# Commission Decision of 12 August 2002 implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results (notified under document number C(2002) 3044) (Text with EEA relevance) (2002/657/EC), Division 2.4.1: Common performance criteria and other requirements for confirmatory methods

Extent: E+W+S+N.I.

Reference or fortified material containing known amounts of analyte, at or near either the maximum permitted limit or the decision limit (non-compliant control sample) as well as compliant control materials and reagent blanks should preferably be carried through the entire procedure simultaneously with each batch of test samples analysed. The recommended order for injecting the extracts into the analytical instrument is as follows: reagent blank, compliant control sample, sample to be confirmed, compliant control sample and finally non-compliant control sample. Any variation from this shall be justified.
In general, most analytical techniques require complete digestion of the organic matrix to obtain solutions prior to determination of the analyte. This can be achieved by using microwave mineralisation procedures, which minimise the risk of loss and/or contamination of the analytes of interest. Decontaminated Teflon vessels of good quality shall be used. If other wet or dry digestion methods are resorted to, documented evidence shall be available to exclude potential loss or contamination phenomena. As an alternative to digestion, separation procedures (e.g. extraction) may under certain circumstances be chosen to separate analytes from matrix components and/or to concentrate analytes in order to introduce them into the analytical equipment.
As regards calibration, be it external or based on the standard addition method, care shall be taken not to exceed the working range established for the analysis. In the case of external calibration, it is mandatory that calibration standards are prepared in a solution that matches as closely as possible the composition of the sample solution. Background correction shall be also applied if required by specific analytical circumstances.

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Source: https://www.legislation.gov.uk/eudn/2002/657/annex/chapter/2.4/division/2.4.1 (the official version)
Page: https://openlegislation.uk/eu-decision-2002-657/annex/chapter-2.4/division-2.4.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.