ASTM D5788-95(2001)

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An American National Standard
Designation:D 5788–95 (Reapproved 2001)
Standard Guide for
Spiking Organics into Aqueous Samples
This standard is issued under the fixed designation D 5788; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope water-soluble. The system used in the later case must result in
a homogeneous solution of analyte and sample. Meaningful
1.1 This guide covers the general technique of “spiking”
recovery data cannot be obtained if an aqueous solution or
aqueous samples with organic analytes or components. It is
homogeneous suspension of the analyte of interest in the
intended to be applicable to a broad range of organic materials
sample cannot be attained.
in aqueous media. Although the specific details and handling
1.5 Matrix spiking may be performed in the field or in the
procedures required for all types of compounds are not
laboratory,dependingonwhichpartoftheanalyticalprocessis
described,thisgeneralapproachisgiventoserveasaguideline
to be tested. Field spiking tests the recovery of the overall
to the analyst in accurately preparing spiked samples for
process, including preservation and shipping of the sample.
subsequent analysis or comparison. Guidance is also provided
Laboratoryspikingteststhelaboratoryprocessonly.Spikingof
to aid the analyst in calculating recoveries and interpreting
sample extracts, concentrates, or dilutions will test only that
results. It is the responsibility of the analyst to determine
portion of the process subsequent to the addition of the spike.
whether the methods and materials cited here are compatible
1.6 The values stated in SI units are to be regarded as the
with the analytes of interest.
standard. The values given in parentheses are for information
1.2 The procedures in this guide are focused on “matrix
only.
spike” preparation, analysis, results, and interpretation. The
1.7 This standard does not purport to address all of the
applicability of these procedures to the preparation of calibra-
safety concerns, if any, associated with its use. It is the
tion standards, calibration check standards, laboratory control
responsibility of the user of this standard to establish appro-
standards, reference materials, and other quality control mate-
priate safety and health practices and determine the applica-
rials by spiking is incidental.Asample (the matrix) is fortified
bility of regulatory limitations prior to use.
(spiked) with the analyte of interest for a variety of analytical
and quality control purposes. While the spiking of multiple
2. Referenced Documents
sample test portions is discussed, the method of standard
2.1 ASTM Standards:
additions is not covered.
D1129 Terminology Relating to Water
1.3 This guide is intended for use in conjunction with the
D1193 Specification for Reagent Water
individual analytical test method that provides procedures for
D3694 Practices for Preparation of Sample Containers and
analysis of the analyte or component of interest. The test
for Preservation of Organic Constituents
method is used to determine an analyte or component’s
D3856 Guide for Good Laboratory Practices in Laborato-
background level and, again after spiking, its now elevated
ries Engaged in Sampling and Analysis of Water
level. Each test method typically provides procedures not only
D4375 Practice for Basic Statistics in Committee D19 on
for samples, but also for calibration standards or analytical
Water
control solutions, or both. These procedures include prepara-
E200 Practice for Preparation, Standardization, and Stor-
tion, handling, storage, preservation, and analysis techniques.
age of Standard and Reagent Solutions for Chemical
These procedures are applicable by extension, using the
Analysis
analyst’s judgement on a case-by-case basis, to spiking solu-
tions, and are not reiterated in this guide. See also Practice
3. Terminology
E200 for preparation and storage information.
3.1 Definitions—For definitions of terms used in this guide,
1.4 Theseproceduresapplyonlytoanalytesthataresoluble
refer to Terminology D1129.
in water at the concentration of the spike plus any background
3.2 Definitions of Terms Specific to This Standard:
material, or to analytes soluble in a solvent that is itself
3.2.1 matrix spike, n—the quantity (mass) of a component
(analyte) of interest which is added to a sample (matrix) in
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. Annual Book of ASTM Standards, Vol 11.01.
