Mass Spectrometry

Use of ECD and ETD Fragmentation Mechanisms for Peptide Sequencing

In the previous instalment of MS Solutions, I described some of the problems encountered with collisionally-activated dissociation (CAD) of peptides when used in MS/MS sequencing experiments. We noted that the number and type of structurally...

The Importance of Multiple-Charge Ion Precursors in Peptide MS/MS Sequencing

We typically think of a mass spectrum as consisting of a precursor ion at high m/z and a series of increasingly lower m/z product (fragment) ions. These types of mass spectra are shown in training courses and textbooks as didactic examples...

Determination of Intact Protein Molecular Mass from Multiple-Charge Electrospray Mass Spectra

In two previous instalments of MS Solutions, I discussed the sequencing of simple, single-charge peptide ions using MS/MS. In this and another upcoming edition I am going to discuss the use of multiple-charge ions in protein and peptide analysis.

NIST 11: What’s New and What Value Does it Offer? Part 5

Structural Identification of Unknowns from Spectra Obtained Using LC/MS and CAD Techniques and EI Mass Spectral Database.

NIST 11: What’s New and What Value Does it Offer? Part 4

This installment in the series on NIST 11 (National Institute of Standards and Technology) is about the Incremental Name Search , replicate spectra, and the NIST GC Methods, and Retention Index Database.

NIST 11: What’s New and What Value Does it Offer? Part 3

The previous two installments provided information on the NIST (National Institute of Standards and Technology)/EPA/NIH Mass Spectral Database, past and present, and on the use of the NIST MS Search Program in identifying a compound from its mass...

NIST 11: What’s New and What Value Does it Offer? Part 2

NIST 11 (EPA/EPA/NIH Mass Spectral Database of Electron Ionization Data, GC Method/Retention Index Databases, A Database of Spectra Obtained Using MS/MS Techniques, v.2.0g of the NIST MS Search Program, MS Interpreter v.2, and AMDIS) What’s New...

NIST 11: What’s New and What Value Does it Offer? Part 1

The NIST 11 (National Institute of Standards and Technology) Mass Spectral Database, the successor to the NIST 08, is a fully evaluated collection of electron ionization (EI) Mass Spectra, which also includes a growing number of MS/MS Spectra and GC...

Peptide Sequencing with Electrospray LC/MS Part 2: Interpretation of a Simple Spectrum

In the previous MS Solutions we discussed MS/MS fragmentation of polypeptides, the types of ions formed, and the mechanism of their formation. In this part we will examine a tandem mass spectrum of a simple polypeptide and step through an...

Peptide Sequencing with Electrospray LC/MS Part 1: Ion Types and Nomenclature

One of the most significant and important applications for mass spectrometry is the sequencing of polypeptides by electrospray LC/MS. An error in the sequence or the substitution of one amino acid with another can completely alter the biological...

Molecular Weight and the Nominal Mass, Monoisotopic Mass and Average Molar Mass

Mass associated with chemical formulae is different for those working in mass spectrometry as compared to those working in other fields of chemistry and in physics.

The Role of Isotope Peak Intensities Obtained Using Mass Spectrometry in Determining an Elemental Composition, Part 2

An illustrative example of the use of isotope peak ratios to determine an elemental composition.

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