The copolymerized propylene-butyl, of which the ''solubility parameter'' al
most coincides with that of harmful gases such as toluene, xylene, diethyet
her, chloroform and acetone, is chosen as a material of the sensing membran
e coated on the quartz resonator. It is found that copolymerized propylene-
butyl-film-coated quartz resonator microbalance gas sensor exhibits high se
nsitivity and excellent selectivity for these harmful gases, especially for
toluene and xylene gas, suggesting that the "solubility parameter" is effe
ctive to the functional design of the sensing membrane of quartz resonator
gas sensors. (C) 2000 Elsevier Science S.A. All rights reserved.