Detection of Benzene and Volatile Aromatic Compounds by Molecularly Imprinted Polymer-Coated Quartz Crystal Microbalance Sensor

The detection of benzene and its analogues are extremely important but difficult without using expensive analytical instruments. The present work reports the detection of aromatic hydrocarbons, such as benzene, toluene, and isomers of xylene, using quartz crystal microbalance sensor. The surface of a silver-coated quartz crystal was coated with a simple solution drop coating method and thermally polymerized in an inert atmosphere for the formation of the sensing film. The polymer was synthesized by copolymerization of the optimum ratio of styrene, divinylbenzene, and tung oil at 90 degrees C with template. 1, 2, 3 trimethoxybenzene as template performed most efficiently for all the hydrocarbons. Linear calibration curves were observed for all the vapors in the concentration range between 5 and 250 ppm and sensitivities were obtained approximately as 1.645-2.605 Hz/ppm. For benzene, the sensitivity is 2.605 Hz/ppm, which is the highest amongst the reported literature. Thus, minimum concentration of benzene that can be detected is 0.98 ppm. The molecularly imprinted polymer structure and surface morphology were analyzed by FTIR spectroscopy, FESEM, and AFM. The sensitivity of detection of aromatic molecule in this paper by the molecularly imprinted polymer film is found to be the best amongst the reported literature.