Electrospray mass spectrometry ESI-MS

Irganox 1076 [octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,6-di-t-butyl-4-methylphenol and diisooctyl phthalate were analyzed by GPC interfaced with both electrospray mass spectrometry (ESI-MS) and NMR.1 A deuterochloroform solvent was used. It was noted that a parallel arrangement was necessary to avoid backpressure on the NMR flow-probe that can... 

The prepared solutions were monitored by liquid chromatography coupled with a diode array detector (DAD) and with an electrospray mass spectrometry (ESI-MS) detector. Isolation of the formed pigments was achieved by HPLC at the semipreparative scale. 

In addition to H and NMR analysis, TLC coupled in an offline manner with electrospray mass spectrometry (ESI-MS) and high-resolution ESI Fourier transform ion cyclotron resonance (FTICR) MS for isolation and characterization of two novel lupane triterpenoids from Paullinia pinnata L. 6P-(3 -methoxy-4 -hydroxybenzoyl)-lup-20(29)-ene-one and 6P-(3 -methoxy-4 -hydroxybenzoyl)-lup-20(29)-ene-ol, which are suspected to play a crucial role in the plant s wound healing effects [32]. The extract from Paullinia pinnata L. was subjected to an exhaustive isolation procedure starting with two consecutive column chromatography purifications on silica gel different ratios of chloroform-methanol were used as eluent. The triterpenoid-containing fraction was purified on preparative silica gel TLC plate with chloroform-methanol (9 1, v/v) as a developing solvent. The two resulting lupane bands were finally submitted to MS analyses. 

Di Marco, V.B. and Bombi, G.G. (2006) Electrospray mass spectrometry (ESI-MS) in the study of metal-ligand solution equilibria. Mass Spectrom. Rev., 25,... 

In such strategies, two comonomers are intentionally defined as 0 and 1 bits. The monomer T is a thymine nucleotide, which is used to start the sequence and facilitates the pol rmer characterization, (b) Extended-ASCII encoded text that was implemented in the primary structure of a polymer using the monomer-based digital code, (c) Schematic representation of the primary structure of the corresponding sequence-coded polymer and its characterization by negative mode electrospray mass spectrometry (ESI-MS). 

In order to evaluate the performance of these dithioesters in HDA cycloadditions, poly (ethylene glycol) monomethyl ether (PEG) was equipped with an open-chain diene and, in another example, with a cyclopentadienyl endgroup in order for the HDA adducts to be clearly characterized by electrospray mass spectrometry (ESI-MS). The reaction schematic is presented in Figure 2.5a. 

Electrospray ionization mass spectrometry (ESI-MS) is an analytical method for mass determination of ionized molecules. It is a commonly used method for soft ionization of peptides and proteins in quadmpole, ion-trap, or time-of-flight mass spectrometers. The ionization is performed by application of a high voltage to a stream of liquid emitted from a capillaty. The highly charged droplets are shrunk and the resulting peptide or protein ions are sampled and separated by the mass spectrometer. 

Electrospray Ionization Mass Spectrometry (ESI-MS) Elimination Half-life Elimination of Drugs EM-800... 

Electrospray Ionization - Mass Spectrometry (ESI-MS). The Jacobsen s Co-salen catalysts dissolved in dichloromethane were pumped to the mass spectrometer system after dilution with methanol at a flow rate of 50 pi min and 600 scans were collected in 1 min. 

Schneiter, R. Brugger, B. Sandhoff, R. Zellnig, G. Leber, A. Lampl, M. Athenstaedt, K. Hrastnik, C. Eder, S. Daum, G. Paltauf, F. Wieland, F. T. Kohlwein, S. D. Electrospray ionization tandem mass spectrometry (ESI-MS/MS) analysis of the lipid molecular species composition of yeast subcellular membranes reveals acyl chain-based sorting/remodeling of distinct molecular species en route to the plasma membrane. J. Cell Biol. 1999,146,741-754. 

