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排序方式: 共有66条查询结果,搜索用时 656 毫秒
31.
Madhusudanan KP Banerjee S Khanuja SP Chattopadhyay SK 《Biomedical chromatography : BMC》2008,22(6):596-600
The applicability of a new mass spectrometric technique, DART (direct analysis in real time) has been studied in the analysis of the hairy root culture of Rauvolfia serpentina. The intact hairy roots were analyzed by holding them in the gap between the DART source and the mass spectrometer for measurements. Two nitrogen-containing compounds, vomilenine and reserpine, were characterized from the analysis of the hairy roots almost instantaneously. The confirmation of the structures of the identified compounds was made through their accurate molecular formula determinations. This is the first report of the application of DART technique for the characterization of compounds that are expressed in the hairy root cultures of Rauvolfia serpentina. Moreover, this also constitutes the first report of expression of reserpine in the hairy root culture of Rauvolfia serpentina. 相似文献
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33.
K. P. Madhusudanan S. Durani R. S. Kapil D. Fraisse 《Journal of mass spectrometry : JMS》1990,25(5):265-270
Under ammonia chemical ionization (CI) conditions triarylpropenones undergo hydrogen radical-induced olefinic bond reduction on metal surfaces, resulting in [M + 2H + NH4]+ ions corresponding to the ammonium adduct of the saturated ketone. The decomposition of the adduct ions, [MNH4]+ and [M + 2H + NH4]+, was studied by collision-induced dissociation mass-analysed ion kinetic energy (CID-MIKE) spectroscopy in a reverse geometry instrument. From the CID-MIKE spectra of the [MNH4]+, [M + 2H + NH4]+, [MND4]+ and [M + 2D + ND4]+ ions it is clear that the fragmentation of the adduct ions involves loss of NH3 followed by various cyclization reactions resulting in stable condensed ring systems. Elimination of ArH and ArCHO subsequent to the loss of NH3 and formation of aroyl ion are characteristic decomposition pathways of the [MNH4]+ ions, whereas elimination of ArCH3 and formation of [ArCH2]+ are characteristic of the [M + 2H + NH4]+ ions of these propenones. 相似文献
34.
Madhusudanan KP Kumar B Kanojiya S Agnihotri G Misra AK 《Journal of mass spectrometry : JMS》2006,41(10):1322-1333
The tandem mass spectra of the divalent metal ion (Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Ni2+, Co2+ and Zn2+) adducts of acetylated 1,2-trans-glycosyl sulfides, sulfoxides and sulfones were examined using low energy collision-induced dissociation on a Quattro II quadrupole tandem mass spectrometer. Abundant doubly charged ions, such as [3M + Met]2+ and [2M + Met]2+, were observed with alkaline earth metal chlorides. The other ions observed were [M + MetCl]+, [M + MetOAc]+, [M + MetO2SPh]+ and [2M + MetCl]+. The deprotonated metal adducts [M + Met-H]+ were seen only in the sulfones. The divalent metal ion adducts showed characteristic fragmentation pathways for the glycosyl sulfides, sulfoxides and sulfones, depending on the site of metal attachment. The doubly charged metal ion adducts dissociate to two singly charged ions, [M + MetOAc]+ and [M - OAc]+, in the sulfides and sulfoxides. In the sulfones, the adducts dissociate to [M + MetO2SPh]+ and [M - O2SPh]+. In contrast to the alkaline earth metals, which attach to the acetoxy functions, the transition metals attach to the sulfide and sulfoxide functions. The metal chloride adducts display characteristic fragmentation for the sulfides, sulfoxides and sulfones. The glucosyl, mannosyl and galactosyl sulfides, sulfoxides and sulfones could be differentiated on the basis of the stereochemically controlled MS/MS fragmentations of the metal chloride adducts. 相似文献
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36.
LC-ESI-MS analysis of taxoids from the bark of Taxus wallichiana 总被引:1,自引:0,他引:1
Madhusudanan KP Chattopadhyay SK Tripathi VK Sashidhara KV Kukreja AK Jain SP 《Biomedical chromatography : BMC》2002,16(5):343-355
LC-ESI-MS analysis was carried out for taxoid profiling of partially purified methanol extracts of the stem bark of Taxus wallichiana growing in different regions of the Himalayas (Kashmir, Himachal Pradesh, UP hills, Sikkim and Arunachal Pradesh). Cone voltage fragmentation of the protonated, ammonium or sodium cationized molecular species resulted in diagnostic fragment ions. Thus, information about the number and nature of substituents and the taxane skeleton (whether it is normal or rearranged) was readily available from the LC-ESI-MS spectra. The rearranged 11(15-->1)-abeo-taxanes showed a characteristic elimination of the hydroxyisopropyl along with an acetoxy group. The identification of the taxoids was achieved by comparison of the ESI mass spectra with those of the authentic taxoids available to us or by interpreting the ESI mass spectra. The results were also corroborated by MS/MS analysis of the partially purified extract injected directly into the ESI source. Paclitaxel, its analogues and their xylosides are present in samples from all the regions. An interesting observation is the detection of a large number of basic taxoids having nitrogen-containing side chains. 相似文献
37.
Madhusudanan Sreejith P. Balamoorthy Elamathy M. Suresh Kumar Manivasagam Thirugnasambandam G. Batabyal Sudip K. 《Journal of Solid State Electrochemistry》2022,26(11):2411-2421
Journal of Solid State Electrochemistry - Cu2Fe1-xBaxSnS4 (CFBTS) thin films have been fabricated by the low-cost successive ionic layer and adsorption reaction (SILAR) method. The bandgap energies... 相似文献
38.
Madhusudanan KP 《Journal of mass spectrometry : JMS》2006,41(8):1096-1104
Tandem mass spectra of ammonium adducts of monosaccharides gave characteristic fragmentation patterns involving elimination of NH3/H2O followed by multiple eliminations of H2O and cross ring cleavages. Tandem mass spectra were examined over a range of collision energies (1-20 eV) on a triple-quadrupole mass spectrometer. The breakdown behavior of the ammonium adducts revealed patterns that could differentiate diastereomers of monosaccharides. 相似文献
39.
M. Suresh Kumar Madhusudanan Sreejith P. Kanth Sidhanth C. Mohanta Kallol Batabyal Sudip K. 《Journal of Solid State Electrochemistry》2020,24(2):305-311
Journal of Solid State Electrochemistry - The quaternary Cu2BaSnS4 (CBTS) is a new class of compound-semiconducting material, recently, emerging as one of the promising materials in the field of... 相似文献
40.
The chemical ionization (CI) induced reactions in certain chlorine-containing aryl-substituted alkyl nitriles have been studied using different reagent gases including ND3 and CD4 and with the help of collisional activation spectra. A few fragmentations can be explained only on the basis of protonation of or electrophilic attachment to neutral products formed in the CI source. A detailed investigation of the unusual dehalogenation and dehydrohalogenation reactions occurring in some of these molecules has shown that radical-induced cyclization processes give rise to these ions. 相似文献