analysts so that the field operation consists solely
(analyte) of interest which is added to a sample (matrix) in
of adding a prepared spiking solution to the sample matrix.
order to test bias as measured by recovery (of that component
Training of field personnel and validation of their spiking
under specific analytical conditions) and reported as percent
techniques are necessary to ensure that spikes are added
recovery (P).
accurately and reproducibly. Consistent and acceptable recov-
3.2.2 spike, v—the addition of a known amount of an
eries from duplicate field spikes can be used to document the
analyte of known identity to a measured volume of a sample
reproducibility of sampling and the spiking technique. When
(from a specific matrix) to determine the efficiency with which
environmentally labile compounds are used as spikes, the
the added analyte can be 88recovered” from (measured in) that
spiking solution shall be protected up to the time of use by
matrix by the analytical system after exposure to a specific
appropriate means such as chilling, protection from sunlight
portionofananalyticalprocess.Matrixspikingisaprocessfor
and oxygen, or chemical preservation.
accomplishing this. The precision and bias estimates from
several trials under specific analytical conditions represent the
NOTE 1—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.
3.2.3 spiking solution—the solution in which one or more
5.5 It is often tacitly assumed that the analyte component is
spikes are dissolved (along with any necessary preservatives).
recovered from the sample to approximately the same extent
This solution acts as a carrier to provide ease of measurement
that a spike of the same analyte is recovered from a spiked
and more rapid and thorough mixing of the spike into the
sample. One reason that this assumption may be incorrect is
sample, as compared to adding the spike as a pure compound.
thatthespikemaynotbeboundupinthesample(forexample,
with suspended matter) in the same way that the naturally
4. Summary of Guide
occurring analyte is bound in the sample. The spike may
therefore be recovered from the sample differently than the
4.1 This guide describes a technique for the addition of a
known amount of an organic analyte to an aqueous sample. background level of the analyte. For this reason, as well as the
Instructions are given to help prevent loss of volatile analytes fact that bias corrections can add variability, it is not good
in the sample headspace and to provide a homogeneous practicetocorrectanalyticaldatausingspikerecoveries.Spike
solutionforsubsequentanalysis.Appropriateconcentrationsof recovery information should, however, be reported along with
thespikerelativetotheoriginalconcentrationinthesampleare the related sample analysis results.
discussed. Applications of the technique and aids in the 5.6 This guide is also applicable to the preparation and use
interpretation of results obtained are described. ofspikesforquantificationbythemethodofstandardadditions
and to the addition of surrogates and internal standards.
5. Significance and Use
6. Apparatus
5.1 Matrix spiking of samples is commonly used to deter-
mine the bias under specific analytical conditions, or the 6.1 StirringApparatus—Borosilicateglassbeads,4to6mm
in diameter, or small TFE-coated magnetic stirring bars. A
applicability of a test method to a particular sample matrix, by
determining the extent to which the added spike is recovered small non-heating variable-speed magnetic stirrer is recom-
from the sample matrix under these conditions. Reactions or mended for use with the stirring bar.
interactions of the analyte or component of interest with the 6.2 Microsyringes—Standard gas chromatographic mi-
sample matrix may cause a significant positive or negative crosyringes of borosilicate glass with stainless steel needles,
effect on recovery and may render the chosen analytical, or suitableforinjectionofspikingsolutionsthroughaTFE-coated
monitoring, process ineffectual for that sample matrix. silicone septum. The TFE-tipped plungers may be contami-
5.2 Matrix spiking of samples can also be used to monitor nated by certain analytes. If this is determined to be likely, a
the performance of a laboratory, individual instrument, or syringe may be dedicated to a single process, or a plain-tipped
analystaspartofaregularqualityassuranceprogram.Changes stainless steel plunger may be used to avoid cross-
inspikerecoveriesfromthesameorsimilarmatricesovertime contamination. Sizes from 10 to 500 µL are appropriate,
mayindicatevariationsinthequalityofanalysesandanalytical depending on the concentration and sample volumes used.