Synthetic linear dihydroxamic acids may be considered as models of rhodotorulic acid (3) to investigate steric effects on the formation of mono- or di-iron(III) species (127,128). pH-dependent electrospray ionization-mass spectrometry (ESI-MS) methods show that ferric complexes with dihydroxamates with short linker chains (37 and 38 in Fig. 15) will prefer the dimeric... 

In common with M. macedonicus, urine from male M. spretus also demonstrated a MUP-sized band following gel electrophoresis. The proteins within this band were analysed by high resolution anion exchange chromatography and electrospray ionisation mass spectrometry (ESI-MS). The former technique produced an elution profile consisting of just three peaks, in contrast to both the more complex patterns observed previously from M. m. domesticus and the single major peak in M. macedonicus. Furthermore, similar analyses from five individual males resulted in near... 

The ability to prepare monoliths within a mold of any shape was used by Lee et al. [128] who prepared monolithic ST-DVB microbeads within pulled fused silica needles and used them for the reversed-phase separation and on-line electrospray ionization mass spectrometry (ESI-MS) detection of proteins and peptides. As illustrated by Fig. 18, these monolithic microcolumns separated proteins far better than capillaries packed with commercial C18 silica or polymeric beads. 

Kamel AM, Zandi KS, Massefski WW. 2003. Identification of the degradation product of ezlopitant, a non-peptidic substance P antagonist receptor, by hydrogen deuterium exchange, electrospray ionization tandem mass spectrometry (ESI/MS/MM) and nuclear magnetic resonance (NMR) spectroscopy. J Pharm Biomed Anal 31 1211. 

Numerous workers have demonstrated the applicability of electrospray ionization mass spectrometry (ESI/MS) for the detection and analysis of biomolecules with highly electronegative groups (reviewed by Wood et al., 2003, and for neutral steroids by Higashi and Shimada, 2004). The sensitivity of detection of neurosteroids can also be enhanced by derivatization when they are analyzed by nano-electrospray/mass spectrometry procedures. Neurosteroid sulfates can be easily prepared in a single-step reaction in pyridine with the N,N-dimethylformamide complex of sulfur trioxide (Chatman et al., 1999). Another elegant... 

Pluym et al. compared the use of CE to that of HPLC in chemical and pharmaceutical quality control. They stated that CE could be considered as a complementary technique to HPLC because of its large separation capacity, its simplicity, and its economical benefits. Jimidar et al. decided that CE offers high separation efficiency and can be applied as an adjunct in HPLC method validation. Mol et al. evaluated the use of micellar electrokinetic chromatography (MEKC) coupled with electrospray ionization mass spectrometry (ESI—MS) in impurity profiling of drugs, which resulted in efficient separations. 

Electrospray ionization mass spectrometry (ESI-MS) is a powerful technique for analyzing non-covalent complexes formed between small molecules and proteins. 

Over the past decades several techniques have been used to obtain direct experimental information on the speciation of peroxo metal complexes heteronuclear NMR, IR and Raman spectroscopy, potentiometry and electrospray ionization mass spectrometry (ESI-MS). Often, more than one technique was used at the same time for acquiring complementary evidence. A significant, although nonexhaustive, list of examples related to several metals is given in Table 2. They include cases with hydrogen peroxide or alkyl... 

The capacity of inositol orthoformate derivatives 124 and 125 for binding to alkali metal ions was studied by electrospray ionization mass spectrometry (ESI-MS) gas-phase measurements <2001JOC8629>. The [5.5.5]-iono-phore 125 n = 3) possessed the highest Li /Na selectivity and the best affinity for Li. The results obtained proved to be in agreement with the size-fit concept. Other factors which influence the complexation are the orientation of the oxygen atoms, which are able to bind to metal, the basicity, and the polarizability of the heteroatoms around the perimeter of the binding cavity. 

Sarni-Manchado, P. and Cheynier, V., Study of noncovalent complexation between catechin derivatives and peptide by electrospray ionization-mass spectrometry (ESI-MS). J. Mass Spectrom. 37, 609, 2002. 

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