Lecture

Mass Spectrometry: Ion Sources and Analyzers

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In course

PHYS-468: Physics of life

Life has emerged on our planet from physical principles such as molecular self-organization, thermodynamics, stochastics and iterative refinement. This course will introduce the physical methods to study life and will discuss the quantitative and physical ...

Description

This lecture on Mass Spectrometry covers the principles of ionization, mass sorting, and analysis according to mass/charge ratio. It explains the operation of various ion sources, analyzers, and detectors, such as Electron Ionization, MALDI, and Quadrupole Mass Filters. The instructor discusses the advantages and disadvantages of different ionization techniques, including Electron Spray Ionization and Chemical Ionization. The lecture also delves into the functioning of instruments like Linear Time-of-Flight and Reflectron Time-of-Flight mass analyzers, highlighting their capabilities and limitations.

Instructor

Henning Paul-Julius Stahlberg

Mission We use high-resolution cryo-electron microscopy to study neurodegeneration and other protein systems. We also develop novel imaging technology in the areas of electron microscopy hardware and applications, sample preparation, data collection schemes, and data analysis software systems. The Stahlberg group is supported by the University of Lausanne, Faculty of Medicine and Biology, and by the EPFL, Faculty of Basic Sciences, Physics Institute. The LBEM is a research laboratory of both UNIL and EPFL.

Official source

Ontological neighbourhood

Chemistry

Analytical chemistry: Mass spectrometry

Related concepts (32)

Electron ionization

Electron ionization (EI, formerly known as electron impact ionization and electron bombardment ionization) is an ionization method in which energetic electrons interact with solid or gas phase atoms or molecules to produce ions. EI was one of the first ionization techniques developed for mass spectrometry. However, this method is still a popular ionization technique. This technique is considered a hard (high fragmentation) ionization method, since it uses highly energetic electrons to produce ions.

Chemical ionization

Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. This was first introduced by Burnaby Munson and Frank H. Field in 1966. This technique is a branch of gaseous ion-molecule chemistry. Reagent gas molecules (often methane or ammonia) are ionized by electron ionization to form reagent ions, which subsequently react with analyte molecules in the gas phase to create analyte ions for analysis by mass spectrometry.

Tandem mass spectrometry

Tandem mass spectrometry, also known as MS/MS or MS2, is a technique in instrumental analysis where two or more mass analyzers are coupled together using an additional reaction step to increase their abilities to analyse chemical samples. A common use of tandem MS is the analysis of biomolecules, such as proteins and peptides. The molecules of a given sample are ionized and the first spectrometer (designated MS1) separates these ions by their mass-to-charge ratio (often given as m/z or m/Q).

Ion source

An ion source is a device that creates atomic and molecular ions. Ion sources are used to form ions for mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines. Electron ionization Electron ionization is widely used in mass spectrometry, particularly for organic molecules. The gas phase reaction producing electron ionization is M{} + e^- -> M^{+\bullet}{} + 2e^- where M is the atom or molecule being ionized, e^- is the electron, and M^{+\bullet} is the resulting ion.

Ionization

Ionization (or ionisation) is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules and ions, or through the interaction with electromagnetic radiation.

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