Matrix-assisted laser desorption ionization mass spectroscopy

After device construction, structural and functional analysis are critical. One might argue that only the second issue matters, but structural data often give insights into why devices perform suboptimally, and provide important clues about how to improve device function. We routinely use protein analytics (matrix-assisted laser desorption-ionization mass spectroscopy, amino acid composition analysis, gel electrophoresis, Western blotting, circular dichroism, vari-... 

The low volatility of ILs makes them useful as solvents working under high vacuum, and together with their more amorphous solid analogs they are convenient in matrix-assisted laser-desorption/ ionization-mass spectroscopy (MALDI-MS) analysis.103104... 

MALDI-MS refers to matrix-assisted laser desorption-ionization mass spectroscopy, It is also called MALFI-TOF, because the mass spectrometer is a time-of-flight version. In this technique, the polymer is mixed with a molar excess of a salt, for cationization, and deposited on a probe surface. A UV laser is pulsed... 

Cryoscopy and ebulioscopy can be used for the measurement of Mn for polymers in a similar way to the application on smaller molecules, and the procedure is used mainly when Mn < 2 10. I LDI-MS (matrix-assisted laser desorption ionization-mass spectroscopy) allows the measurement of both Mn and M , as well as the molecular weight distribution, which indicates the variation of w, (weight fraction of the component i ), as a function of M,. 

The toluene-soluble fraction consists of a major product that has been identified as a CgQ-TEA monocycloadduct 7V-ethyl-rra/w-2, 5 -dimethyl-pyrrol-idino[3, 4 l,2][60]fullerene (14) by use of matrix-assisted laser desorption ionization mass spectroscopy and NMR methods [71]. It is interesting that the photochemical reaction actually results in the formation of a cycloadduct. This is unique to the fuilerene system because there have been no reports of cycloadducts in reactions involving nonfullerene acceptors [119-122], such as rra/is-stilbene. In the context of the classical photoinduced electron transfer-proton transfer mechanism [124], a two-step process for the formation of the cycloadduct has been proposed [71]. 

Matrix-assisted laser desorption—ionization mass spectroscopy is a convenient method for rapid and sensitive structural analysis of oligosaccharides (Harvey 1999). It was observed that MALDI TOE TOF mass spectrometric analysis reveal a series of masses (m/z) corresponding to pentose and hexose sugars... 

Wingerath, T. et al. (1999). Analysis of cyclic and acyclic analogs of retinol, retinoic acid, and retinal by laser desorption ionization-, matrix-assisted laser desorption ionization-mass spectrometry, and UV/Vis. spectroscopy. Anal. Biochem. 272(2) 232-242. 

Elucidation of degradation pathways and identification of transformation products (TPs) is of crucial importance in understanding their fate in the environment and requires the employment of advanced instrumental techniques. Analytical methods that can be used for this purpose include Uquid chromatography with diode array or fluorescence detector (LC-DAD/FL), nuclear magnetic resonance (NMR), infrared spectroscopy (IR), matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS), gas... 

SAMs of allgrlphosphonic acids (butylphosphonic acid, octylphosphonic acid, undecylphosphonic acid and octadecylphosphonic acid) on native niekel oxide allow substrates to be functionalized easily. Monolayer formation has been investigated by diffuse reflectance Fourier transform infrared spectroscopy, non-contact mode atomic force microscopy, contact angle measurements and matrix-assisted laser desorption ionization mass spectrometry. Cyclic voltammetry and electrochemical impedance spectroscopy studies showed that the monolayer increased surface resistance to oxidation. 

Dmbach, P. Matrix-assisted laser desorption-ionization mass spectrometry An overview. Spectroscopy 1998, 13, 16-27. 

The molecular weights and molecular weight distributions (MWD) of phenolic oligomers have been evaluated using gel permeation chromatography (GPC),23,24 NMR spectroscopy,25 vapor pressure osmometry (VPO),26 intrinsic viscosity,27 and more recently matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).28... 

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. 

Considering these situations, the observation of molecular weights, particularly by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MASS), is essential [33]. The operation is simple and enables us to observe the molecular ion peaks of CPOs with molecular weights exceeding 10,000. The quahty of the measurement is strongly dependent on the choice of the matrix. Therefore, the search for the best matrix for each CPO should be pursued. 

Wang, Z. Russon, L. Li, L. Roser, D. C. Long, S. R. Investigation of spectral reproducibility in direct analysis of bacteria proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy. Rapid Comm. Mass Spectrom. 1998,12,456-464. 

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