Synchronized dual-polarity electrospray ionization mass spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Ionization Techniques

Background:

• Electrospray ionization (ESI) is a crucial technique in mass spectrometry.
• Conventional ESI has limitations in flow rate range and sensitivity for certain applications.
• Dual-polarity (DP) ESI offers a potential advancement for ESI-MS.

Purpose of the Study:

• To describe the synchronized dual-polarity (DP) electrospray ionization (ESI) method.
• To demonstrate the first DP ESI mass spectra using two mass spectrometers.
• To evaluate the performance of DP ESI compared to conventional ESI.

Main Methods:

• Development of a single electrosprayer capable of producing stable double Taylor cones using counter electric voltages of opposite polarities.
• Optimization of extraction voltages and liquid flow rates for DP ESI.
• Acquisition of synchronized DP ESI mass spectra using electrospray calibrants in methanol solution.

Main Results:

• Stable double Taylor cones were successfully generated.
• DP ESI required higher extraction voltages but operated effectively over a wider liquid flow rate range (three times) than conventional ESI.
• Emission currents from the two cones neutralized in pure methanol, resulting in no net current drawn from the sprayer.
• Synchronized DP mass spectra were obtained, demonstrating the feasibility of the method.
• Conventional electrospray of bovine insulin showed satisfactory sensitivity and stability for routine analysis.

Conclusions:

• The synchronized DP-ESI method is a viable technique for simultaneous mass analysis.
• DP-ESI expands the operational parameters of ESI, particularly the liquid flow rate range.
• This method holds promise for enhanced analytical throughput and applications in mass spectrometry.