An Introduction to Mass Spectrometry Ionization: An Excerpt from The Expanding Role of Mass Spectrometry in Biotechnology , 2nd ed.; MCC Press: San Diego, 2005
Year: 2004
Type: article
Abstract: Mass spectrometry has been described as the smallest scale in the world, not because of the mass spectrometer's size but because of the size of what it weighs-molecules.Over the past decade, mass spectrometry has undergone tremendous technological improvements, allowing for its application to proteins, peptides, carbohydrates, DNA, drugs, and many other biologically relevant molecules.Due to ionization sources such as electrospray ionization and matrix-assisted laser desorption/ionization (MALDI), mass spectrometry has become an irreplaceable tool in the biological sciences.This chapter provides an overview of mass spectrometry, focusing on ionization sources and their significance in the development of mass spectrometry in biomolecular analysis.A mass spectrometer determines the mass of a molecule by measuring its mass-to-charge ratio (m/z).Ions are generated by inducing either the loss or gain of a charge from a neutral species.Once formed, ions are electrostatically directed into a mass analyzer where they are separated according to m/z and finally detected.The result of molecular ionization, ion separation, and ion detection is a spectrum that can provide molecular mass or even structural information.An analogy can be drawn between a mass spectrometer and a prism, as shown in Figure 1.In the prism, light is separated into its component wavelengths, which are then detected with an optical receptor such as visualization.Similarly, in a mass spectrometer, the generated ions are separated in the mass analyzer, digitized, and detected by an ion detector (such as an electron multiplier; see chap.2). WHAT IS MASS SPECTROMETRY?John B. Fenn, the originator of electrospray ionization for biomolecules and the 2002 Nobel Laureate in Chemistry, probably gave the most apt answer to this question: Mass spectrometry is the art of measuring atoms and molecules to determine their molecular weight.Such mass or weight information is sometimes sufficient, frequently necessary, and always useful in determining the identity of a species.To practice this art one puts charge on the molecules of interest, i.e., the analyte, then measures how the trajectories of the resulting ions respond in vacuum to various combinations of electric and magnetic fields.Clearly, the sine qua non of such a method is the conversion of
Author: Gary Siuzdak
Institution: Scripps Research Institute
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2094512102