scope:

This European Standard specifies methods for the extraction and clean-up of food samples of plant origin for quantitative determination of pesticide residues.

Different solvents can be used for this purpose. These pesticide residues are generally associated with other co-extracted compounds which would interfere in the analysis. To purify the crude extracts to be analysed, several techniques can be used.

This European Standard contains the following extraction and clean-up methods that have been subjected to interlaboratory studies and/or are adopted throughout Europe:

- method M: Extraction with acetone and liquid-liquid partition with dichloromethane/light petroleum, if necessary clean-up on Florisil® ¹⁾ [1], [2], [3];

- method N: Extraction with acetone, liquid-liquid partition with dichloromethane or cyclohexane/ethyl acetate and clean-up with gel permeation and silica gel chromatography [4], [5];

- method P: Extraction with ethyl acetate, and if necessary, clean-up by gel permeation chromatography [6].

This European Standard specifies the details of methods M, N and P for the extraction and the clean-up of food samples of plant origin. Several solvents at different volumes are used for extraction. Techniques of clean-up are listed such as liquid-liquid partition, liquid chromatography on various adsorbents and gel permeation chromatography.

A table providing the couples (matrix/pesticide) which have been submitted to collaborative studies and a list of indicative applicability of the method to different pesticides are given for each method, wherever possible.

1) Florisil®,is an example of a suitable product available commercially from U.S. Silica company. This information is given for convenience of users of this standard and does not constitute an endorsement by CEN of this product.