Development of QCM Trimethylamine Sensor Based on Water Soluble Polyaniline

A rapid, sensitive, low-cost device to detect trimethylamine was presented in this paper. The preparation of water soluble polyaniline was firstly studied. Then the polyaniline was characterized via Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy and scanning electron microscopy (SEM). Based on the water soluble polyaniline film, a quartz crystal microbalance (QCM) sensor for trimethylamine detection was fabricated and its characteristics were examined. The sensor consisted of one quartz crystal oscillator coated with the polyaniline film for sensing and the other one for reference. Pretreated with trimethylamine, the QCM sensor had an excellent linear sensitivity to trimethylamine. Easily recovered by N2 purgation, the response of the sensor exhibited a good repeatability. Responses of the sensor to trimethylamine, ethanol and ethyl acetate were compared, and the results showed that the response was related to the polarity of the analyte vapor. Experimental result also showed that the sensitivity of the sensor was relatively stable within one month. The simple and feasible method to prepare and coat the polyaniline sensing film makes it promising for mass production.