Dedicated to Professor Jacqiies Nasielski (ULB) ott the occasiott of Itis retireritetit ABSTRACT Analytical methodology has been developed for the isomer specific analysis of fieen 2,3,7,8-substituted polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans in decabromodiphenyloxide and tetrabromobisphenol-A. The procedures, developed by the Brominated Flame Retardant Industry Panel, Triangle Laboratories, Incorporated, and Battelle, have been shown to afford accurate and precise measurements of the analytes in these matrices. Analysis of multiple DBDPO and TBBPA samples, collected at random, show that none of the analytes are present in concentrations at or above specifled limits of quantitation.