Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

High-Resolution Mass Spectrometry (HRMS)01:15

High-Resolution Mass Spectrometry (HRMS)

1.8K
The resolution of a mass spectrometer depends on the efficiency of separating ions with different ion masses. The mass of an atom is approximated to the sum of the masses of protons and neutrons inside, considering the masses of protons and neutrons as equal. However, the masses of the proton (1.6726 × 10−24 g) and neutron (1.6749 × 10−24 g) are not truly equal. There is a minor error in the expression of atomic masses relative to the simplest atom of hydrogen. For...
1.8K
Mass Spectrometry: Isotope Effect01:13

Mass Spectrometry: Isotope Effect

2.9K
Most elements exist in nature as a mixture of isotopes. The isotopes differ in weight due to their respective number of neutrons. The molecular weight of a molecule is different depending on the specific isotope of its elements involved. As a result, the mass spectrum of the molecule exhibits peaks from the same fragment at multiple positions. The positions of these mass signals depend on the difference between the molecular mass. Furthermore, the intensity of these signals is dependent on the...
2.9K
Atomic Mass01:52

Atomic Mass

65.9K
Atoms — and the protons, neutrons, and electrons that compose them — are extremely small. For example, a carbon atom weighs less than 2 × 10−23 g. When describing the properties of tiny objects such as atoms, we use appropriately small units of measure, such as the atomic mass unit (amu). The amu was originally defined based on hydrogen, the lightest element, then later in terms of oxygen. Since 1961, it has been defined with regard to the most abundant isotope of...
65.9K
Mass Spectrometry: Overview01:19

Mass Spectrometry: Overview

6.6K
Mass spectrometry is an analytical technique used to determine the molecular mass and molecular formula of a compound. The basic principle of mass spectrometry is to generate ions from the analyte molecule and measure these ion abundances against their molecular mass.  One common type of ionization, known as electrospray ionization or EI, bombards the analyte molecules in the gas phase with high-energy electron beams. The electron beams displace an electron from the molecule and leave...
6.6K
Mass Analyzers: Overview01:13

Mass Analyzers: Overview

983
The mass analyzer is a crucial component of the mass spectrometer. In the ionization chamber, the vaporized sample is bombarded with a high-energy electron beam to generate a radical cation and further fragment into neutral molecules, radicals, and cations. A series of negatively charged accelerator plates accelerate the cations into the mass analyzer. The mass analyzer separates ions according to their mass-to-charge (m/z) ratios and then directs them to the detector. The common types of mass...
983
Mass Spectrum01:23

Mass Spectrum

2.8K
A mass spectrum is the graphical representation of the relative abundance of the charged fragments in an analyte plotted against their mass-to-charge ratio (m/z). The plot's x axis represents the ratio of the mass of the charged fragment to the elementary charge it carries. The y axis of the plot represents the relative abundance of each charged species. The relative abundance is calculated from the signal intensity of each charged species recorded at the detector. The most intense signal...
2.8K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Unexpected Artifact Formation in Mass Spectrometric Analysis of Aniline under Atmospheric-Pressure Chemical Ionization.

Journal of the American Society for Mass Spectrometry·2025
Same author

Formation of Micelles by Nonionic Detergent Molecules Leads to the Breakthrough Peak in Reversed-Phase Ultraperformance Liquid Chromatography (UPLC).

Analytical chemistry·2024
Same author

Manipulating Non-Dissociative Transformations of Gaseous Ion Ensembles Prior to Ion-Mobility Separation.

Journal of the American Society for Mass Spectrometry·2024
Same author

Dependence of Collision-Induced Mass Spectra of Protonated Michler's Ketone on the Nature of LC-MS Mobile Phase.

Journal of the American Society for Mass Spectrometry·2023
Same author

Impact of Ambient Vapors on Spectra of 4-Nitroaniline Recorded under Atmospheric Solids Analysis Probe (ASAP) Mass Spectrometric Conditions.

Journal of the American Society for Mass Spectrometry·2023
Same author

Evidence of Gas-Phase Attachment of Molecular Oxygen to Deprotonated Hydroquinone During Ion-Mobility Mass Spectrometry.

Journal of the American Society for Mass Spectrometry·2022

Related Experiment Video

Updated: Oct 11, 2025

Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry
09:34

Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry

Published on: September 20, 2016

11.3K

Monoisotopic Mass?

Athula B Attygalle1, Julius Pavlov1, Josef Ruzicka2

  • 1Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States.

Journal of the American Society for Mass Spectrometry
|December 6, 2021
PubMed
Summary

The current definition of monoisotopic mass is flawed and should be abandoned. We propose using "isotopologue mass" for all species defined by a chemical formula.

Area of Science:

  • Chemical metrology
  • Analytical chemistry
  • Physical chemistry

Background:

  • The International Union of Pure and Applied Chemistry (IUPAC) currently defines monoisotopic mass based on the most abundant isotopes.
  • A proposed refinement restricts this definition to the most abundant stable isotopes.
  • This definition has limitations for elements with multiple abundant isotopes and large molecules like proteins.

Purpose of the Study:

  • To critically evaluate the current IUPAC definition of monoisotopic mass.
  • To highlight the inadequacies of the existing and proposed definitions.
  • To propose a new, unified terminology for isotopic mass determination.

Main Methods:

  • Critical analysis of the IUPAC definition of monoisotopic mass.

More Related Videos

A Method for Measuring Metabolism in Sorted Subpopulations of Complex Cell Communities Using Stable Isotope Tracing
07:41

A Method for Measuring Metabolism in Sorted Subpopulations of Complex Cell Communities Using Stable Isotope Tracing

Published on: February 4, 2017

8.6K
Subtyping of Campylobacter jejuni ssp. doylei Isolates Using Mass Spectrometry-based PhyloProteomics MSPP
09:43

Subtyping of Campylobacter jejuni ssp. doylei Isolates Using Mass Spectrometry-based PhyloProteomics MSPP

Published on: October 30, 2016

8.7K

Related Experiment Videos

Last Updated: Oct 11, 2025

Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry
09:34

Improved Polymerase Chain Reaction-restriction Fragment Length Polymorphism Genotyping of Toxic Pufferfish by Liquid Chromatography/Mass Spectrometry

Published on: September 20, 2016

11.3K
A Method for Measuring Metabolism in Sorted Subpopulations of Complex Cell Communities Using Stable Isotope Tracing
07:41

A Method for Measuring Metabolism in Sorted Subpopulations of Complex Cell Communities Using Stable Isotope Tracing

Published on: February 4, 2017

8.6K
Subtyping of Campylobacter jejuni ssp. doylei Isolates Using Mass Spectrometry-based PhyloProteomics MSPP
09:43

Subtyping of Campylobacter jejuni ssp. doylei Isolates Using Mass Spectrometry-based PhyloProteomics MSPP

Published on: October 30, 2016

8.7K
  • Examination of isotopic abundance data for various elements.
  • Assessment of the significance of monoisotopic mass for different molecular sizes.

    • Main Results:

    • The current definition of monoisotopic mass is inadequate as it excludes many elements and isotopically enriched species.
    • For large molecules, such as proteins, the concept of monoisotopic mass loses practical significance.
    • The proposed refinement based on stable isotopes also presents limitations.

    Conclusions:

    • The current IUPAC definition of monoisotopic mass is fundamentally flawed and should be discarded.
    • The term "isotopologue mass" offers a more accurate and universally applicable descriptor for species defined by a specific chemical formula.
    • Adopting "isotopologue mass" will enhance clarity and consistency in isotopic mass measurements.