Ionization Methods in Mass Spectrometry | MALDI | ESI | EI | CI | FAB| Dr. Nagendra Singh | PENS#70

#massspectroscopy #ESI #MALDI

Ionization Methods in MS | Mass Spectroscopy | Dr. Nagendra Singh | PENS#70

In mass spectrometry, ionization refers to the production of gas phase ions suitable for resolution in the mass analyzer or mass filter. Ionization occurs in the ion source. There are several ion sources available; each has advantages and disadvantages for particular applications. For example, electron ionization (EI) gives a high degree of fragmentation, yielding highly detailed mass spectra which when skillfully analyzed can provide important information for structural elucidation/characterization and facilitate identification of unknown compounds by comparison to mass spectral libraries obtained under identical operating conditions. However, EI is not suitable for coupling to HPLC, i.e. LC-MS, since at atmospheric pressure, the filaments used to generate electrons burn out rapidly. Thus EI is coupled predominantly with GC, i.e. GC-MS, where the entire system is under high vacuum.

Hard ionization techniques are processes which impart high quantities of residual energy in the subject molecule invoking large degrees of fragmentation (i.e. the systematic rupturing of bonds acts to remove the excess energy, restoring stability to the resulting ion). Resultant ions tend to have m/z lower than the molecular mass (other than in the case of proton transfer and not including isotope peaks). The most common example of hard ionization is electron ionization (EI).

Soft ionization refers to the processes which impart little residual energy onto the subject molecule and as such result in little fragmentation. Examples include fast atom bombardment (FAB), chemical ionization (CI), atmospheric-pressure chemical ionization (APCI), electrospray ionization (ESI), desorption electrospray ionization (DESI), and matrix-assisted laser desorption/ionization (MALDI).

The Lectures are given Dr. Nagendra Singh aiming to spread basic understanding and awareness of biological molecules and reactions. Dr. Nagendra Singh finished his Doctoral and Post Doctoral studies from "All India Institute of Medical Sciences" (AIIMS) New Delhi. Dr. Singh has a vast experience of research and Teaching in the fields of Structure & Molecular Biology and Biochemistry, which also include Biomolecules, Proteomics, Protein Engineering and Drug Design.
Dr. Nagendra Singh currently works at the School of Biotechnology, Gautam Buddha University, Greater Noida, INDIA (http://www.gbu.ac.in/FacultyProfiles/.... He does research in Molecular Biology, Structural Biology and Biotechnology. His current research interest include 'Structural and functional characterization of proteins involved in RNA metabolism from human and microbial origin. Dr Singh has published over 70 research articles in international Journals of good repute. He has over 20 awards and honors on his name. Some of the awards include "National Academy of Sciences of India (NASI, Allahabad) young scientist award", UGC-NET, CSIR-JRF, GATE, Best Research Awards etc. Dr. Singh has participated and presented research work at over 50 National and International conferences world wide.
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