Surface Acoustic Wave Sensor Response and Molecular Modeling: Selective Binding of Nitrobenzene Derivatives to (Aminopropyl)triethoxysilane

A number of derivatives of nitrobenzene have been found to bind selectively to a surface acoustic wave sensor treated with (aminopropyl)triethoxysilane. The relative binding affinities, measured by analyzing the frequency shift over time, exhibit response behaviors ranging from reversible to irreversible. These results can be explained in terms of a molecular orbital AM1 study of the binding behavior of the different analytes to the (aminopropyl)triethoxysilane film. The theoretical calculations indicate that differences in hydrogen bond strength and dipole moment are responsible for the observed selectivity.