MALDI-TOF 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. 

Matrix assisted laser desorption ionization-time of flight mass spectroscopy (MALDI-TOF MS) has proven to be a powerful tool for analysis of many biopolymers, such as proteins, oligonucleotides, and polysaccharides. Recently, it has been used to characterize many synthetic polymers [174]. Another... 

Kassalainen and Williams [135] coupled thermal field flow fractionation (ThFFF) and matrix-assisted laser desorption/ionisation time-of-flight mass spectroscopy (MALDI-ToF-MS) to yield a powerful combination of techniques for the analysis of polydisperse PS. ThFFF high selectivity and sensitivity to chemical composition were used to separate polydisperse polymers and polymer mixtures into the narrow polydispersity and homogeneous chemical composition fractions essential for MAT.DT-ToF-MS analyses. On the other hand, because it is possible to measure directly using MALDI-ToF-MS, it alleviates the need for polymer standards for ThFFF. Kassalainen and Williams [135] address the coupling of ThFFF and MALDI-ToF-MS and identify compatibility issues. Optimum conditions were determined and developed to maximise the capabilities of the combined technique. Depending on the polymer and the method of matrix-assisted laser desorption/ionisation (MALDI) sample deposition, fractions from 1-10 ThFFF runs were combined for MALDI-ToF-MS analysis. Binary solvents are used to enhance ThFFF retention and resolution of low (<15 kDa) polymers, and methods developed to allow routine MALDI-ToF-MS analyses of PS polymers up to 575 kDa. Overall, the compatibility of the two techniques was extended from several kilodaltons to several hundred kDa. Polymer... 

In this context, dialdehyde la (5 mg, 0.017 mmol), sarcosine (14 mg, 0.157 mmol) and five-fold excess of Ceo (60 mg, 0.083 mmol) dissolved in 10 ml of o-dichlorobenzene (o-DCB) heated at 130 °C for 90 min. After a typical work up procedure, the reaction mixture is purified by recycling HPLC on a preparative Buckyprep Cosmosil column (250 X 20 mm, toluene eluent, lOml/min flow rate) to furnish bis-fullerene derivative 3 in 32 % yield. The bis-fullerene 3 shows moderate solubility, thus allowed us to record and NMR spectra (Supp. Info., Fig. SI) corroborating the depicted structure in Scheme 1. The attenuated-total-reflectance infra-red (ATR-IR) spectrum of 3 demonstrates the characteristic stretching vibrations of the C-H (2803-3030cm" ) as well as the characteristic absorptions for fullerenes (Supp. Info., Fig. S2). Matrix-assisted-laser-desorption time-of-flight mass-spectroscopy (MALDI-TOF-MS), in the negative ionization mode and with the aid of trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile shows the molecu-... 

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... 

In recent years, the technology of mass spectroscopy has been well developed. The matrix-assisted Laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) can be applied to measure the molecular weights of macromolecules (up to one million Dalton) due to its high sensitivity and its wide response range. In combinatiOTi with the distribution of fragment lengths, it can be used to characterize those bio- and synthetic macromolecules with complicated molecular architectures. 

Matrix-assisted laser desorption/ionization—time-of-flight mass spectrometry MALDI-ToF MS is a variant of mass spectroscopy with the advantage of avoiding molecule fragmentation, especially with large organic molecules such as proteins. 

Zinc tetrakis(aryloxy)phthalocyanines such as 42 were shown to self-assemble into coordinating oligomers as demonstrated by UV-vis spectroscopy and mass spectrometry (MALDI-TOF) (Figure 29)P The compound was deposited onto carbon-coated grids and observed by TEM, which showed the formation of 50 nm diameter nanowires. As may be anticipated, similarly substituted free base and Ni(ll) phthalocyanines do not form aggregates. 

Sections are included on conventional synthesisers, microwave synthesisers, high-throughput FTIR spectroscopy, MALDI-TOF mass spectroscopy, scanning probe microscopy and nanoindentation, X-ray analysis and X-ray photoelectron spectroscopy, and thermal analysis. 

Based on the typical reactivity of the carboranyl group toward nucleophiles, dianionic disilox-anes and octaanionic silsesquioxanes were obtained by classical decapitation of the closo clusters via the reaction with KOH in ethanol at reflnx (Scheme 27.15). Products were fully characterized by FT-IR, H, "B, C, and Si NMR spectroscopy, MALDI-TOF mass spectrometry and the carbora-nyldisiloxane was also confirmed by x-ray diffraction analysis (Figure 27.18). 

The effects of the feed ratio in the lipase CA-catalyzed polymerization of adipic acid and 1,6-hexanediol were examined by using NMR and MALDI-TOF mass spectroscopies. NMR analysis showed that the hydroxyl terminated product was preferentially formed at the early stage of the polymerization in the stoichiometric substrates. As the reaction proceeded, the carboxyl-terminated product was mainly formed. Even in the use of an excess of the dicarboxylic acid monomer, the hydroxy-terminated polymer was predominantly formed at the early reaction stage, which is a specific polymerization behavior due to the unique enzyme catalysis. 

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