Gold electrode quartz crystal microbalances (QCMs) were used as transducing platform to detect and sense elemental mercury (Hg) in gas phase. The enhanced sensitivity, resulting form the electro-deposition of gold nano-structures on the surface is shown to increase the response magnitude (RM) of the sensors in the presence of ammonia and humidity interference. The concentration of NH3 and H2O was varied in the range 590 to 1770mg/m3 and 4.2 to 10.4mg/m3, respectively. A constant gas flow of 200sccm, balanced in nitrogen was used as the carrier gas. The RM for Hg was enhanced by creating nanostructures on the sensorpsilas gold electrodes via electro-deposition of gold in a lead acetate electrolyte. The results presented are a critical step in the development of a cheap regenerable and reliable sensor for measuring Hg in the presence of interferents gases commonly found in industrial applications.