Guidelines For Performance Criteria And Validation -PDF Free Download

Guidelines for performance criteria and validation

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Guidelines for performance criteria and validation procedures of analytical methods used in controls of food contact materials Stefanka Bratinova, Barbara Raffael, Catherine Simoneau . 2 The mission of the IHCP is to provide scientific support to the development and implementation of EU policies related to health and consumer protection. The IHCP carries out research to improve the ...



The mission of the IHCP is to provide scientific support to the development and implementation of EU
policies related to health and consumer protection
The IHCP carries out research to improve the understanding of potential health risks posed by
chemical physical and biological agents from various sources to which consumers are exposed
European Commission
Joint Research Centre
Institute for Health and Consumer Protection
Contact information
Address DG JRC IHCP TP 260 I 21020 Ispra
E mail Catherine simoneau jrc ec europa eu
Tel 39 0332 785889
Fax 39 0332 785707
http ihcp jrc ec europa eu
http www jrc ec europa eu
Legal Notice
Neither the European Commission nor any person acting on behalf of the Commission is responsible for
the use which might be made of this publication
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to your questions about the European Union
Freephone number
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It can be accessed through the Europa server http europa eu
EUR 24105 EN
ISBN 978 92 79 14483 7
ISSN 1018 5593
DOI 10 2788 49046
Luxembourg Office for Official Publications of the European Communities
European Communities 2009
Reproduction is authorised provided the source is acknowledged
Printed in Italy
Executive Summary
Test methods for materials and articles in contact with foodstuffs are required to
determine the concentration of residues of monomers in the materials themselves or to
determine the concentration of individual or groups of substances in food or food
simulants which have migrated from the food contact materials
The Community Reference Laboratory and National Reference Laboratories for food
contact materials FCM prepared the present Guidelines to illustrate the required
performance criteria for the analytical methods applied in the laboratories for FCM and
provide procedures for method validation in order to estimate their performance
characteristics The scope of these guidelines is to provide rules for the performance of
the analytical methods to be used in the verification of compliance with the migration
limits defined in Directive 2002 72 EC as amended and in accordance with Directive
82 711 EEC as amended and others defined in the European legislation in order to
ensure the quality and comparability of the analytical results
The document presents 4 approaches according to the different purpose of
performance assessment
These guidelines are intended as a dynamic document and they will evolve and
expand into further editions This is the first edition These guidelines have been
endorsed by the European Union official Network of National Reference Laboratories
and approved by the EU Commission competent service DG SANCO
This work also highlights an important deliverable for the Network of NRLs In
particular the members of the task force Method Performance that have dedicated
time and effort to provide input into the development of these guidelines They are
gratefully acknowledged here for their contribution NRL BE Fabien Bolle Tina n Goy
NRL DE Oliver Kappenstein NRL DK Jens Petersen NRL ES Juana Bustos
NRL FR1 Patrick Sauvegrain NRL EL Timokleia Togkalidou NRL IT Maria
Rosaria Milana NRL NL Durk Schakel Dita Kalsbeek van Wijk NRL PL Kazimiera
Cwiek Ludwicka NRL SI Viviana Golja NRL UK Emma Bradley Special thanks
are extended to Emma Bradley for her contribution to the editing of the document
Acknowledgement
This work was performed thanks to the CRL mandate
SANCO 2007 FOODSAFETY 0043 Contact Materials
SANCO 2008 FOODSAFETY 0047 Contact Materials
SANCO 2008 FOODSAFETY 055 Contact Materials
Table of Contents
1 INTRODUCTION 7
2 SCOPE OF THIS DOCUMENT 8
3 GLOSSARY DEFINITIONS 8
4 METHOD VALIDATION PLAN 9
4 1 CHOICE OF VALIDATION SCHEME 9
4 1 1 Full single laboratory validation protocol applicable to the field of food contact
materials and articles 10
4 1 2 Standard level of single laboratory validation applicable to the field of food contact
materials and articles 10
4 1 3 Basic level of single laboratory validation applicable to the field of food contact
material and articles 10
4 1 4 Method verification 11
5 FULL SINGLE LABORATORY METHOD VALIDATION PROCEDURE 15
5 1 PERFORMANCE CHARACTERISTICS OF THE MIGRATION PART 16
5 2 PERFORMANCE CHARACTERISTICS OF THE DETERMINATION ANALYTICAL PART 18
5 2 1 Selectivity specificity 19
5 2 2 Ruggedness 19
5 2 3 Calibration range assessment of the calibration function 21
5 2 4 Working concentration range 32
5 2 5 Limit of detection LOD method detection limit MDL 32
5 2 6 Limit of quantification 35
5 2 7 Accuracy 35
5 2 8 Uncertainty 49
5 3 REPORTING OF RESULTS 55
5 4 INTERPRETATION OF RESULTS 55
5 5 VALIDATION VERIFICATION DOCUMENTATION 55
5 6 MONITORING OF THE VALIDATED METHOD 56
6 STANDARD LEVEL VALIDATION SCHEME FOR FCM METHODS 57
6 1 SELECTIVITY SPECIFICITY 57
6 2 RUGGEDNESS 57
6 3 CALIBRATION RANGE ASSESSMENT OF CALIBRATION FUNCTION 57
6 3 1 Calibration range 57
6 3 2 Basic of calibration and quantification 57
