Separation of Polyaromatic Hydrocarbons Using 2-Dimensional Thin-Layer Chromatography. An Environmental Chemistry Experiment

An experiment for an undergraduate environmental chemistry course is described. Students are given a soil sample from which they extract two (previously added) polyaromatic hydrocarbons (PAHs) using a Soxhlet apparatus. They determine the identity of the unknown PAHs by comparing the 2-dimensional thin-layer chromatograms of the soil sample extract and a standard solution, both of which they must run themselves. Definitive identification is given by R f values and fluorescence colors (under 254-nm UV light). The experiment is suitable to be performed by large classes (ca. 30 students) and is, on average, completed in three hours.