German official method validation

German official methods group validated two ELISA kits for hazelnut in plain chocolate LEGB (2006)... 

In summary, official German analytical methods for pesticide residues are always validated in several laboratories. These inter-laboratory studies avoid the acceptance of methods which cannot readily be reproduced in further laboratories and they do improve the ruggedness of analytical procedures applied. The recently introduced calibration with standards in matrix improves the trueness of the reported recovery data. Other aspects of validation (sample processing, analyte stability, extraction efficiency) are not considered. 

To reduce the effort, another validation procedure is used for extension of the German multi-residue method to a new analyte. Actually, more than 200 pesticides can be analyzed officially with this method, which is the up-to-date version of the better known method DFG SI9. A typical validation is performed by at least three laboratories, which conduct fortification experiments at the same three levels with at least four representative matrices. These representative matrices are commodities with high water content (e.g., tomato), fruits with high acid content (e.g., lemon), dry crops (e.g., cereals) and commodities with high fat content (e.g., avocado). 

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