ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Mass spectrometry of isoleucine amino acid under electron impact ionization

Alexander V. Papp, Anatoly M. Zavilopulo, Anatoly M. Mylymko, and Eugene Yu. Remeta

Institute of Electron Physics, Ukr. Nat. Acad. Sci., Uzhhorod, Ukraine

E-mail: pappalex13@gmail.com

Received: 10 December 2024  Accepted: 21 April 2025

Abstract:

This study provides novel insights into the mass spectrometric behavior of isoleucine—a nonpolar aliphatic amino acid—under electron impact ionization conditions. Employing a monopole mass spectrometer, we analyzed the mass spectra and temperature-dependent ion fragment yields within the 0–135 Da range. Detailed mapping of the fragmentation pathways revealed that the predominant dissociation channel involves the cleavage of the C–Cα bond, resulting in the formation of a neutral COOH fragment. Temperature-dependent analyses indicate that ionization efficiency increases with elevated energy states. These findings contribute to a deeper understanding of biomolecular ionization mechanisms, with potential applications in biochemistry and radiobiology. Understanding the ionization and fragmentation behavior of isoleucine is crucial for elucidating fundamental processes in biological systems, such as protein degradation and metabolism. Moreover, these insights are valuable for radiation chemistry, where ion-induced fragmentation plays a key role in the molecular alterations caused by radiation exposure.

Graphical Abstract

Keywords: Analytical Biochemistry; Electron Paramagnetic Resonance Spectroscopy; Low- and highly-charged ions; Mass Spectrometry; Proteomics; Collision processes involving bio-macromolecules; Biomolecules; Isoleucine; Electron ionization; Mass spectrum; Fragmentati

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04081-w

Chemical Papers 79 (7) 4611–4621 (2025)