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131.
A systematic study for the optimization and implementation of high-performance capillary electrophoresis (HPCE) in conjunction with negative ion electrospray ionization-quadrupole time of flight-tandem mass spectrometry (ESI-QTOF-MS/MS) for the analysis of complex glycolipids is described. The performance of the capillary electrophoresis (CE) and off-line CE/ESI-QTOF-MS approach has been explored for screening a complex ganglioside mixture from bovine brain. All instrumental and solution parameters demonstrated to require special adjustment and to have the most substantial effect on the CE separation, abundance of product ions produced in a low-energy collision-induced dissociation (CID) process and their detection by MS/MS, when attempting to identify and sequence single ganglioside molecular species from CE eluted fractions. Upon optimization of the experimental parameters, an efficient methodology emerged providing the general basic requirements for combined CE/ESI-MS analysis of this type of complex glycoconjugate. 相似文献
132.
Radoslav D. Mii Radmila P. Marinkovi-Neduin Zoltán Schay István Nagy Jelena S. Kiurski Ern E. Kiss 《Reaction Kinetics and Catalysis Letters》2007,91(1):85-92
Investigations of a commercial NiMo/Al2O3 hydrodesulfurization (HDS) catalyst are directed towards optimization of the activation procedure of HDS catalyst concerning
active phase formation and thermal stability. Structural and textural data obtained with XRD, IR-FTIR, XPS and LTNA reveal
that the optimal temperature for the formation of active species on the catalyst surface and an appropriate pore structure
is 300°C. 相似文献
133.
Summary From studies of aqueous solutions of dodecylammoniumnitrate an association mechanism has been proposed involving multiequilibrium. In the concentration range considered we can differentiate between two aspects: ranges of marked qualitative and quantitative changes and formation of differently structured surfactant species.
Zusammenfassung Aus der Untersuchung wäßriger Lösungen von Dodecylammoniumnitrat würde ein Assoziationsmechanismus abgeleitet, welcher ein Multiequilibrium beinhaltet. Im untersuchten Konzentrationsbereich können zwei Bereiche unterschieden werden: Bereiche mit ausgeprägten qualitativen und quantitativen Änderungen und Bereiche mit der Bildung von verschieden strukturierten oberflächenaktiven Spezies.相似文献
134.
J. Brandštetr 《Journal of Thermal Analysis and Calorimetry》1981,21(2):357-365
A review of instruments for thermochemical (thermometric) solution analysis is given, including new types of isoperibol reaction of bomb calorimeters, the design of which can influence the future development of thermochemical measuring techniques. The new type of Dithermanal (Vaskut-EMG, Hungary, and Herrmann- Morris, France) controls the individual steps of the thermochemical analysis, adding memory and computing capabilities. Similar programming units with microprocessors for bomb and/or reaction calorimetry have been developed by Parr Comp. and Leco Comp. (USA). The latest modification of the Technicon flow analyzer permits on-line analysis of solid samples. For thermochemical titrations, the Sanda titrator (USA) and Vaskut automatic titrator (Hungary) are available. In the USA, the Tronac isothermal or isoperibol calorimeters are widely used. At the Technical University of Brno, ?SSR, smaller table instruments with a water-bath are applied for different modes of solution thermochemical analysis, and also for the reactions of solid samples in liquids. For the measurement of very small temperature differences, PTC thermistors are used. The possibilities of the future development of measuring techniques are outlined. 相似文献
135.
Zusammenfassung Die Temperaturabhängigkeit der Viskosität im System LiNO3–H2O und im Temperaturbereich 20–70°C wird in der Gleichung =A expB/T=T
0 zusammengefaßt; aus der so erhaltenen Beziehung werden Rückschlüsse auf die Struktur der Lösungen gezogen.
Temperature dependence of the viscosity in the system LiNO3–H2O is expressed by =A expB/T-T 0 in the temperature range 20–70°C. Possible relations to structural changes in the solutions are considered.相似文献
136.
