MALDI mass spectrometry matrix

Wigge, P. A., Jensen, O. N., Holmes, S., Soues, S., Mann, M., and Kilmartin, J. V. (1998). Analysis of the Saccharomyces spindle pole by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. J. Cell Biol. 141, 967-977. 

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. 

A recently developed technique that has found extensive use in the characterization of dendrimers, specifically in determining the purity and monodispersity of these novel materials, has been matrix-assisted laser desorption/ionization (MALDI) mass spectrometry [16,17]. For dendrimers grown by the divergent strategy, incomplete functionalization of the periphery can lead to subsequent failure sequences and loss of strict dendritic growth. Observation and quantification of these defects is extremely difficult by other techniques, however MALDI mass spectrometry has been successfully employed by a variety of authors to... 

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has contributed remarkably to unravelling the termination and initiation steps of the styrene/CO copolymerisation catalysed by the highly active bis-chelated complex [Pd(bipy)2](Pp5)2 in TFE [40]. Chain-end group analysis of the material produced in the absence of BQ showed that the termination by P-H elimination is accompanied by three different initiators two palladium alkyls from Pd-H formed by reaction of the precursor with CO and water (a and b) and a palladium carboalkoxy species formed by reaction of the precursor with the fluorinated alcohol and CO (c) (Chart 7.4). The suppression of the chain-transfer by alcoholysis was proposed to be responsible for the enhanced stability of the palladium acyl intermediates and hence for the high molecular weight of the copolymers produced. 

In initial work, a total of 17 different ILs were evaluated by the solvation parameter model [8]. Ten of these ILs were comprised of imidazolium or pyrolidinium cations paired with different anions. Many of these compounds represent the traditional class of IL solvents that have been used extensively in organic synthesis reactions or in other analytical uses. The remaining seven ILs consisted of substituted ammonium cations that have proven to be successful analyte matrices in matrix-assisted laser desorption ionization (MALDI) mass spectrometry [11]. 

Wingerath, T., Stahl, W., Kirsch, D., Kaufmann, R., and Sies, H. 1996. Fruit juice carotenol fatty acid esters and carotenoids as identified by matrix-as-si sted laser desorption ionization (MALDI) mass spectrometry. J. Agric. Food Chem. 44 2006-2013. 

Fitzgeraldand MC, Smith LM. Mass spectrometry of nucleic acids the promise of matrix-assisted laser desorption-ionization (MALDI) mass spectrometry. Annu Rev Biophys Biomol Struct 1995 24 117-140. 

The ionization methods reported for IMS included MALDI [41,76-80], Secondary Ion Mass Spectrometry (SIMS) [19, 81-86], Matrix-enhanced (ME)-SIMS [87, 88], Desorption Electrospray Ionization (DESI) [89-99], Nanostructure Initiator Mass Spectrometry (NIMS) [100-102], Atmospheric Pressure Infrared MALDI Mass Spectrometry (AP-IR-MALDI-MS) [103], Laser Ablation-inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) [104-106], Laser Desorption Postionization (LDPI) [107], Laser Ablation Electrospray Ionization Mass Spectrometry (LAESI) [108, 109], and Surface-assisted Laser Desorption/ioniza-tion Mass Spectrometry (SALDI) [110-112], Another method was called probe electrospray ionization (PESI) that was used for both liquid solution and the direct sampling on wet samples. 

Fig. 2 (a) The optical image of a rat brain from a coronal section, (b) Matrix-assisted laser desorp-tion/ionization (MALDI)-mass spectrometry (MS)/MS images of astemizole in the rat brain slice without perfusion and (c) with perfusion cortex, hippocampus, corpus callosum, hypothalamic region, thalamus region, choroid plexus, dorsal third ventricle, and lateral ventricle are indicated by arrows, (d) MALDI-MS/MS images of M-14 metabolite of astemizole in the rat brain slice (Li et al. [152], Reproduced with permission from Future Science Ltd)... 

Meriaux C, Franck J, Wisztorski M, Salzet M, Fournier I (2010) Liquid ionic matrixes for MALDI mass spectrometry imaging of lipids. J Proteomics 73 1204-1218. doi 10.1016/j. jprot.2010.02.010... 

