A method for analysing polycyclic aromatic hydrocarbons (PAHS) in plant samples

A method was developed for the cleanup of maize samples prior to PAH analysis. The cleanup consists of two steps: (1) gel permeation chromatograpy on a porous styrene/divinylbenzene copolymer (Bio Beads SX8, Bio Rad Laboratories) and (2) further cleanup on silica gel. Quantification was performed with high resolution gas chromatography / high resolution mass spectrometry (HRGC/HRMS) using deuterated internal standards. The recoveries for a 12C-PAH standard mixture of 14 compounds (n=3) were approximately 100% exept for Perylene and Indeno(1,2,3-cd)pyrene. The analysis of three samples of maize leaves, each in parallel, gave highly reproducible results. In no case were interferences during the HRGC/HRMS measurements observed. The cleanup method is therefore regarded as very effective, reproducible, relatively inexpensive and sufficiently fast.