Nataša Bukovec 《Thermochimica Acta》1985,96(2):391-395
The thermal decomposition of N2H5Nd(SO4)2·H2O has been studied by simultaneous TG and DSC and by isothermal weight change determination. The final product and the intermediate phases have been identified by chemical analysis, X-ray powder patterns and infrared spectroscopy. The solid phases in the decomposition sequence are: N2H5Nd(SO4)2· H2O → N2H5Nd(SO4)2 → NH4Nd(SO4)2 → Nd2(SO4)3. The reactions overlap under dynamicconditions, isothermally, however, NH4Nd(SO4)2 can be obtained by 200°C. 相似文献
137.
Summary Typical precipitation curves of various metal phosphates have been obtained using the turbidimetric technique. The following
systems have been investigated: Al(NO3)3-K3PO4, Al(NO3)3-KH2PO4, Al(NO3)3NaH2PO4, FeCl3-K3PO4, FeCl3-(NH4)2HPO4, FeCl3K2HPO4, FeCl3-KH2PO4, FeCl3-NaH2PO4, La(NO3)3K3PO4,La(NO3)3-K2HPO4,La(NO3)3-KH2PO4,La(NO3)3NaH2PO4 and Th(NO3)4-K2HPO4. Typical precipitation curves indicated concentration ranges of phosphate precipitation and of complex solubility.
Supported in part by the U.S. Army Research Office, Contract No. DA-ORD-10. 相似文献
Zusammenfassung Typische F?llungskurven verschiedener Metallphosphate, die mittels Trübungsmessungen erhalten wurden, wurden graphisch dargestellt. Die folgenden Systeme wurden untersucht: Al(NO3)3-K3PO4,Al(NO3)3KH2PO4, Al(NO3)3-NaH2PO4, FeCl3-K3PO4, FeCl3(NH4)2HPO4, FeCl3-K2HPO4, FeCl3-KH2PO4, FeCl3NaH2PO4, La(NO3)3-K3PO4, La(NO3)3-K2HPO4, La(NO3)3-KH2PO4, La(NO3)3-NaH2PO4 und Th(NO3)4K2HPO4. Typische F?llungskurven zeigten Konzentrationsgebiete, in welchen die Metallphosphate gef?llt werden, sowie Konzentrationen, die zur Komplexbildung führten.
Supported in part by the U.S. Army Research Office, Contract No. DA-ORD-10. 相似文献
138.
Unit cell parameters have been calculated from x-ray powder diffraction data of Mo2Br4
Py
4 (A), Mo2I4
Py
4 (B), Mo2I4
Pic
4 (C), Mo2(SCN)4
Py
4 (D) and Mo2(SCN)4
Pic
4 (E), A, B and C crystallize tetragonal. A witha=9,42,c=15,O2 Å; B witha=9,46,c=14,98 Å and C witha=9,66 andc=15,72 Å D and E crystallize orthorhombic. D witha=10,09,b=9,14,c=15,08 Å; E witha=10,22,b=9,41 andc=15,15 Å.Py=pyridine,Pic=4-methylpyridine. 相似文献
139.
A method for the determination of cadmium microamounts in mixtures with metallic ions withE
1/2 near toE
1/2 of cadmium is discussed. For higher selectivity cadmium was extracted in the form of the pyridin-thiocyanate complexes prior to polarography.
Bestimmung von Cadmium(II) neben anderen Metallionen
Zusammenfassung Es wird eine polarographische Methode zur Bestimmung von Cd(II) neben anderen Metallionen mitE 1/2 naheE 1/2(Cd) diskutiert. Zur Erhöhung der Selektivität und Genauigkeit wird eine Pyridin-Thiocyanat-Extraktion vorgeschalten.相似文献
140.
Graph theory is applied to the study of the dependence of total π-electron energy, π-electron charge distribution and free valency indices of conjugated hydrocarbons on molecular topology. It is shown that the number of loops in the molecular graph determines these quantities. 相似文献