Analytical Sciences

Microporous Organic–inorganic Nanocomposites as the Receptor in the QCM Sensing of Toluene Vapors

Ryo ISHII, Ryuichi NAGANAWA, Masateru NISHIOKA, and Taka-aki HANAOKA

National Institute of Advanced Industrial Science and Technology (AIST), 4-2-1 Nigatake, Miyagino, Sendai, Miyagi 983-0036, Japan

We have used novel microporous biphenylene-pillared layered silicates as receptors in a quartz crystal microbalance (QCM) for sensing toluene vapors. The silicate was successfully coated on a QCM electrode modified with 2-aminoethanethiol. The resultant electrode showed quantitative frequency responses due to enhanced adhesion between the silicate and the electrode. The silicate-coated electrodes also performed better than polystyrene-coated electrodes in terms of both sensitivity and reproducibility of the responses for toluene vapors exposures because the silicate has an organically-modified open-framework structure with a high surface area. In addition, the electrodes revealed the higher sensitivity for toluene vapors than those for alcohol vapors, suggesting selectivity toward sensing toluene vapors probably due to the π–π stacking interaction between biphenylene units and toluene molecules. Hence, we anticipate that the materials are promising to be used as receptors in QCM devices for sensing aromatic vapors.

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