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81.
Rik Van Deun Peter Nockemann Tatjana N. Parac-Vogt Kristof Van Hecke Luc Van Meervelt Christiane Grller-Walrand Koen Binnemans 《Polyhedron》2007,26(18):5441-5447
The near-infrared luminescence properties of three (E)-N-hexadecyl-N′,N′-dimethylamino-stilbazolium tetrakis(1-phenyl-3-methyl-4-benzoyl-5-pyrazolonato) lanthanide(III) complexes are described. These three complexes, containing trivalent neodymium, erbium and ytterbium, respectively, show near-infrared luminescence in acetonitrile solution upon UV irradiation. Luminescence decay times have been measured. The complexes consist of a positively charged hemicyanine chromophore with a long alkyl chain and a tetrakis(pyrazolonato) lanthanide(III) anion. Because of the absence of an -hydrogen atom in the pyrazolonato ligands, and because of the saturation of the coordination sphere by four bidentate ligands, the luminescence properties are enhanced when compared to, e.g. quinolinate complexes. 相似文献
82.
P. A. Biondi Francesca Manca A. Negri Anna Berrini Tatjana Simonic C. Secchi 《Chromatographia》1988,25(7):659-662
Summary The activity of bacterial collagenase Clostridiopeptidase A was estimated using a labelled synthetic peptide, 4-phenylazobenzyloxycarbonyl-L-Pro-L-Leu-Gly-L-Pro-D-Arg,
as substrate. The N-protected dipeptide obtained after enzymatic hydrolysis of Leu-Gly peptide bond was quantified by reversed-phase,
high-performance liquid chromatography using 4-phenylazobenzyloxycarbonyl-L-Pro-L-Phe as internal standard. The time dependence
of the appearance of the hydrolysis product and the dependence of rates of hydrolysis on collagenase concentration were linear.
Kinetic parameters for collagenase were determined to test the suitability of the described procedure. 相似文献
83.
Rasheed Rashed Taleb Mansoor Hadeel S. Abdullah Thamer Adnan Juzsakova Tatjana Al-Jammal Noor Salman Ali Dawood Al-Shaikhly Rasha R. Le Phuoc Cuog Domokos Endre Abdulla Thaer A. 《Journal of Thermal Analysis and Calorimetry》2021,145(2):297-307
Journal of Thermal Analysis and Calorimetry - This paper deals with an advanced colorimetric method used to determine the catalase mimetic activity of V2O5 nanoparticles by measuring the decrease... 相似文献
84.
Continuous-flow and static dialysis coupled on-line to liquid chromatography was evaluated and an automated method for determination of ciprofloxacin in biological samples developed. A trace enrichment column packed with C18 material and coupled with a continuous dialysis and reversed-phase HPLC system with fluorescence detection enabled determination of ciprofloxacin in human blood serum at the 0.1-nmol/l level. The amount of analyte preconcentrated and loaded on the HPLC system was linearly proportional to the concentration in the dialysed sample over more than 4 orders of magnitude (up to 1 x 10(-6) M). Data for linearity, repeatability and detectability for each particular set-up are given. The trace enrichment step eliminates band broadening caused by solvents different from those of the eluent and affecting retention of ciprofloxacin on the analytical column (increase in k') due to the on-column change of eluent composition. In analysis of human serum samples phthalates leached from plastic materials may interfere due to coelution with the analyte. 相似文献
85.
An artificial neural network (ANN) model for the prediction of retention times in high-performance liquid chromatography (HPLC) was developed and optimized. A three-layer feed-forward ANN has been used to model retention behavior of nine phenols as a function of mobile phase composition (methanol-acetic acid mobile phase). The number of hidden layer nodes, number of iteration steps and the number of experimental data points used for training set were optimized. By using a relatively small amount of experimental data (25 experimental data points in the training set), a very accurate prediction of the retention (percentage normalized differences between the predicted and the experimental data less than 0.6%) was obtained. It was shown that the prediction ability of ANN model linearly decreased with the reduction of number of experiments for the training data set. The results obtained demonstrate that ANN offers a straightforward way for retention modeling in isocratic HPLC separation of a complex mixture of compounds widely different in pKa and log Kow values. 相似文献
86.
Dr. Volker Gatterdam Dr. Radhan Ramadass Dr. Tatjana Stoess Manuela A. H. Fichte Prof. Dr. Josef Wachtveitl Prof. Dr. Alexander Heckel Prof. Dr. Robert Tampé 《Angewandte Chemie (International ed. in English)》2014,53(22):5680-5684
Spatial and temporal control over chemical and biological processes plays a key role in life and material sciences. Here we synthesized a two‐photon‐activatable glutathione (GSH) to trigger the interaction with glutathione S‐transferase (GST) by light at superior spatiotemporal resolution. The compound shows fast and well‐confined photoconversion into the bioactive GSH, which is free to interact with GST‐tagged proteins. The GSH/GST interaction can be phototriggered, changing its affinity over several orders of magnitude into the nanomolar range. Multiplexed three‐dimensional (3D) protein networks are simultaneously generated in situ through two‐photon fs‐pulsed laser‐scanning excitation. The two‐photon activation facilitates the three‐dimensional assembly of protein structures in real time at hitherto unseen resolution in time and space, thus opening up new applications far beyond the presented examples. 相似文献
87.
