Analysis of priority pollutants in environmental samples by on-line supercritical fluid chromatography cleanup–cryo-trap–gas chromatography–mass spectrometry

Abstract

On-line coupling of a supercritical fluid chromatography cleanup system with gas chromatography–mass spectrometry (GC–MS) was performed using a custom-made cryo-trap cell. The cleanup system was based on a high-performance liquid chromatography (HPLC) column packed with about 100 mg of Florisil. This coupling considerably reduces the effect of high boiling compounds on the chromatographic efficiency in the determination of organic pollutants in environmental samples. Moreover, it enables multistep elution from the cleanup column by the addition of a suitable supercritical CO 2 modifier, which was performed automatically. The system was proved for the determination of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls in sediment reference material samples, and in spiked sea-water samples. In particular, a three-step elution of selected PAHs, which were the most retained, from the Florisil column was performed at 40°C and 25 MPa, at a supercritical CO 2 flow of 0.4 ml/min for a total elution time of 10 min. The recovery of all contaminants considered was always better than 75%, with a relative standard deviation of about 15%.