Aliphatic amines vapours detection by quartz crystal microbalance sensor

Abstract

Polymerized castor oil based quartz crystal microbalance (QCM) sensors are fabricated for the detection of aliphatic amines vapours. The sensors are fabricated by solution dip-dry method followed by heating at 100°C under argon atmosphere to get cross linked film on QCM surface. A series of sensors with various weight percentages of benzoyl peroxide added to the solution are fabricated for the optimization of the sensitivities of the polymeric films. It is found that the sensor fabricated with a solution having 1.40% (w/v) of benzoyl peroxide has high sensitivity for vapours of organic compounds and are very effective for aliphatic amines vapours. The adsorption of the vapours to the surface of the QCM sensor is determined by the frequency shift of QCM. The frequency shift linearly increases with the gas vapour concentrations from 5 to 250ppm at room temperature. The sensitivity-values of methylamine, ethylamine, tert-butylamine, diethylamine, triethylamine and ammonia vapours are 0.917, 0.657, 0.655, 0.543, 0.407 and 0.397Hz/ppm respectively. The structure of the polymeric film is studied by FTIR spectra. The surface morphologies of the QCM sensor before and after gas adsorption are characterized by AFM, which indicates mild swelling of the surface after adsorption and it is reversible.