Application of matrix solid-phase dispersion in the determination of dibenzo[a,l]pyrene content of experimental animal diets used in a large-scale tumor study

A method utilizing matrix solid-phase dispersion (MSPD) was developed for i solation and determination of dibenzo[a,l]pyrene (DBP) in experimental rain bow-trout diets used in a large-scale carcinogenesis study. A 0.5 g sample of moist ration containing 0-225 ppm DBP (dry basis) was mixed with 2 g C-1 8 sorbent and benzo[a]pyrene internal standard was added to the mixture. Ex traction and clean-up were accomplished in a single step by extracting the sample mixture with hexane-benzene 4:1 from a cartridge containing 2 g Flor isil (R). DBP was quantified by HPLC on a C-8 bonded phase column with fluo rescence detection. Mean analytical recovery of DBP from control diet spike d at three concentration levels was 101 to 107% with relative standard devi ations of I to 7%. The limit of detection of DBP was equivalent to 0.014 pp m in the ration. Application of the method to verification of DBP levels in trout rations from the carcinogenesis study is described. Control ration ( 0 ppm DBP) was screened for possible DBP contamination and none was found. This is the first report on analysis of DBP in experimental animal diets. ( C) 2001 Elsevier Science BM All rights reserved.