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1.
Veličković Jelena Đ. Andrić Deana Roglić Goran Tešic Živoslav Lj. Milojković-Opsenica Dušanka M. 《平面色谱法杂志一现代薄层色谱法》2004,17(4):255-260
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of fourteen 1-arylpiperazine derivatives has been studied by thin-layer chromatography on both silica... 相似文献
2.
L. Andrić H. Bissantz E. R. Solarte F. Linder 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1988,8(4):371-378
A new apparatus is described for the study of photofragment spectroscopy of molecular ions in a coaxial laser-ion beam configuration. Complementary to other developments in this field, the apparatus emphasizes the kinetic energy spectroscopy of the photofragments and is particularly designed to study direct photodissociation processes via repulsive potential curves. On the laser side, the experiment uses discrete lines in the visible and UV region (Ar+ laser, excimer laser). A detailed analysis of the experimental conditions is presented, in particular with respect to the attainable energy resolution in the photofragment spectra. The apparatus provides sufficiently intense ion beams (5–10 nA) with controlled energy resolution (ΔE = 100?500 meV) and angular collimation (ΔΘ = 5?10 mrad). The measured photofragment spectra of H 2 + in the visible and UV region are in full accordance with the predictions of the design analysis. 相似文献
3.
Dendrinou-Samara C Zaleski CM Evagorou A Kampf JW Pecoraro VL Kessissoglou DP 《Chemical communications (Cambridge, England)》2003,(21):2668-2669
Reaction of Mn(ClO4)2 with di-pyridyl ketone oxime, (2-py)2C=NOH, gives the novel cluster [Mn(II)4Mn(III)6Mn(IV)2(mu4-O)2(mu3-O)4(mu3-OH)4(mu3-OCH3)2(pko)12](OH)(ClO4)3 1. It is the only example of a 24-MC-8, and the first metallacrown with ring metal ions in three different oxidation states. Magnetic measurements show antiferromagnetic behavior. 相似文献
4.
This study compared 2 post-column derivatization (PCD) techniques for the determination of aflatoxins B1, B2, G1, and G2 (AFB1, AFB2, AFG1, and AFG2) by fluorescence detection after liquid chromatographic separation: ultraviolet (UV) irradiation (PCD(UV)) and electrochemical bromination (PCD(EC)). Photochemical fluorescence enhancement was obtained with 2 different commercially available systems (PCD(UV1) and PCD(UV2)). An electrochemical bromination apparatus was used for bromination. Analyses of naturally contaminated or spiked samples of corn, pistachio paste, peanut butter, fig paste, and animal feed showed that neither of the techniques resulted in derivatization-specific matrix interferences for any of the matrixes under study, even when extracts were not completely purified. The response ratios PCD(UV)/PCD(EC) for AFB1, AFB2, AFG1, and AFG2 were 0.86, 0.96, 0.70, and 0.96, respectively, for PCD(UV1) and 0.82, 0.95, 0.60, and 0.90, respectively, for PCD(UV2). The long-term use of the UV lamps (300 h for PCD(UV1) and 343 h for PCD(UV2)) in the photochemical detectors showed that these ratios remained stable throughout the time frame investigated. The relative standard deviation obtained for each of the devices during the in-house validation study ranged from 0.3 to 1.8% for PCD(UV1), from 0.8 to 1.3% for PCD(UV2), and from 0.9 to 2.0% for PCD(EC). 相似文献
5.
Žarko P. Barbarić Stojadin M. Manojlović Boban P. Bondžulić Milenko S. Andrić Srđan T. Mitrović 《Optik》2014
New relationship of displacement signal using opposite sectors on a quadrant photodiode is derived. Standard and new displacement signals are analyzed in details. Through MATLAB® laser tracking simulation models, based on common and suggested approaches, detailed analysis is performed, and it is shown that better results for the new relationship signal processing are obtained. Within new relationship of displacement signal, the sensitivity of the system to the displacement of the spot increases and, hence, provides better accuracy in positioning up to 30%. 相似文献
6.
A study of crystal structures from the Cambridge Structural Database (CSD) and DFT calculations reveals that parallel pyridine–pyridine and benzene–pyridine interactions at large horizontal displacements (offsets) can be important, similar to parallel benzene–benzene interactions. In the crystal structures from the CSD preferred parallel pyridine–pyridine interactions were observed at a large horizontal displacement (4.0–6.0 Å) and not at an offset of 1.5 Å with the lowest calculated energy. The calculated interaction energies for pyridine–pyridine and benzene–pyridine dimers at a large offset (4.5 Å) are about 2.2 and 2.1 kcal mol?1, respectively. Substantial attraction at large offset values is a consequence of the balance between repulsion and dispersion. That is, dispersion at large offsets is reduced, however, repulsion is also reduced at large offsets, resulting in attractive interactions. 相似文献
7.
