Nanoliter segmented-flow sampling mass spectrometry with online compartmentalization.

Area of Science:

• Analytical Chemistry
• Biotechnology
• Chemical Engineering

Background:

• Mass spectrometry (MS) is a powerful analytical technique.
• Efficient sample introduction and ionization are critical for MS sensitivity.
• Microfluidic devices offer precise control over small sample volumes.

Purpose of the Study:

• To develop a microfluidic system for direct sample introduction into a mass spectrometer.
• To enhance sample transfer efficiency and ionization in mass spectrometry.
• To achieve sensitive detection of analytes using a novel microfluidic interface.

Main Methods:

• A microfluidic device utilizing segmented flow in a two-phase system was designed.
• Aqueous droplets were delivered into a modified commercial mass spectrometer.
• Sample ionization was facilitated by a multipass infrared laser in the interface.

Main Results:

• Up to 96% sample transfer efficiency to the vacuum chamber was achieved.
• Low femtomole detection limits were obtained for diverse analytes (drugs, proteins).
• Ionization was insensitive to buffer salts and common matrices.

Conclusions:

• The developed microfluidic device enables highly efficient sample transfer and ionization for mass spectrometry.
• The system demonstrates robust performance with low detection limits and matrix tolerance.
• This approach offers a promising platform for sensitive analysis of small sample volumes.