Electrospray Ionization Mass Spectrometry: A Technique to Access the Information beyond the Molecular Weight of the Analyte

TLDR

Electrospray ionization (ESI) is a soft technique that generates gas‑phase ions of large, thermally labile supramolecules without fragmentation, and extensive studies have investigated the mechanisms of charged species formation and the multiple charge states observed for proteins. This review aims to highlight recent developments and emerging directions in ESI‑MS research. ESI produces charged analytes that can be activated in the gas phase for tandem mass spectrometry, enabling detailed structural insights into the molecules. Over the past 25 years, ESI‑MS has evolved to probe diverse properties of biological molecules, as summarized in this review.

Abstract

The Electrospray Ionization (ESI) is a soft ionization technique extensively used for production of gas phase ions (without fragmentation) of thermally labile large supramolecules. In the present review we have described the development of Electrospray Ionization mass spectrometry (ESI-MS) during the last 25 years in the study of various properties of different types of biological molecules. There have been extensive studies on the mechanism of formation of charged gaseous species by the ESI. Several groups have investigated the origin and implications of the multiple charge states of proteins observed in the ESI-mass spectra of the proteins. The charged analytes produced by ESI can be fragmented by activating them in the gas-phase, and thus tandem mass spectrometry has been developed, which provides very important insights on the structural properties of the molecule. The review will highlight recent developments and emerging directions in this fascinating area of research.