Different capillary electrophoretic techniques were investigated and compared for the separation of low-molecular-mass phenolic
and neutral lignin degradation compounds. Simple capillary zone electrophoresis (CZE) was not suited for this problem. Switching
to micellar electrokinetic capillary chromatography (MEKC) by adding micelle-forming reagents to the carrier electrolyte enhanced
the separation performance considerably. Alternatively, microemulsion electrokinetic chromatography (MEEKC) was investigated.
This is a CE technique in which analytes interact with moving oil droplets present in a microemulsion buffer. Using the optimized
carrier electrolyte systems and a 60 cm×50 μm I.D. bubble cell capillary it was possible to analyse solutions of different
wood digestion procedures and to investigate differences in lignin degradation products during use of different kinds of wood
(eucalyptus, beech, scotch pine and acacia).
Received August 25, 1999. Revision April 13, 2000 相似文献
88.
Novel cationic polyelectrolytes with a brush-on-brush structure of poly(ethylene oxide) (PEO) side chains and a charge-containing polyacrylate backbone were synthesized. The PEO side chains were not directly attached to the backbone but via polymethacrylate spacers, thus locating the PEO chains a distance away from the charged units of the backbone. The cationic brush-on-brush polyelectrolytes with high density of PEO chains showed a strong affinity to silica surfaces, provided the backbone charge density was high enough. The adsorption of these polymers was studied by QCM-D giving very high sensed mass, 20 mg/m2. It was shown by direct force measurements that protective surface layers were formed by the novel polyelectrolytes, generating strongly repulsive steric forces, which provided an effective barrier against flocculation. The adsorbed layer was sufficiently robust to withstand sliding experiments under a pressure of up to 35 MPa. The friction force in water was very low, and the lubrication was characterized by a friction coefficient in the range of 0.02-0.06. 相似文献
89.
Peter Nockemann Dr. Michael Pellens Kristof Van Hecke Dr. Luc Van Meervelt Prof. Dr. Johan Wouters Prof. Dr. Ben Thijs Dr. Evert Vanecht Tatjana N. Parac‐Vogt Prof. Dr. Hasan Mehdi Stijn Schaltin Jan Fransaer Prof. Dr. Stefan Zahn Barbara Kirchner Prof. Dr. Koen Binnemans Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(6):1849-1858
A series of nitrile‐functionalized ionic liquids were found to exhibit temperature‐dependent miscibility (thermomorphism) with the lower alcohols. Their coordinating abilities toward cobalt(II) ions were investigated through the dissolution process of cobalt(II) bis(trifluoromethylsulfonyl)imide and were found to depend on the donor abilities of the nitrile group. The crystal structures of the cobalt(II) solvates [Co(C1C1CNPyr)2(Tf2N)4] and [Co(C1C2CNPyr)6][Tf2N]8, which were isolated from ionic‐liquid solutions, gave an insight into the coordination chemistry of functionalized ionic liquids. Smooth layers of cobalt metal could be obtained by electrodeposition of the cobalt‐containing ionic liquids. 相似文献
90.
Tatjana M. Trtić‐Petrović Ksenija R. Kumrić Jelena S. Đorđević Goran T. Vladisavljević 《Journal of separation science》2010,33(13):2002-2009
Transport behaviour of Lu(III) across a polypropylene hollow fibre‐supported liquid membrane containing di(2‐ethylhexyl)phosphoric acid (DEHPA) in dihexyl ether as a carrier has been studied. The donor phase was LuCl3 in the buffer solution consisting of 0.2 M sodium acetate at pH 2.5–5.0. A miniaturised system with a single hollow fibre has been operated in a batch mode. The concentration of Lu(III) was determined by indirect voltammetric method using Zn–EDTA complex. The effect of pH and volume of the donor phase, DEHPA concentration in the organic (liquid membrane) phase, the time of extraction and the content of the acceptor phase on the Lu(III) extraction and stripping behaviour was investigated. The results were discussed in terms of the pertraction and removal efficiency, the memory effect and the mean flux of Lu(III). The optimal conditions for the removal of 177Lu(III) from labelled 177Lu‐radiopharmaceuticals were discussed and identified. The removal efficiency of Lu(III) greater than 99% was achieved at pH of the donor phase between 3.5 and 5.0 using DEHPA concentration in the organic phase of 0.47 M and the ratio of the donor to the acceptor phase of 182. 相似文献