Application of counter‐current chromatography as a new pretreatment method for the determination of polycyclic aromatic hydrocarbons in environmental water

Abstract

Counter-current chromatography (CCC) was investigated as a new sample pretreatment method for the determination of trace polycyclic aromatic hydrocarbons (PAHs) in water environmental samples. The experiment was performed with a non-aqueous binary two-phase solvent system composed of n-heptane and acetonitrile. The CCC column was first filled with the upper stationary phase, and then a large volume of water sample was pumped into the column while the CCC column was rotated at 1600 rpm. Finally, the trace amounts of PAHs extracted and enriched in the stationary phase were eluted out by the lower mobile phase and determined by gas chromatography-flame ionization detector (GC-FID) or gas chromatography-mass spectrometry (GC-MS). The enrichment and cleanup of PAHs can be fulfilled online by this method with high recoveries (84.1-103.2%) and good reproducibility (RSDs: 4.9-12.2%) for 16 EPA PAHs under the optimized CCC pretreatment conditions. This method has been successfully applied to determine PAHs in lake water where 8 PAHs were detected in the concentration of 40.9-89.9 ng/L. The present method is extremely suitable for the preparation of large volume of environmental water sample for the determination of trace amounts of organic pollutants including PAHs as studied in this paper.