6 3 3 Assessment of the linearity model 58
6 4 WORKING CONCENTRATION RANGE 58
6 5 LOD 58
6 6 LOQ 58
6 7 PRECISION 59
6 8 TRUENESS 60
6 9 UNCERTAINTY 60
7 BASIC LEVEL VALIDATION SCHEME FOR FCM METHODS 61
7 1 SELECTIVITY SPECIFICITY 61
7 2 RUGGEDNESS 61
7 3 ASSESSMENT OF CALIBRATION FUNCTION 61
7 3 1 Calibration range 61
7 3 2 Basic of calibration and quantification 61
7 3 3 Assessment of the linearity model 61
7 4 WORKING CONCENTRATION RANGE 62
7 5 LOD 62
7 6 LOQ 62
7 7 PRECISION 62
7 8 TRUENESS 63
7 9 UNCERTAINTY 64
8 REFERENCES 64
1 INTRODUCTION
The European Framework Regulation EC No 1935 2004 29 is the basic
Community legislation that covers all food contact materials and articles It
empowers the European Commission to set requirements for specific materials
Specific requirements for such materials can include limits on the overall migration
and on the specific migration of certain constituents or groups of constituents into
foodstuffs These limits have been defined for some substances in plastic materials
and articles
Test methods for materials and articles in contact with foodstuffs are required to
determine the concentration of residues of monomers in the materials themselves or
to determine the concentration of individual or groups of substances in food food
simulants which have migrated from the food contact materials or to determine
overall migration from food contact materials
The determination of migration from materials and articles intended to come into
contact with foodstuffs is quite unlike any other measurement tasks in ensuring food
safety and quality Reliable measurements depend upon more than simply having
validated analytical methods for measuring chemical concentrations in foods The
Directives allows as an alternative to the analysis of the foodstuff itself migration
testing to be carried out with food simulants applied under conditions which simulate
actual use of the material or article with food This introduces additional potential
sources of variability in the final migration value
It is necessary to ensure the quality and comparability of the analytical results
generated by laboratories for enforcement purposes for compliance purposes and
for the creation of data for risk assessment purposes This should be achieved by
using quality assurance systems and specifically by applying methods that have
been validated according to common procedures and that meet defined performance
criteria and by ensuring traceability to common standards or standards that are
commonly agreed upon
Commission Regulation EC No 882 2004 30 on official controls performed to
ensure the verification of compliance with feed and food law animal health and
animal welfare rules which also incorporates food contact materials requires official
control laboratories to be accredited according to EN ISO IEC 17025 21 Moreover
approved laboratories must prove their competence by regular and successful
participation in adequate proficiency testing schemes recognised or organised by the
national or Community reference laboratories
A network of Community Reference Laboratory and National Reference Laboratories
for food contact materials FCM operates under Commission Regulation EC No
882 2004 30 to enhance coordination
In the field of materials and articles in contact with food numerous chemicals are
used in the manufacturing processes and it is not possible to prepare standard test
methods for all Therefore the concept of routine methods and reference methods
should be superseded by a criteria approach in which performance criteria and
procedures for the validation of screening and confirmatory methods are defined
It is necessary to determine common criteria for the interpretation of test results of
official control laboratories in order to ensure a harmonised implementation of
Commission Regulation EC No 882 2004 30
2 SCOPE OF THIS DOCUMENT
The scope of these guidelines is to provide rules for the performance of the
analytical methods to be used in the verification of compliance with the migration
limits defined in Directive 2002 72 EC 22 as amended and in accordance with
Directive 82 711 EEC 23 as amended and 85 572 EEC 24 as amended and the
further provisions set out in Annex 1 of Commission Directive 2002 72 EC 22
The verification of compliance with the migration limits is made using methods that
a are documented in test instructions preferably according to ISO 78 2 20
b comply with the performance criteria defined in these guidelines
c have been validated according to the procedures described in these
guidelines
The quality of the results of the analysis of samples for verification of the compliance
with the migration limits should be ensured according to Chapter 5 9 of ISO 17025
3 GLOSSARY DEFINITIONS
Abbreviations Explanation
The closeness of agreement between a test result and the accepted reference value It is
determined by determining trueness and precision
The substance and any derivatives emerging during its analysis that has to be detected
identified and or quantified
Bias The difference between the expectation of the test result and an accepted reference value
A device for measurements that represents the quantity of substance of interest in a way that ties
Calibration standard
its value to a reference base
Certified reference A material that has had a specified analyte content or for food contact materials a migration
material CRM value assigned to it
Analysing the same sample by the same method to determine the performance characteristics of
Collaborative study
