Principles of electrospray ionization

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Electrospray ionization (ESI) is the predominant ionization method for chemical and biochemical analysis.
• ESI, coupled with mass spectrometry, allows detailed investigation of liquid sample molecular composition.
• It enables ionization of diverse chemical substances, irrespective of mass, including large non-covalent protein complexes.

Purpose of the Study:

• To explore the underlying ionization mechanism of electrospray ionization.
• To discuss ionization characteristics linked to the mechanism.
• To describe the possibilities and limitations of measuring association constants for bivalent non-covalent complexes.

Main Methods:

• Review of electrospray ionization principles and applications.
• Analysis of typical mass spectra from peptides, proteins, and non-covalent complexes.
• Discussion of quantitative aspects of ESI spectra.

Main Results:

• ESI's high ionization efficiency has transformed biomolecular sciences, facilitating high-throughput identification and quantification of trace proteins.
• The review details the ionization mechanism and related characteristics.
• Quantitative analysis of spectra is highlighted, with examples of peptides, proteins, and complexes.

Conclusions:

• Electrospray ionization is a versatile and powerful technique for analyzing a wide range of molecules, including large biomolecular assemblies.
• Understanding the ionization mechanism is crucial for optimizing its application in various scientific fields.
• ESI offers significant potential for studying molecular interactions, such as measuring association constants of non-covalent complexes.