A comprehensive two-dimensional HPLC system for the separation of polycyclic aromatic hydrocarbons was developed using a pentabromobenzyl column as the first dimension and two short monolithic C₁₈ columns as the second dimension. The primary column and two secondary columns were coupled by a 10-port 2-position valve. The effluent from the first dimension was repetitively injected into the second dimension every 12 s. Due to its resolution, this technique is a powerful tool for the separation of polycyclic aromatic hydrocarbons in a complex matrix such as environmental samples.