the method The study covers random measurement error and laboratory bias
Compositional limit QM The maximum permitted amount of the named substance in the material or article
Methods that provide full or complementary information enabling the substance to be
Confirmatory method
unequivocally identified and if necessary quantified at the level of interest
Food Simulant A medium intended to simulate mimic or model the essential characteristics of a foodstuff
Fortified sample material A sample enriched with a known amount of the analyte to be detected
Organisation performance and evaluation of tests on the same sample by two or more
Interlaboratory study
laboratories in accordance with predetermined conditions to determine testing performance
comparison
According to the purpose the study can be classified as collaborative study or proficiency study
A substance not contained in the sample with physical chemical properties as similar as possible
Internal standard IS to those of the analyte that has to be identified and which is added to each sample as well as to
each calibration standard
The concentration of a substance or analyte in a sample that is significant to determine its
Level of interest
compliance with legislation
The mass of material transferred to the food simulant or test media as determined by the relevant
Overall migration
test method
Functional quality that can be attributed to an analytical method This may be for instance
Performance
specificity accuracy trueness precision repeatability reproducibility recovery detection
characteristic
capability and ruggedness
Requirements for a performance characteristic according to which it can be judged that the
Performance criteria
analytical method is fit for the purpose and generates reliable results
The closeness of agreement between independent test results obtained under stipulated
predetermined conditions The measure of precision usually is expressed in terms of
imprecision and computed as standard deviation of the test result Less precision is determined
by a larger standard deviation
Analysing the same sample allowing laboratories to choose their own methods provided these
Proficiency study methods are used under routine conditions The study has to be performed according to ISO
guide 43 1 31 and 43 2 32 and can be used to assess the reproducibility of methods
Range working or
Means a set of values for which a measure is intended to lay within specified uncertainty limits
The percentage of the true concentration of a substance recovered during the analytical
procedure It is determined during validation if no certified reference material is available
A material of which one or several properties have been confirmed by a validated method so that
Reference material
it can be used to calibrate an apparatus or to verify a method of measurement
Conditions where independent test results are obtained with the same method on identical test
Repeatability conditions items in the same laboratory by the same operator using the same equipment and short interval
Precision under repeatability conditions r the value below which the absolute difference
Repeatability between 2 single test results obtained under repeatability conditions may be expected to lie
within a specific probability typically 95 and hence r 2 8 x sr
Conditions where test results are obtained with the same method on identical test items in
Reproducibility conditions
different laboratories with different operators using different equipment
Precision under reproducibility conditions R the value below which the absolute difference
Reproducibility between 2 single test results obtained under reproducibility conditions may be expected to lie
within a specific probability typically 95 and hence R 2 8 x sR
Residual content The mass of the substance present in the final material or article
The susceptibility of an analytical method to changes in experimental conditions which can be
expressed as a list of the sample materials analytes storage conditions environmental and or
sample preparation conditions under which the method can be applied as presented or with
Ruggedness
specified minor modifications For all experimental conditions which could in practice be subject
to fluctuation e g stability of reagents composition of the sample pH temperature any
variations which could affect the analytical result should be indicated
Sample blank The complete analytical procedure applied to a test portion taken from a sample from which the
determination analyte is absent
Methods that are used to detect the presence of a substance or class of substances at the level
of interest These methods have the capability for a high sample throughput and are used to sift
Screening method
large numbers of samples for potential non compliant results They are specifically designed to
avoid false compliant results
Single laboratory study An analytical study involving a single laboratory using one method to analyse the same or
in house validation different test materials under different conditions over justified long time intervals
The maximum permitted level of a group of named substances migrating from the final material or
SML T article into food or food simulants expressed as total of chemical moiety or substance s
Specific Migration The mass of the substance transferred to the food simulant as determined in the test method
Specific Migration Limit The maximum permitted level of a named substance migrating from the final material or article
SML into food or food simulants