Aleksandra Radoičić Radivoj Petronijević Filip Andrić Živoslav Tešić 《液相色谱法及相关技术杂志》2017,40(5-6):297-303
ABSTRACTA new method for the extraction and quantitative determination of amygdalin has been proposed. Accelerated solvent extraction was applied for the extraction, and reversed-phase high-performance thin-layer chromatography method was developed, validated, and applied for the determination of amygdalin in the extracts of apricot, plum, almond, and peach kernels. The chromatographic system used was RP-18 silica, as stationary phase and acetonitrile/water (50:50, v/v), as mobile phase. Densitometric scanning was performed at 210 nm. The method was validated with respect to specificity, linearity, precision, and accuracy. The results showed that the peak area responses were linear within the concentration range of 2.5–50.0 µg/spot (R2 = 0.9984). The limit of quantification was 4.28 µg/spot, and the detection limit 1.28 µg/spot. The intra-day and inter-day reproducibility, in terms of %RSD, were in the range of 0.81–1.15 and 1.32–1.89, respectively. The accuracy data were in the range from 99.98 to 100.56%. The method is linear, quantitative and reproducible, and could be used as an efficient and economical green chromatographic procedure for the determination of amygdalin in the fruit kernel. 相似文献
8.
D. Živković N. Štrbac M. Sokić V. Andrić I. Jovanović M. Jovičić B. Andjelić S. Radosavljević 《Journal of Thermal Analysis and Calorimetry》2014,118(2):1369-1373
Preliminary results of physicochemical investigation of some archaeometallurgical findings from Kmpije locality in vicinity of Bor (Serbia) are presented in this paper. Ancient samples of prehistoric origin were investigated using different instrumental analytic methods—chemical, differential thermal, X-ray diffraction, and energy dispersive X-ray fluorescence analysis. Obtained results indicate to the presence of ancient metallurgical activities, so locality Kmpije may be considered as an archaeometallurgical site, which should be investigated more in future for more precise details. 相似文献
9.
Hydrogen Bonding between Metal‐Ion Complexes and Noncoordinated Water: Electrostatic Potentials and Interaction Energies 下载免费PDF全文
Jelena M. Andrić Majda Z. Misini‐Ignjatović Dr. Jane S. Murray Prof. Peter Politzer Prof. Snežana D. Zarić 《Chemphyschem》2016,17(13):2035-2042
The hydrogen bonding of noncoordinated water molecules to each other and to water molecules that are coordinated to metal‐ion complexes has been investigated by means of a search of the Cambridge Structural Database (CSD) and through quantum chemical calculations. Tetrahedral and octahedral complexes that were both charged and neutral were studied. A general conclusion is that hydrogen bonds between noncoordinated water and coordinated water are much stronger than those between noncoordinated waters, whereas hydrogen bonds of water molecule in tetrahedral complexes are stronger than in octahedral complexes. We examined the possibility of correlating the computed interaction energies with the most positive electrostatic potentials on the interacting hydrogen atoms prior to interaction and obtained very good correlation. This study illustrates the fact that electrostatic potentials computed for ground‐state molecules, prior to interaction, can provide considerable insight into the interactions. 相似文献
10.
Alkynyl ruthenium colorimetric sensors: optimizing the selectivity toward fluoride anion 总被引:1,自引:0,他引:1
Fillaut JL Andriès J Perruchon J Desvergne JP Toupet L Fadel L Zouchoune B Saillard JY 《Inorganic chemistry》2007,46(15):5922-5932
We report on the synthesis of alkynyl ruthenium colorimetric sensors whose receptors are constituted by thiazolidinedione, rhodanine, or barbituric heads as recognition centers for anions. As modifications in the charge density at these recognition centers affect the whole molecule, through the alkynyl ligand acting as a communicating wire, the effects of hydrogen-bonding interactions with the anions were observed with the naked eye and monitored by UV-vis absorption spectrometry. The selectivity of the sensors was improved through electronic modifications of the alkynyl ruthenium subunit: the higher the electron density at the receptor head, the higher the selectivity is. TD-DFT calculations rationalize the long-range electronic communication as a main characteristic of the alkynyl ruthenium species and as a key to improve the selectivity of alkynyl ruthenium-based sensors toward anions. 相似文献