The present work was done to develop a novel nanocomposite using bone char coated with nano-gold for capture of elemental mercury (Hg-0) from air. The morphologies, structures, and chemical constitute of the prepared nanocomposite were evaluated by UV-VIS-NIR, dynamic light-scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infra-red (FTIR) spectroscopy, and energy dispersive X-ray spectroscopy (EDS). The capture performance of nanocomposite was evaluated in a needle trap for mercury vapor. An on-line setup based on cold vapor atomic absorption spectrometry (CVAAS) was designed for Hg-0 determination. Dynamic capacity of nanocomposite for Hg-0 was shown high efficient operating capacity of 586.7 mu g/g. As temperature increases, the dynamic adsorption capacity of the nanocomposite was decreased, which are characteristics of physicosorption processes. It was found that the surface modification of bone char with nano-gold has various advantages such as high operating dynamic adsorption capacity and low cost preparation. It was also demonstrated that the developed nanocomposite is suitable for on-line monitoring of Hg-0. It could be applied for the laboratory and field studies. (C) 2014 Elsevier B.V. All rights reserved.