Imprinted polymer-based enantioselective acoustic sensor using a quartz crystal microbalance

An enantioselective chemical sensor has been designed and fabricated. The sensor is based on a molecularly imprinted polymer, serving as the recognition element, and a quartz crystal microbalance (QCM), used as the transducer. The polymer, imprinted with the chiral β-blocking drug S-propranolol, was cast as a thin permeable film onto a gold electrode deposited on the quartz crystal vibrator. The mass increase of the polymer due to analyte binding was quantified by piezoelectric microgravimetry with the QCM. The sensor was able to discriminate between the R- and S-propranolol enantiomers in acidified acetonitrile solutions owing to the enantioselectivity of the imprinted sites. Detectability of S-propranolol was 50 µmol dm–3. The general procedure developed here for preparation of the sensor can be adapted for fabrication of a range of different stable analytical sensing devices for numerous analytes by using conventional molecular imprinting protocols.