results. 6.3 Micropipettors—Stainless steel micropipettors with dis-
5.3 Spiking of samples may be performed in the field or in posable glass tips are preferable to syringes for introduction of
thelaboratory,dependingonwhatpartoftheanalyticalprocess spiking solutions into open sample containers, since they
is to be tested. Field spiking tests the recovery of the overall deliver more reproducibly and are less prone to cross-
process,includingpreservationandshippingofthesampleand contamination. Sizes from 5 to 200 µL are appropriate.
D5788–95 (2005)
6.4 Syringes—Borosilicateglasssyringeswithdemountable 7.4 Spiking Solutions—Spiking solutions of each analyte of
stainless steel needles may be used to measure volumes of interest are prepared individually or in combination, either
samples(spikedorunspiked)tobeinjectedintopurge-and-trap gravimetrically or volumetrically, correcting for density (for
sample introduction systems. liquid or solution standards). The preservation and storage
6.5 Volumetric Transfer Pipets—Class A, used to deliver criteria found in the applicable analytical test method for its
knownvolumesofsampleandtoaddlargervolumesofspiking calibration or check standards apply likewise to spiking solu-
solutions. tions.Thestabilityofastoredspikingsolutionshallbeverified
6.6 Volumetric Flasks—Class A volumetric flasks may be routinely by the appropriate dilution of a portion of spiking
used to measure known volumes of sample. solution to the laboratory’s analyte concentration of interest.
6.7 Balance—An analytical (0.1-mg), semimicro (0.01- Stability is demonstrated whenever the analyzed concentration
mg), or micro (0.001-mg) balance. 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 are custom-
7. Reagents
arily prepared 25 to 1000 times as concentrated as the working
7.1 Purity of Reagents—At a minimum, reagent grade
spiking solution, and are diluted volumetrically to produce the
chemicalsshallbeusedinallspikepreparations.Spectrograde,
working spiking solution at the time of use. In some cases,
high-pressure liquid chromatography (HPLC) grade, pesticide
concentrated solutions may be stable at 4°C for substantially
grade, or ultrapure grade solvents shall be used to prepare
longer periods than dilute solutions. Alternatively, prepare
spikingsolutions.Reagentsofthehighestavailablepurityshall
spike or spiking solution fresh for each batch of samples.
be used for spike analytes and demonstrated to be free of
interfering substances for the subsequent test methods to be
8. Sampling
performed. If possible, a primary standard grade shall be used.
8.1 Although sampling methodology is beyond the scope of
Unless otherwise indicated, it is intended that all reagents
this guide, a properly split or duplicate sample is of utmost
conform to the specifications of the Committee on Analytical
importance to the successful measurement of spike recovery.
Reagents of the American Chemical Society. Other grades
This is especially critical in samples containing suspended
maybeused,provided(1)thatreagentpurityisunspecifiedand
sediment or volatile analytes.
(2) that it is first ascertained that the reagent is of sufficiently
8.2 Sample containers shall be selected and prepared, and
high purity to permit its use without adversely affecting the
samplesshallbepreservedinaccordancewithPracticeD3694.
bias and precision of subsequent determinations. Purchased
spikingsolutionsshallbedemonstratedtobefreeofsubstances
9. Procedure
thatwouldinterferewithsubsequentanalysesbeingperformed,
9.1 Use relevant good laboratory practices in accordance
and the supplier’s stated concentration shall be verified by
with Guide D3856 and Practice E200.
analysis prior to use. Compensatory errors associated with
9.2 Nonvolatile Compounds—Except for volatile analytes,
self-referencingshouldbepreventedbyusingspikingsolutions
this category includes all analytes or components of interest.
of a standard originating from a source, when available,
Semi-volatile compounds, for which volatility is not a concern
different from
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