Demonstrating extraction efficiency of residue analysis methods

ACS 2023 -- Analytical methods used to support the registration of products have to be effective, robust and reliable, meeting a range of specific requirements, as demonstrated during the validation process. As these methods are normally developed following metabolism studies, information relating to the extraction technique is often used to develop the subsequent residue method, which ensures that the analyte tested is fully extracted from the sample matrix. This is particularly important when testing samples that may contain aged residues, such as samples originating from crop residue trials typically used to generate risk assessment data. As a result, assurances as to the efficiency of extraction are therefore of increasing importance, highlighted with the move toward more generic multi-residue approaches for residue methods. There is concern that this type of approach to residue analysis may not be effective in fully extracting aged/incurred residues from crop samples. This results in a requirement to demonstrate the extraction efficiency of the various residue methods in order to address this.