Analysis data for the Determination of Moisture by Karl
Fischer
and by Evaporation (Oven loss) in Barley
-4.100188097
Evaporation
Karl Fischer
-3
-2
-1
0
1
2
3
11
5
10
3
7
1
2
8
6
4
9
9
1
7
5
3
6
10
11
8
2
4
Lab id number
ZScore
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Determination of TruenessUsing injected samplesInjection of a
known quantity of a substance in a real sample determination of the
recovery
Cfrt: concentration determined in fortified sampleCunf:
concentration determined in unfortified sampleCadd: concentration
of fortification
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Interpretation of BiasInterlaboratory meanLaboratory biasMethod
biasTotal biasTrue valueMeasured value(laboratory mean)
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
PrecisionThe closeness of agreement between independent test
results obtained under stipulated conditions.
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
PrecisionPrecision under repeatability conditions:Same method on
identical test items, in the same laboratory,by the same operator,
using the same equipment, within short time intervalsPrecision
under reproducibility conditionsSame method on identical test
items, in different laboratories, with different operators, using
different equipment.
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Intermediate PrecisionRepeatability conditions and
Reproducibility Conditions are extreme casesIntermediate cases are
most frequentSame laboratory - different operatorsSame laboratory -
different equipment etc
ISO 5725
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Evaluation of Precision10 samples for each conc.under r,R,
within lab RStandard Deviation
R=3s (99%confidence, 15 days)Determination in pairs under r,R,
within lab RStd. Dev. between two single determinations
a-b, the difference between the values, d, the number of
pairs
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
PrecisionRepeatability limitReproducibility limit
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Sensitivity
The change in the response of a measuring instrument divided by
the corresponding change in the stimulus
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Ruggedness and RobustnessIntra-laboratory study to check changes
due to environmental and/or operating conditions Usually it is part
of method developmentDeliberate changes in TemperatureReagents (
e.g. different batches)Extraction timeComposition in the
sampleetc
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
The Tools of ValidationBlanksReagent blanksSample
blanksSamples/test materialsFortified materials/solutionsSpiked
materialsIncurred materials
Independently characterized materialsMeasurement
standardsReference materialsCertified Reference
materialsStatisticsReplication
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Using Validated MethodsMake yourself familiar with the new
methodMake necessary preparations before you start workingAnalyze
only an optimum number of samplesRe-validate as appropriate
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Validation and Quality ControlInternal QCQC samples and the use
of control chartsWarning and action limitsQC samples to be within
limitsRealistic limits on the control chartVarious types of blanks
to correct the responseReplicate analysis to check changes in
precisionBlind analysis to check precisionStandards and chemical
calibrants to check the stability of the response
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Validation and Quality ControlExternal QCProficiency
testingMonitor of laboratory performanceHighlight
reproducibilityMonitor of traceabilityRecognized by accreditation
bodiesPT results as means of checking QA
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Documentation of Validated MethodsDocumentation of the
validation procedureClear and unambiguous implementationConsistency
during applicationLarge uncertainty contribution if inadequately
documented methodsInformation to be easily understood by everyone
using the method
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
The Method Documentation ProtocolUpdate & Review
SummaryTitleScopeWarning & Safety
precautionsDefinitionsPrincipleReagents & MaterialsApparatus
and equipmentSampling and samples
CalibrationQuality ControlProcedureCalculationReporting
procedures including expression of resultsNormative
referencesAppendix on method validationAppendix on measurement
uncertainty
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Interpretation of Validation DataValidation data to give answers
and solutions to customers problemsAnalysts access to the
validation dataThe analytical chemist as a technical
advisorInterpretation of the measurement uncertainty of
resultsLegal and forensic contexts When reporting the resultsEither
to correct for bias or to acknowledge biasNot detected statement to
be accompanied by the detection limitExpression of
uncertainties
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
SummaryThe analytical method as a measurement toolValidation and
revalidationCorrect use of validation dataValidation data as a
measure of the method performance
Hadjicostas E.: Validation of Analytical Methods Springer-Verlag
Berlin Heidelberg 2003
Where to Get More Informationhttp://www.eurachem.ul.ptThe
Fitness for purpose of analytical methods, Eurachem GuideISO 5725
1986 (E), Precision of Test Methods - Determination of
repeatability and reproducibility for a standard test method by
interlaboratory tests.
