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991.
Polina Davletbaeva Marina FalkovaEvgenia Safonova Leonid MoskvinAndrey Bulatov 《Analytica chimica acta》2016
A novel stepwise injection fluorometric method for the determination of epinephrine in human urine has been developed. In the current study, the stepwise injection analysis (SWIA) was successfully combined with on-line in-syringe cloud point extraction (CPE) and fluorometric detection. The procedure was based on the epinephrine derivatization in the presence of o-phenylenediamine followed by the preconcentration stage based on the CPE with the nonionic surfactant Triton X-114. After the phase separation into a syringe of the flow system, the micellar phase containing the epinephrine derivative was transported to a fluorometric detector. The excitation and emission wavelengths were set at 447 nm and 550 nm, respectively. The conditions of epinephrine derivatization and CPE have been studied. The calibration plot constructed using the developed procedure was linear in the range of 1·10−11–5·10−7 mol L−1. The limit of detection, calculated as 3 σ of a blank test (n = 10), was found to be 3·10−12 mol L−1. The proposed method was successfully applied for the determination of epinephrine in human urine samples. 相似文献
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994.
Stepan A. Ukhanev Sergei V. Fedorov Leonid B. Krivdin 《Magnetic resonance in chemistry : MRC》2022,60(9):869-876
The substituent α-, β-, and γ-effects of the elements of the second and third periods on 19F NMR chemical shifts are evaluated including the establishment of stereochemical dependence of γ-effect, the latter particularly important in stereochemical studies of fluorine-containing compounds. Benchmark calculations performed for a series of 32 simple inorganic fluorine-containing molecules demonstrated a markedly good correlation between calculated and experimental fluorine chemical shifts characterized by a mean absolute error of 22.5 ppm in the range of about 900 ppm, which corresponds to a 2.5% error in the percentage terms. 相似文献
995.
Pilyak F. S. Kulikov A. G. Pisarevsky Yu. V. Blagov A. E. Kovalchuk M. V. 《Crystallography Reports》2022,67(5):791-798
Crystallography Reports - A diversity of effects leading to deformation of illuminated crystals has been mentioned. A methodical approach to studying the processes of generation of photoinduced... 相似文献
996.
Viktor I. Bogdan Aleksey E. Koklin Igor I. Mishanin Tatiana V. Bogdan Nikolay V. Mashchenko Leonid M. Kustov 《Mendeleev Communications》2021,31(2):230-232
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997.
M. A. Bryushinin V. V. Kulikov Yu. A. Kumzerov E. V. Mokrushina A. A. Petrov I. A. Sokolov 《Physics of the Solid State》2014,56(8):1644-1653
The non-steady-state photoelectromotive force effect was experimentally studied in a semiconductor nanowire array, i.e., in a composite representing selenium in a chrysotile asbestos matrix. The sample was exposed to an oscillating interference pattern, and the material response was measured as an alternating electric current. The experiments were performed for two geometries in which the excited photocurrent was parallel or perpendicular to nanowires. The dependences of the signal amplitude on the phase modulation frequency, spatial frequency, light polarization, and temperature were obtained. The photoelectric parameters of the material were determined for the light wavelength λ = 633 nm. The effect was theoretically analyzed for the semiconductor model with shallow traps, which allowed the explanation of the observed increase in the signal amplitude in the presence of additional phase modulation. 相似文献
998.
Mikhail Kamencev Nina Yakimova Leonid Moskvin Irina Kuchumova Kirill Tkach Yulia Malinina 《Electrophoresis》2016,37(22):3017-3019
Fast isotopic separation of 10B and 11B boric acid by CZE was demonstrated. The BGE contained 25 mM phenylalanine and 5 mM putrescine (рН 8.95). The running conditions were +25 kV at 20°C with indirect photometric detection at 210 nm. Baseline separation was achieved in less than 9 min. RSD of migration times and corrected peak areas were less than 0.5 and 3%, respectively (n = 5). Linearity was demonstrated in the range 0.2–2 mM for 11B and 0.2–0.5 mM for 10B. 相似文献
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