Polycyclic aromatic hydrocarbons are components of different odor molecules and they often behave as environmental toxicants. Detection of such hydrocarbons is thus important for both sensing and environmental management perspectives. A simple design for liquid state single wall carbon nanotubes (SWNTs) based nano-capacitor is proposed in this paper. This design excludes the long fabrication process (e.g. integration with field effect transistors, chemo resistors, gravimetric or optical sensors) but includes a simple cyclic voltammetry principle. The specific interaction between the respective hydrocarbons and SWNTs enables detection of hydrocarbons at a significant level of sensitivity (ppm). (C) 2013 Elsevier B.V. All rights reserved.