July 2019 Flavanols ERP - Review Book

Review of method modifications for AOAC Method 2012.24 “ Flavanol and Procyanidin (by Degree of Polymerization 1-10) of Chocolate, Cocoa Liquors, Powder(s), and Cocoa Flavanol Extracts” By Darryl Sullivan The method authors submitted a request for method modifications including: • Modification of the analytical separation column and the gradient conditions used in the HPLC system • Replacement of the epicatechin standard with a cocoa extract calibrant that consists of DP1-7 species at known concentrations. These recommended changes were well documented and a revised manuscript was submitted. The rational for the change in HPLC column and the resulting changed in the gradient program were thoroughly explained. The substitution of the new calibration standard was well documented and I expect will actually improve the method. The single laboratory validation (SLV) that was submitted was well done and did a nice job of evaluating the method modifications. I only have one concern: the precision that was found in the SLV study shows the repeatability precision and intermediate precision having RSD’s of 1% and better. This is highly unusual for a complicated HPLC method and usually indicates that the analysts were highly trained and practiced in this procedure, before the completed the SLV. This is only something to take note of for now. I vote to approve these method modifications.

Darryl Sullivan Chief Science Officer Eurofins Scientific