Electrospray ionization mass spectrometry principles

SMITH, R.D., LOO, J.A, OGORZALEK-LOO, R.R., BUSMAN, M., UDSETH, H.R., Principles and practice of electrospray ionization-mass spectrometry for large polypeptides and proteins, Mass Spec. Rev., 1991,31,472-485. 

Reviews covering the basic principles behind electrospray ionization mass spectrometry,and applications in inorganic, coordination,and organometallic chemistry have appeared. 

Reetz et al. [103] extended this approach. He reported the principle of a method based on electrospray ionization mass spectrometry (ESI-MS) enabling the determination of enantioselectivity of catalytic or stoichiometric asymmetric reactions. The method involves the reaction of a chiral reagent or catalyst with an equimolecular mixture of pseudo enantiomers, one isotopically labelled and the other non-labelled, simulating a racemate. 

Electrospray Ionization (ESI) The principle of generating ions of macromolecules by means of electrospray, a phenomenon that was described by French physicists as early as the 18th century as charged water spraying (Fig. 2.2), was reported in 1968, when Dole and co-workers studied Molecular Beams of Macroions without mass spectrometry. In 1984, the utility of ESI for the production of ionized... 

For detection of carbohydrates in principle, ultraviolet (UV), laser-induced fluorescence, refractive index, electrochemical, amperometric, and mass spec-trometric detection can be used. Mass spectrometry, with its various ionization methods, has traditionally been one of the key techniques for the structural determination of proteins and carbohydrates. Fast-atom bombardment (FAB) and electrospray ionization (ESI) are the two on-line ionization methods used for carbohydrate analysis. The ESI principle has truly revolutionized the modern mass spectrometry of biological molecules, due to its high sensitivity and ability to record large-molecule entities within a relatively smaU-mass scale. 

Techniques for the Ionization of Molecules The measurability of molecules by MSI is enabled through the local desorption and ionization of the molecules from a surface. In theory, all types of molecules that can undergo these two chemical processes can be measured. Many techniques have been developed or adapted to achieve desorption and ionization of molecules from surfaces, but three different desorption/ioniza-tion techniques made their way to commercially available products. The acronyms of these technologies are desorption electrospray ionization (DESI), MALDI, and secondary ion mass spectrometry (SIMS). The principles of these three methods and a comparison of their possibilities and limitations are outlined throughout this section and summarized in Figure 1 and Table 2, respectively. 

Over the years, many different approaches based on these two basic principles have been developed.4 9 We decided to focus on developing an approach to transfer analytes by coupling capillary tubing with electrospray ionization devices. From this basic design principle, we were able to develop a simple three-position device for the analysis of proteomic samples by mass spectrometry.7,10 We developed this principle further into an automated nine-position device,6 and to perform frontal analysis separations of peptides.11 This chapter reviews these early developments in coupling microfabricated devices to mass spectrometers. 

Other Techniques. A growing technique related to lc/ms and regarded as complementary to it is that of capillary zone electrophoresis/mass spectrometry (cze/ms) (22). Using cze/ms, high resolution separation of water-soluble compounds is accompHshed by the principles of electrophoresis (qv). The sample is then coupled to the mass spectrometer by electrospray ionization (23) or a fast atom bombardment interface (fab) to produce molecular ions (24). Biotechnology applications of cze/ms have great potential (25). 

The introduction of Matrix-Assisted Laser Desorption/Ionization (MALDI) and Electrospray Ionization (ESI) (Chapter 1) has dramatically increased the mass range for molar mass analyses by mass spectrometry. In principle, both techniques are able to produce intact quasi-molecular ions of polymers with high molar mass (>100,000 Da). 

Wilm, M. 2011. Principles of electrospray ionization. Mol. Cell Proteomics 10 1. El-Aneed, A., Cohen, A., and Banoub, J. 2009. Mass spectrometry, review of the basics Electrospray, MALDl, and commonly used mass analyzers. Appl. Spectrosc. Rev. 44 210-230. 

Figure 2.16. Basic components of electrospray ionization. (Reproduced from C. Dass, Principles and Practice of Biological Mass Spectrometry, Wiley-Interscience, 2001.)...

See also Electrophoresis Overview Principles. Fluorescence Overview Instrumentation. Mass Spectrometry Overview Atmospheric Pressure Ionization Techniques Electrospray. 

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