Mass spectrometry (MS) technique : the must have basics

Name: Mass spectrometry (MS) technique : the must have basics
Rating: 4.2 (19 reviews)

Analyzing MS spectrum

Created byChemistry Ka

Last updated 6/2022

English

What you'll learn

Know the objective, constraints and principle of Mass spectrometry (MS) technique.
Understand the ionization step of any molecule using Electron-Impact (EI) ionization technique.
Identifiy, easily, the molecular ion by sntaching off the right electron.
Master the important fragmentation reactions : Heterolytic (sigma) cleavage, Homolytic (alpha) cleavage, and McLafferty rearrangement.
Identify the fragmentation process by loss of neutral molecule [Gamma cleavage]: case of alcohols (loss of water molecule)

Course content

1 section • 6 lectures • 1h 12m total length

Introduction2:56
Session 2 : Principles and basics18:36
Learn how mass spectrometry determines molecule masses by vaporizing the sample, ionizing it by electron impact, and analyzing molecular and isotope peaks and fragments to reveal composition.
Session 3 : Heterolytic cleavage - Fragmentation reaction14:22
Explore heterolytic cleavage in mass spectrometry, comparing sigma and alpha cleavage, lone pair and p-bond considerations, and how electronegativity guides which fragment forms the base peak and molecular ion.
Session 4 : Homolytic cleavage - Fragmentation reaction13:37
Explore homolytic alpha cleavage in mass spectrometry, distinguishing alpha versus sigma cleavage, identifying alpha carbon next to functional groups, and predicting fragment ions and isotope patterns in MS.
Session 5 : Gamma cleavage : Fragmentation reaction14:23
Examine gamma cleavage in mass spectrometry, a two-step fragmentation combining sigma and alpha cleavages in alcohols, leading to water loss and characteristic fragment masses (-18, -29, -57).
Session 6 : McLafferty rearrangement - Fragmentation reaction8:46

Requirements

Basics in organic chemistry.

Description

Spectrometry vs. Spectroscopy

Spectroscopy is a theoretical science that studies the interaction between matter and electromagnetic radiation, focusing on how matter absorbs energy. In contrast, spectrometry refers to the practical measurement of spectra and provides quantitative results.

Mass spectrometry (MS) is a type of spectrometry used to determine the masses of ions in a sample, allowing the identification of elemental composition and molecular structure. Understanding MS data requires knowledge of how ions are formed and fragmented.

Course scope and Level

This course introduces the fundamental principles of mass spectrometry with a focus on ion formation and fragmentation mechanisms used for spectrum interpretation. It is strictly designed for beginners with basic knowledge of analytical chemistry.

The course does not include training on MS equipment, instrument setup, or hands-on operation of a mass spectrometer. Instead, it concentrates on the conceptual understanding and interpretation of mass spectra.

The learning approach is progressive and explanatory, allowing beginners to build confidence step by step. Emphasis is placed on understanding common fragmentation pathways, recognizing characteristic ions, and developing logical strategies for spectrum interpretation. Numerous examples and guided exercises are provided to reinforce concepts and improve analytical skills. By the end of the course, learners will be able to interpret basic mass spectra independently while clearly understanding the theoretical limitations of the technique.

Who this course is for:

Beginners in analytical chemistry.