Realizing nano electrospray ionization using disposable pipette tips under super atmospheric pressure

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Instrumentation

Background:

• Nano electrospray ionization (nanoESI) typically requires specialized, expensive glass capillaries with sub-10 μm tips.
• Achieving stable low flow rates (<100 nL/min) is crucial for sensitive and reproducible mass spectrometry analyses.
• Conventional nanoESI emitters are prone to clogging, especially with complex samples.

Purpose of the Study:

• To demonstrate the feasibility of using a disposable plastic pipette tip as a low-cost emitter for nanoESI.
• To evaluate the performance of this alternative emitter in terms of stability, sensitivity, and sample compatibility.
• To address the limitations of traditional nanoESI emitters, particularly clogging and cost.

Main Methods:

• Utilized a standard plastic gel loading pipette tip (100 μm inner diameter) as an electrospray emitter.
• Operated the electrospray under super-atmospheric gas pressure to maintain stable low flow rates (~10 nL/min) for aqueous solutions.
• Compared the performance of the plastic tip emitter with conventional metallized glass capillaries.

Main Results:

• Achieved stable electrospray ionization at ~10 nL/min using the plastic pipette tip, comparable to standard nanoESI emitters.
• Demonstrated equal sensitivity and long-lasting signals from small sample volumes.
• Observed reduced ion suppression effects, similar to nanoESI, due to small initial droplet size.
• Showcased improved resistance to clogging with complex samples compared to fine glass capillary emitters.

Conclusions:

• Disposable plastic pipette tips can serve as effective, low-cost alternatives for nanoESI.
• This method provides a robust and sensitive platform for mass spectrometry, particularly for challenging samples.
• The approach offers a practical solution for reducing instrument costs and improving sample throughput in analytical laboratories.