Experimental losses and optimum conditions for phenanthrene extraction

Polycyclic aromatic hydrocarbons (PAHs) are a class of pollutants that are widespread in the environment. Their hydrophobic properties make accurate analyses very difficult. In addition, the experimental losses during extraction of PAHs are inevitable and of great concern. In this study, dichloromethane (DCM), chloroform (CF), and carbon disulfide (CDS) were used as solvents to extract phenanthrene (PHN), a typical PAH, at various temperature and pressure reduction conditions. The extraction was improved using a multiple microtube extraction methodology. The results indicate that the CDS had the best performance followed by CF and DCM at 25°C and standard pressure. This was ascribed to the intensity of the molecular interactions between the solvent, the water, and the PHN due to their different molecular structures leading to different stereo and hydrogen bonding effects. The optimum conditions for extraction of PHN by CDS were determined by correlating the experimental results. The regression shows that the experimental loss rate is linearly proportional to the pressure reduction and exponentially related to the temperature. The correlation can be used to improve extraction efficiencies.