Selective piezoelectric odor sensors using molecularly imprinted polymers

Molecular imprinting technique has been used to create sensors with a prede termined selectivity for molecules in the gas phase. Piezoelectric quartz c rystals coated with a 2-methylisoborneol (MIB) imprinted polymer gave respo nses which were consistently 5-10 Hz (1.1-1.3 times) higher than those of s ensors coated with a-non-imprinted polymer. Geosmin, another tertiary alcoh ol odorant with an earthy odor resembling, and often accompanying MIB, prod uced almost equal responses on either imprinted- or non-imprinted sensors. A number of other odorants were examined and their responses to the non-imp rinted sensors were found to be similar to or greater than their responses to the imprinted sensors. The responses of MIB to the imprinted sensors wer e always the highest, while other odorants produced equal or higher respons es using the non-imprinted sensor. The sensor has a detection limit of ca. 5 mg l(-1) and a dynamic range of at least 1000 mg l(-1). When the time tak en for the sensor to stabilize is used as the response, instead of the freq uency change, the detection limit is lowered to ca. 200 mu g l(-1). (C) 199 9 Elsevier Science B.V. All rights reserved.