EVIDENCE FOR THE ADSORPTION OF NITRATED POLYCYCLIC AROMATIC-HYDROCARBONS BY TREE BARK

It has been previously demonstrated that polycyclic aromatic hydrocarb ons (PAH) are adsorbed onto tree bark and that bark may in fact be use d as a passive sampler for these compounds. It is now demonstrated tha t by suitable modification of this methodology nitrated polycyclic aro matic hydrocarbons (nitro-PAH) may also be detected in bark. Bark samp les were taken from urban locations in Sheffield, South Yorkshire, UK. After soxhlet extraction using dichloromethane, the nitro-PAH fractio n was isolated by solid-phase extraction using amino and alumina cartr idges in series. Nitro-PAH were detected by gas chromatography with el ectron capture detection and gas chromatography-mass spectrometry in t he negative chemical ionisation mode. A comparison is made with nitro- PAH found in diesel particulate extracts. (C) 1997 Elsevier Science B. V.