Mass spectrometry is a powerful analytical technique often used for the identification of unknown compounds such as small organic molecules, nucleotides, oligonucleotides, and peptides as well as proteins. A mass spectrometer separates and measures ions by their mass-to-charge (m/z) ratios. In biomolecular analysis experiments, mass spectrometry provides accurate molecular weight information on sub picomole amounts of biological molecules. Modified and unmodified molecules, such as oligonucleotides, peptides, and proteins, can be analyzed.

Historically, mass spectrometers were limited to the analysis of small, volatile molecules. However, in the last two decades, powerful mass spectrometers have been developed that overcame limitations in the mass range of mass spectrometers, and difficulties in inducing larger molecules into the gas phase including the complexity of the instruments. Two ionization techniques, electrospray ionization, and matrix-assisted laser desorption ionization, have emerged as the dominant techniques allowing now the analysis of large biomolecules including oligonucleotides, peptides and proteins, and complex mixtures of these.  Mass spectrometry, when used as a tandem technique, is now routinely able to yield partial to complete primary sequence information on carbohydrates, oligonucleotides, and peptides, as well as structural information for lipids. Table 1 contains a list of some masses for common elements. The most abundant isotope is shown.

Table 1:  Masses for common elements.

 
See also

Exact Masses of the Elements and Isotopic Abundances


To learn about the history of mass spectrometry go to the ASMS website 

Explanation of a Mass Spectrometer

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