Ability of a method to distinguish between the analyte being measured and other substances
Specificity This characteristic is predominantly a function of the measuring technique described but can
vary according to class of compound or matrix
A procedure in which the test sample is divided in two or more test portions One portion is
analysed as such and known amounts of the standard analyte are added to the other test
portions before analysis The amount of the standard analyte added has to be between two and
Standard addition
five times the estimated amount of the analyte in the sample This procedure is designed to
determine the content of an analyte in a sample taking account of the recovery of the analytical
The closeness of agreement between the average value obtained from a large series of test
results and an accepted reference value Trueness is usually expressed as bias
The confirmation by examination and the provision of effective evidence that the particular
Validation
requirements of a specific intended use are fulfilled
Precision obtained in the same laboratory under stipulated predetermined conditions
Within laboratory
concerning e g method test materials operators and environment over justified long time
reproducibility
4 METHOD VALIDATION PLAN
4 1 Choice of validation scheme
The detailed design and the correct execution of method validation studies should
as far as possible provide a realistic assessment of the number and range of effects
operating during normal use of the method as well as covering the working
concentration range s and sample types that fall within the scope of the method
The applicable working concentration range is an important part of the validation or
verification of the analytical method It will often save both time and effort to choose
the area of application on the basis of laboratory or Regulatory needs instead of
validating the whole range of possibilities
It is also important that the validation and verification report describes which sample
matrices have been used In fact the performance of some methods may be also
dependent on the matrix In such cases it is very important to ensure that the entire
stated area of application is included in the validation
Validation or verification of an already validated method must always be performed
before it is used in the laboratory for official control purposes This work must be
repeated partly or fully if the result of the first validation makes it necessary to modify
the method
In the following paragraphs four different approaches are presented
4 1 1 Full single laboratory validation protocol applicable to the field
of food contact materials and articles
Full validation should be performed for newly developed methods or methods
published in scientific literature but without important performance characteristics
that are to be used for standardisation purposes or in public control
Full validation of a method means thorough examination and determination of the
performance characteristics of the method Validation should demonstrate that the
analytical method complies with the established criteria applicable for the relevant
performance characteristics
A single laboratory validation cannot be considered a real full validation and some of
the parameters assessed have a consistent value only for the laboratory that
performed the validation more details will be provided in the specific chapters
4 1 2 Standard level of single laboratory validation applicable to the
field of food contact materials and articles
This scheme represents the conditions specifically developed and agreed by the
official control laboratories for FCM which should be applied as a working standard
for use in the field of FCM This validation scheme represents the minimum
requirements to establish non compliance of a material or article intended for food
Experienced laboratories who have already implemented more sophisticated
procedures compliant with consolidated standards of validation can continue to use
them provided they respect at least the minimum requirements set by the agreed
level described in these guidelines
4 1 3 Basic level of single laboratory validation applicable to the field
of food contact material and articles
This scheme represents the base level that must be met by all laboratories This
level does not fulfil all of the legal and official requirements but it is considered as
the starting point from which a harmonised level of control and results in all
European countries can be achieved From this starting point the laboratories will
have to update and improve their procedures and achieve the level foreseen for the
Standard level validation by January 2011
This Basic level validation may also be used for emergency or occasional cases
and or for a reduced number of samples In such cases this approach may be used
beyond 2011
Experienced laboratories who have already implemented more sophisticated
procedures compliant with consolidated standards of validation can continue to use
them provided they respect at least the minimum requirements set by the agreed
level described in these guidelines
4 1 4 Method verification
Method verification is the examination of a laboratory s ability to perform the analysis
in accordance with the method parameters established in the validation of the
method This scheme should be followed to prior to the use of an already validated
method by another laboratory or by the same laboratory but that has not used the
method for a defined period of time or when the method is used regularly but the
