Facile Improvement of Negative Ion Mode Electrospray Ionization Using Capillary Vibrating Sharp-Edge Spray Ionization

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Electrospray ionization (ESI) performance is hindered by corona discharge with 100% aqueous solutions, especially in negative ion mode.
• This discharge limits the application of native mass spectrometry requiring aqueous environments.
• Existing methods using nebulization gas have limitations in mitigating discharge effectively.

Purpose of the Study:

• To develop a simple and cost-effective instrumentation method to improve ESI performance in negative ion mode.
• To overcome the challenges posed by corona discharge in aqueous solutions for mass spectrometry.
• To enhance signal intensity and signal-to-noise ratio for various analytes.

Main Methods:

• A novel capillary vibrating sharp-edge spray ionization technique was developed.
• A fused silica capillary emitter was attached to a vibrating glass slide.
• The method was tested with various analytes including DNA, peptides, proteins, and oligosaccharides in aqueous solutions.

Main Results:

• The vibrating capillary method significantly improved signal quality compared to standard ESI.
• Achieved 10-100 fold enhancement in signal intensity and 3-10 fold improvement in signal-to-noise ratio.
• Demonstrated successful native mass spectrometry analysis of proteins and G-quadruplex DNA.

Conclusions:

• The capillary vibrating sharp-edge spray ionization is a simple, low-cost, and effective method to enhance ESI performance in negative ion mode.
• This technique offers superior analytical performance for biomolecules in aqueous solutions.
• The method holds significant potential for widespread adoption in native mass spectrometry.