Fragmentation matrix assisted laser desorption/ionization mass

Fundamentals of Fragmentation Matrix Assisted Laser Desorption/Ionization Mass Spectrometry... 

Mark-Honwink eqnation Relates limiting viscosity number (LVN) to molecular weight LVN = KM . matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) MS in which the sample is placed in a matrix that contains a strong ultraviolet (LTV) absorber chosen to match the UV absorption of the laser, which allows the molecules to become volatilized with minimal fragmentation. 

Keki, S., Deak, G., and Zsuga, M., Fragmentation study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, using post-source decay matrix-assisted laser desorption/ionization mass spectrometry, J. Mass Spectrom., 36, 1312, 2001. 

D. J. Harvey, T. J. P. Naven, B. Kiister, R. H. Bateman, M. R. Green, and G. Critchley, Comparison of fragmentation modes for the structural determination of complex oligosaccharides ionized by matrix-assisted laser desorption/ionization mass spectrometry, Rapid Commun. Mass Spectrom., 9 (1995) 1556-1561. 

Lehmann, W. D. (1996). Protease-catalyzed incorporation of 180 into peptide fragments and its application for protein sequencing by electrospray and matrix-assisted laser desorption/ ionization mass spectrometry. Electrophoresis 17, 945-953. 

We have named our approach Eragmentation Matrix-Assisted Laser Desorption/ Ionization mass spectrometry, or simply E MALDI MS, because it is the fragmentation fragments that are emphasized in the study. The technique should be applicable to any solid when the proper operating conditions are employed. 

S. D. Patterson and V. Katta, Prompt fragmentation of disulfide-linked peptides dnr-ing matrix-assisted laser desorption ionization mass spectrometry. Anal. Chem. 66, 3727-3732 (1994). 

Dissociation and ionization by means of one or several lasers. Sensitive detection of fragments and ions with resonance photoionization and mass spectrometric techniques (tunable lasers). Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) with pulsed ablating laser sources. High lateral resolution enables molecular microprobing of biological cell compounds... 

Wada, Y. (1998) Separate analysis of complementary strands of restriction enzyme-digested DNA. An application of restriction fragment mass mapping by matrix-assisted laser desorption/ ionization mass spectrometry. J. Mass Spectrom., 33 (2), 187 192. 

Despite these demonstrations, our group presented the first systematic calculations to assess the absolute identifying power or phylogenetic classifying utility of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) when applied to RNase Ti or RNase A-generated fragments from large 16S rRNA sequence data sets [71-72]. 

Harvey, D.J. Naven, T.J.P. Kusler, B. Bateman, R. Green, M.R. Critchley, G. Comparison of Fragmentation Modes for the Strucmral Determination of Complex Oligosaccharides Ionized hy Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry. Rapid Commun. Mass Spectrom. 1995,9,1556-1561. 

Of these MSI techniques, matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is a soft ionization technique which does not produce fragments, or, at least, produces fewer ions fragments. In addition, its high sensitivity, accuracy, and spatial resolution made it suitable to measure the composition of compounds or biomacromolecules. So it can determine the distribution of peptides, proteins, or other chemicals and so on within thin slices of biological samples. Robinson et al. used MALDI-MS to measure the localization of water-soluble carbohydrates in wheat stems in situ and their method (Figure 10.26) may be useful for researchers of metallomics to carry out the study between metal or non metal and organism. 

Matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS) MALDI-MS technique enables ionization a broad range of materials, with high sensitivity, broad mass range of materials, fast sample preparation, and the absence of fragmentation. 

Most biochemical analyses by MS use either electrospray ionization (ESI) or matrix-assisted laser desorption ionization (MALD1), typically linked to a time-of-flight (TOF) mass analyzer. Both ESI and MALDl are "soft" ionization methods that produce charged molecules with little fragmentation, even with biological samples of very high molecular weight. 

MALDI (Section 12.4) Matrix-assisted laser desorption ionization a mild method for ionizing a molecule so that fragmentation is minimized during mass spectrometry. 

Tandem mass spectrometry (MS/MS) is a method for obtaining sequence and structural information by measurement of the mass-to-charge ratios of ionized molecules before and after dissociation reactions within a mass spectrometer which consists essentially of two mass spectrometers in tandem. In the first step, precursor ions are selected for further fragmentation by energy impact and interaction with a collision gas. The generated product ions can be analyzed by a second scan step. MS/MS measurements of peptides can be performed using electrospray or matrix-assisted laser desorption/ionization in combination with triple quadruple, ion trap, quadrupole-TOF (time-of-flight), TOF-TOF or ion cyclotron resonance MS. Tandem... 

Mass spectroscopy is a useful technique for the characterization of dendrimers because it can be used to determine relative molar mass. Also, from the fragmentation pattern, the details of the monomer assembly in the branches can be confirmed. A variety of mass spectroscopic techniques have been used for this, including electron impact, fast atom bombardment and matrix-assisted laser desorption ionization (MALDI) mass spectroscopy. 

Al-Saad, K. A. Zabrouskov, V. Siems, W. F. Knowles, N. R. Hannan, R. M. Hill, H. H. Matrix assisted laser desorption/ionization time-of-flight mass spectrometry of lipids ionization and prompt fragmentation patterns. Rapid Comm. Mass Spec-trom. 2003,17, 87-96. 

Experimental considerations Sample preparation and data evaluation are similar to membrane osmometry. Since there is no lower cut-off as in membrane osmometry, the method is very sensitive to low molar mass impurities like residual solvent and monomers. As a consequence, the method is more suitable for oligomers and short polymers with molar masses up to (M)n 50kg/mol. Today, vapour pressure osmometry faces strong competition from mass spectrometry techniques such as matrix-assisted laser desorption ionisation mass spectrometry (MALDI-MS) [20,21]. Nevertheless, vapour pressure osmometry still has advantages in cases where fragmentation issues or molar mass-dependent desorption and ionization probabilities come into play. 

Several original papers must be mentioned that deal with mass spectrometric techniques which the numerous reviews do not comprise. Kaufmann and coworkers268,288 studied the mass spectrometric analysis of carotenoids and some of their fatty acid esters using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and its post-source-decay (PSD) variant. Some advantages concerning the thermal instability and limited solubility were discussed, but the fragmentation paths of the carotenoid cations were found to be essentially the same as those observed with conventional techniques. 

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