method performance has not been checked for a defined period of time
The extent of the verification performed locally in each laboratory depends on how
thoroughly the method has been validated a thorough validation simplifies the
internal verification It should be emphasised that some methods although issued by
standardisation bodies have not been validated through collaborative studies and
have to be thus validated and not only verified
Verification should be performed every year if the method is used regularly
Figure 1 4 show the respective flow charts for the four validation and verification
processes described above
FULL VALIDATION
Worked examples
Specificity
At least 3 blanks from
reproducibility
Robustness
8 repetitions in at least
duplicate of the method
6 calib curves from
reproducibility
range From calibration curve
LOD LOQ From blank or calib curve
6 repetitions 3 conc blank 2
Repeatability calibration curves in 1 day by 1
Reproducibility 6 repetitions 3 conc blank 2 cal
Accuracy curves repeated for other 2 days
by diff operators
Bias From CRM RM
Trueness collaborative study PT or
spiked samples
Recovery On 3 conc for the 3 days from
reproducibility
Based on validation
From reprod and bias
Uncertainty
Based on GUM approach From all uncertainty
Figure 1 Flow chart of a full validation scheme for FCM
FCM STANDARD SCHEME
Worked example
3 calib curve from
reproducibility
LOQ From precision lowest level
7 repetitions of LL level 1 calibration
Precision Repeatability curve in 1 day by 1 operator
Reproducibility
3 repetitions of 0 2 LL 1 LL and 2 LL
repeated for 3 different days by different
OR operators
Repeatability
Accuracy Reproducibility
ANOVA using a
combination of table 10
From CRM RM collaborative
study PT or spiked samples
On 3 replicates at 3 conc levels
the LL 0 2 LL and 2 LL from
u Rw ubias
Uncertainty uc From reproducibility and recovery
Figure 2 Flow chart of the effective standard working validation scheme for FCM
BASIC LEVEL SCHEME
Worked example
3 calib curve from
reproducibility
LOQ From precision lowest level
5 repetitions of LL 1 calibration
Precision Repeatability curve in 1 day by 1 operator
Reproducibility 3 repetitions of LL 1 cal curves
repeated for other 2 days by diff oper
OR Repeatability
Accuracy Reproducibility
ANOVA using a
combination of table 10
From CRM RM collaborative
study PT or spiked samples
On 3 replicates at the LL from
reproducibility
Uncertainty RSD From precision study
Figure 3 Flow chart for bottom level validation process
VERIFICATION
Worked example
6 sample repetitions 2 calibration
curves in 1 day by 1 operator
Precision Repeatability
From CRM RM collaborative
study PT or spiked samples
On 3 conc for the 3 days
From blank or calib curve
Uncertainty As calculated in the method to be
Figure 4 Flow chart for a verification process
5 FULL SINGLE LABORATORY METHOD
VALIDATION PROCEDURE
In the validation of test methods in the field of FCM the following cases could be
encountered
An overall migration test for the determination of the total quantity of all non
volatile substances that have migrated from the FCM test specimen to a food
A specific migration test for the determination of the substances in food
simulants that have migrated from a food contact material or article
The determination of the substance s in food that have migrated from a food
contact material or article
The determination of residues of monomers in food contact materials and
articles intended to come into contact with foodstuffs
In an overall migration test the total quantity of all of the substances that have
migrated from the test specimen of a food contact material or article to a food
simulant is determined gravimetrically using the procedures outlined in European
Commission Directive 2002 72 EC 22 as amended and the detailed methods in
the EN 1186 series of standards
In a specific migration test the quantity of an individual substance monomer
additive etc or group of substances is determined in a food simulant following the
exposure of a food contact specimen to the food simulant for the prescribed period of
time at the prescribed temperature using an appropriate analytical method
Both of these migration tests consist of two parts the exposure of the test specimen
to the food simulant or food for specific migration and the analytical determination
part The performance characteristics of both a specific migration test and an overall
migration test are a combination of factors from the migration part and the
determination part of the test The outcome of the exposure part and therefore the
test result is furthermore dependent on the material tested e g degree of
homogeneity and interaction with the food or food simulant and the test conditions
The performance characteristics for the determination of substances in food when
the material is already in contact with the food and the determination of residues of
monomers in food contact materials are just those of the determination part
analytical method
The methods described allow compliance with the following legislative limits LL to
be demonstrated
QM Maximum permitted quantity of the residual substance in the material or
QM T Maximum permitted quantity of the residual substance in the
material or article expressed as total of moiety or substance s indicated
QMA Maximum permitted quantity of the residual substance in the finished
material or article expressed as mg per 6 dm2 of the surface in contact with
foodstuffs


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