Quartz crystal microbalance sensor coated with polyaniline emeraldine base for determination of chlorinated aliphatic hydrocarbons

A quartz crystal microbalance (QCM) sensor coated with a thin film of polyaniline emeraldine base (EB) was used as a sensitive method for the determination of a number of aliphatic chlorinated hydrocarbons such as carbon tetrachloride, chloroform, dichloromethane, 1,2-dichloroethane vapours. The detection was based on the absorption of the vapours of these organic compounds into the EB film. The frequency shifts due to the absorption of the chlorinated hydrocarbons were measured and calibration curves were plotted. The detection of these vapours can be obtained in part per million (ppm). The work includes also the use of a polyaniline emeraldine salt (ES) film instead of the EB film. It is concluded that the EB film has higher sensitivity towards the organic vapours than the ES film, which can be attributed to the presence of unprotonated amine and imine groups along the polyaniline (PANI) chains in the EB form.