Fast Chemical Analysis of Droplets Unlocked by Ultra-Fast Ion Mobility Spectrometry

Area of Science:

• Analytical Chemistry
• Chemical Physics
• Biotechnology

Background:

• Ion mobility spectrometry (IMS) offers compact, cost-effective chemical analysis.
• High-throughput analysis is crucial for screening and complex sample characterization.
• Integrating microfluidics with IMS can enhance speed and sample handling.

Purpose of the Study:

• To couple high-throughput droplet microfluidics with ultra-fast ion mobility spectrometry.
• To develop a label-free method for comprehensive analysis of droplet contents at high speeds.
• To demonstrate the utility of this combined technique for reaction screening.

Main Methods:

• Utilized a custom electrospray interface and a monolithic fused-silica droplet generator chip.
• Integrated these components with an ultra-fast ion mobility spectrometer.
• Developed droplet-based high-throughput ion mobility spectrometry (DHT-IMS) for analyzing individual droplets in segmented flow.

Main Results:

• Achieved chemical analysis of individual droplets at speeds up to 120 Hz.
• Demonstrated exceptionally short cycle times of less than 2 ms for spectral capture.
• Successfully applied DHT-IMS for reaction screening in nanoliter droplets, including a hydrazone formation reaction.

Conclusions:

• The coupling of droplet microfluidics and ultra-fast IMS provides a powerful platform for high-speed spectrometric analysis.
• DHT-IMS enables label-free, comprehensive analysis of droplet contents with high throughput.
• This technique shows significant potential for applications such as reaction screening and chemical analysis.