| Summary: | We demonstrated in this work the use of affinity ionic liquids, <b>AIL 1</b> and <b>AIL 2</b>, for chemoselective detection of amine and alcohol gases on a quartz crystal microbalance (QCM). These detections of gaseous amines and alcohols were achieved by nucleophilic aromatic substitution reactions with the electrophilic 1,3,5-triazine-based <b>AIL 1</b> thin-coated on quartz chips. Starting with inexpensive reagents, bicyclic imidazolium ionic liquids <b>AIL 1</b> and <b>AIL 2</b> were readily synthesized in six and four synthetic steps with high isolated yields: 51% and 63%, respectively. The QCM platform developed in this work is readily applicable and highly sensitive to low molecular weight amine gases: for isobutylamine gas (a bacterial volatile) at 10 Hz decrease in resonance frequency (i.e., Δ<i>F</i> = −10 Hz), the detectability using <b>AIL 1</b> was 6.3 ppb. Our preliminary investigation on detection of the much less nucleophilic alcohol gas by <b>AIL 1</b> was also promising. To our knowledge, no example to date of reports based on nucleophilic aromatic substitution reactions demonstrating sensitive gas detection in these triazine ionic liquids on a QCM has been reported.
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