Reaction-Based Amine and Alcohol Gases Detection with Triazine Ionic Liquid Materials

• Main Authors: Hsin-Yi Li, Yen-Ho Chu
• Format: Article
• Language: English
• Published: MDPI AG 2019-12-01
• Series: Molecules
• Subjects: ionic liquid; nucleophilic aromatic substitution; quartz crystal microbalance; amine gas detection; alcohol gas analysis
• Online Access: https://www.mdpi.com/1420-3049/25/1/104

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., &#916;<i>F</i> = &#8722;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.