Agar N, Yang H, Carroll R, Lack P, Agar J (2007) Matrix solution fixation histology-compatible tissue preparation for MALDI mass spectrometry imaging. Anal Chem 79(19) 7416-7423. doi 10.1021/ac071460e... 

Development of a wide range of Surface MALDI mass spectrometry methods12 opens new possibilities in MS investigations of bio-interfacial phenomena, summarized recently as biological surface science . Thus, matrix-assisted laser desorption ionization mass spectrometry, and its variants, hold promise to help clarify the mechanisms of bio-activity of silica-based nanocomposites. 

Bahr, U., Karas, M., Hillenkamp, F. (1994) Analysis of Biopolymers by Matrix-Assisted-Laser-Des-orption/Ionization (MALDI) Mass Spectrometry, in Microcharacterization of Proteins (Kellner, R., Lottspeich, F., Meyer, H.E., Eds.). VCH, Weinheim Bayley, H., Knowles, J.R. (1977) Photoaffinity Labeling, Methods Enzymd. 46, 69-114. 

For peptide libraries, one solution to this problem uses matrix-assisted laser desorption ionization (MALDI) mass spectrometry to directly desorb and identify peptides from beads that were screened and found to be hits (33). This technique is called the termination synthesis approach. Because the peptide library compounds are analyzed directly, products with amino acid deletions or substitutions, side-reaction products, or incomplete deprotection are readily observed. Also, because there are no extra molecules used for chemical... 

The molecular masses of the RNase T1 proteins were determined by matrix-assisted laser desorption ionization (MALDI) mass spectrometry on a home-built spectrometer constructed in the laboratory of Dr. D. H. Russell (DepL of Chemistry, Texas A M University). The matrix solution was a-cyano-4-hydroxycinnamic acid (15 mg/mL) in methanol. Samples were ionized in a 20... 

Structural information obtained from these modem methods is complemented by fast atom bombardment (FAB) mass spectra [22] of both free and functionalized monosaccharides with a variety of functional groups such as thiols, nitro, keto, benzyl, azido, epoxy, esters, etc. FAB mass spectrometry is one of the most reliable and sophisticated techniques developed thus far. Moreover, one can predict the specific fragmentation pattern for the selected class of functionalized monosaccharides through the FAB method as well as the matrix assisted laser desorption ionization (MALDI) mass spectrometry method. 

Kaufmann, R. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry A novel anal3dical tool in molecular biology and biotechnology. J. Biotechnol. 1995, 41, 155-175. 

Figure 15.15. Comparasion of MALDI spectra of E. coli (strain ATCC 11775) grown in different laboratories, under the same experimental conditions. The asterisks on the bottom trace indicate common peaks in the two spectra.31,32 [Top trace reprinted, with permission, from Z. Wang, L. Russon, L. Li, D. C. Roser, and S. R. Long, Rapid Communications in Mass Spectrometry 12, 1998, 456 -64. Investigations of Spectral Reproducibility in Direct Analysis of Bacteria Proteins by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry . 1998 John Wiley Sons, Ltd. Bottom trace reprinted, with permission, from Catherine Fenselau and Plamen A. Demirev, Mass Spectrometry Reviews 20, 2001, 157-171. Characterization of Intact Microorganisms by Maldi Mass Spectrometry. Copyright 2002 by John Wiley Sons, Inc.]...

Various molecular and quasi-molecular ions can be formed under MALDI conditions. The formation of protonated analyte (A) molecules, [A -F H]+, is generally most important at least for samples containing slightly basic centres, such as the peptides and proteins, MALDI mass spectrometry of which is known to be most facile and reproducible. Therefore, proton transfer from the electronically excited, neutral or ionized, or protonated matrix species is considered to be crucial in the overall MALDI process . Notably, proton transfer can occur already in the condensed phase, followed by desorption of the preformed ions . However, the generation of the [A -F H]+ ions is believed to take place preferably in the so-called plume , that is, in the energized, short-hved and relatively dense vapour phase generated above the solid matrix upon excitation by the laser pulse. The actual proton donor species (be it one or several) in a given case is still a matter of... 

Powell, K.D. Wales, T.E. Fitzgerald, M.C. Thermodynamic Stability Measurements on Multimeric Proteins Using a New H/D Exchange- and Matrix-Assisted Laser Desorption/lonization (MALDI) Mass Spectrometry-Based Method, Protein Science 11, 841-851 (2002). 

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