Current edition approved Sept. 10, 1995. Published November 1995. Annual Book of ASTM Standards, Vol 11.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5788–95 (2001)
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
NOTE 1—Anyfieldspikedsample,ifknowntothelaboratory,shouldbe
several trials under specific analytical conditions represent the
labeledasafieldspikeinthefinalresultsreport.Also,wheneverpossible,
measurement efficiency with which the analyte may be deter-
field spiking of volatile compounds should be avoided.
mined under these conditions.
5.5 It is often tacitly assumed that the analyte component is
3.2.3 spiking solution—the solution in which one or more
recovered from the sample to approximately the same extent
spikes are dissolved (along with any necessary preservatives).
that a spike of the same analyte is recovered from a spiked
This solution acts as a carrier to provide ease of measurement
sample. One reason that this assumption may be incorrect is
and more rapid and thorough mixing of the spike into the
thatthespikemaynotbeboundupinthesample(forexample,
sample, as compared to adding the spike as a pure compound.
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
background level of the analyte. For this reason, as well as the
known amount of an organic analyte to an aqueous sample.
fact that bias corrections can add variability, it is not good
Instructions are given to help prevent loss of volatile analytes
practicetocorrectanalyticaldatausingspikerecoveries.Spike
in the sample headspace and to provide a homogeneous
recovery information should, however, be reported along with
solutionforsubsequentanalysis.Appropriateconcentrationsof
the related sample analysis results.
thespikerelativetotheoriginalconcentrationinthesampleare
5.6 This guide is also applicable to the preparation and use
discussed. Applications of the technique and aids in the
interpretation of results obtained are described. ofspikesforquantificationbythemethodofstandardadditions
and to the addition of surrogates and internal standards.
5. Significance and Use
5.1 Matrix spiking of samples is commonly used to deter-
6. Apparatus
mine the bias under specific analytical conditions, or the
6.1 StirringApparatus—Borosilicateglassbeads,4to6mm
applicability of a test method to a particular sample matrix, by
in diameter, or small TFE-coated magnetic stirring bars. A
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.
may be considered a measure of the stability of the analytes in
6.4 Syringes—Borosilicateglasssyringeswithdemountable
the matrix. Laboratory spiking tests the laboratory process
stainless steel needles may be used to measure volumes of
only.Spikingofsampleextracts,concentrates,ordilutionswill
samples(spikedorunspiked)tobeinjectedintopurge-and-trap
be reflective of only that portion of the process subsequent to
sample introduction systems.
the addition of the spike.
6.5 Volumetric Transfer Pipets—Class A, used to deliver
5.4 Special precautions shall be observed when nonlabora-
knownvolumesofsampleandtoaddlargervolumesofspiking
tory personnel perform spiking in the field. It is recommended
solutions.
thatallspikepreparationworkbeperformedinalaboratoryby
experienced analysts so that the field operation consists solely 6.6 Volumetric Flasks—Class A volumetric flasks may be
of adding a prepared spiking solution to the sample matrix. used to measure known volumes of sample.
D 5788–95 (2001)
6.7 Balance—An analytical (0.1-mg), semimicro (0.01- of a diluted spiking solution falls within the control limits for
mg), or micro (0.001-mg) balance. 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
spiking solution, and are diluted volumetrically to produce the
7.1 Purity of Reagents—At a minimum, reagent grade
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 that of the routine method calibration standards.
forthesespikingprocedures,areincludedinthisclassification.
7.2 Purity of Water—Unlessotherwiseindicated,references
9.2.1 Analyzeoneportionofthesamplefortheanalyte(s)of
to water shall be understood to mean reagent water as defined
interest. Duplicate analyses are recommended to determine the
by the individual test method to be used to analyze a sample
overallprecisionofthesamplesplittingandanalysisprocess.If
afterspiking.Ifmorethanonetestmethodistobeutilized,the
this is not possible, estimate the concentrations of analytes of
minimum criteria of each test method must be met. If test
interest, based upon knowledge of the sample source.
method reagent water specifications are not available, refer-
9.2.2 Use the result of this analysis or estimation to deter-
ences to water shall be
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