Mass spectrometry MALDI-based ionization

An analytical method based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was applied to provide information on the structure of copolymer 29, for example, repeat units and end groups <2002ANC6252>. 

Mass spectrometry methods based on soft ionization techniques, 59,61,88,89 matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF), have been successfully applied for the direct analysis of grape and wine extracts and for monitoring flavonoid reactions in model solution studies. They give access to the molecular weights of the different species present in a fraction or extract and, through fragmentation patterns, provide important information on their constitutive units. Description of the various MS techniques can be found in Chapters 1 and 2. 

Aptamers hold great promise as molecular recognition tools for their incorporation into analytical devices, and in particular, they can be used as immobilized ligands in separation technologies (Clark and Remcho, 2002), as affinity probes in capillary electrophoresis-based quantitative assays (Kotia and McGown, 2000), in affinity matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS)(Dick and McGown, 2004), and as biocomponents in biosensors (Tombelli et al., 2005). Other aptamer-based bioanalytical applications have been reviewed (Yon et al., 2003 Mukhopadhyay, 2005). 

The method of choice for elucidating chemical stmctures is NMR spectroscopy, supplemented by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). In addition, a multitude of chromatographic and light-scattering methods provide access to the molecular weights and solution properties of these macromolecules. Based on these methods, a detailed understanding of the structure of hb polymers has been acquired since their discovery however, there remain a number of open questions that must be answered, mainly by method adaptation and development. 

This chapter describes a step-by-step protocol for top-down proteomic identification of protein biomarkers of bacterial food-borne pathogens using matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-TOF-MS/MS) and web-based software developed at the Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture (USDA). 

This review provides an up-to-date overview of the application of analytical procedures based on MS for the characterization of organic natural materials in archaeological and historical objects. Applications that feature the use of gas chromatography/mass spectrometry (GC/MS), Py-GC/MS, high performance liquid chromatography combined with mass spectrometry (HPLC/MS), and direct MS analysis such as matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectrometry (ESI-MS), and direct exposure mass spectrometry (DE-MS) are sununarized to highlight the different information provided by each of the various analytical approaches. Case studies and examples are also presented and include a description of the molecular markers and of the molecular profiles that are used to identify the original materials. 

Agapito et al. ° applied fuzzy logic to an array of semiconductor gas sensors to analyze different atmospheres for the different gases and Otto et al. developed a scheme based on the principles of fuzzy logic that makes use of various pieces of information available either from spectroscopic knowledge or from the particular spectrum that requires evaluation. A fuzzy expert system has also been successfully developed for the automated qualitative and semiquantitative interpretation of X-ray diffraction spectra/ automation of matrix-assisted laser desorption-ionization mass spectrometry (MALDI), and for polymer analysis. 

In this chapter, the lipidomics approaches developed based on the electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) technologies (see Chapter 2) are described. Although matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has played many important roles in lipidomics and is also discussed in the chapter, it is no doubt that the majority of the platforms for lipidomics analysis currently used are based on ESI-MS in conjunction with MS/MS analyses. 

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