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91.
This paper describes the development of screen-printed (SPE) and carbon paste (CPE) sensors for the rapid and sensitive quantification of naphazoline hydrochloride (NPZ) in pharmaceutical formulations. This work compares the electroactivity of conventional carbon paste and screen-printed carbon paste electrodes towards potentiometric titration of NPZ. The repeatability and accuracy of measurements performed in the analysis of these pharmaceutical matrices using new screen printed sensors were evaluated. The influence of the electrode composition, conditioning time of the electrode and pH of the test solution, on the electrode performance were investigated. The drug electrode showed Nernstain responses in the concentration range from 1 × 10(-6) to 1 × 10(-2) mol L(-1) with slopes of 57.5 ± 1.3 and 55.9 ± 1.6 mV per decade for SPE and CPE, respectively, and was found to be very precise and usable within the pH range 3-8. These sensors exhibited a fast response time (about 3 s for both SPE and CPE, respectively), a low detection limit (3.5 × 10(-6) and 1.5 × 10(-6) M for SPE and CPE, respectively), a long lifetime (3 and 2 months for SPE and CPE, respectively) and good stability. The selectivity of the electrode toward a large number of inorganic cations, sugars and amino acids was tested. It was applied to potentiometric determination of NPZ in pure state and pharmaceutical preparation under batch conditions. The percentage recovery values for the assay of NPZ in tablets (relative standard deviations ≤0.3% for n = 4) were compared well with those obtained by the official method. 相似文献
92.
Hanan F. Abd El-Halim F. A. Nour El-Dien Gehad G. Mohamed Nehad A. Mohamed 《Journal of Thermal Analysis and Calorimetry》2013,111(1):173-181
New seven metal complexes of tioconazole drug with the general formulae [MCl2(L)2(H2O)x].yH2O (where, x = 0 and y = 1 for M = Mn(II) or x = 2, y = 2 for M = Co(II)), and x = 0, y = 3 for M = Cu(II), Ni(II), Zn(II)) and [MCl2(L)2(H2O)2]Cl.3H2O (where M = Cr(III) and Fe(III)) have been prepared and characterized based on elemental analyses, IR, magnetic moment, molar conductance, and thermal analyses techniques. From molar conductance data bivalent metal chelates are non-electrolytes while Cr(III) and Fe(III) chelates are electrolytes and of 1:1 type. According to the IR spectral data, TCNZ is coordinated to the metal ions in a neutral unidentate manner with N donor site of the imidazole–N. All the complexes are octahedral except Mn(II) complex has tetrahedral structure. TCNZ drug and its metal complexes were also screened for their biological activity. 相似文献
93.
Nijem N Kong L Zhao Y Wu H Li J Langreth DC Chabal YJ 《Journal of the American Chemical Society》2011,133(13):4782-4784
The role of low binding energy sites on the adsorption of H(2) in metal-organic frameworks (MOFs) with unsaturated metal centers has not been identified. For instance, the importance of the benzene sites on H(2) adsorption at the metal site in MOF-74 has not been established. We report here experimental evidence that unambiguously shows that the internal mode of H(2) adsorbed at the metal site undergoes both a frequency shift and a marked change in its dynamic dipole moment when H(2) is adsorbed at the next nearest neighbor "benzene" site in MOF-74-Co. The effect of loading (i.e., occupation of all benzene sites) also induces spectroscopic shifts in H(2) at the metal site. These interactions highlight the role of lower binding energy sites in H(2) adsorption. 相似文献
94.
A. Anakkar A. Daoudi J. -M. Buisine N. Isaert F. Bougrioua H. T. Nguyen 《Liquid crystals》1996,20(4):411-415
High pressure studies for the n = 12 homologues of the 3-fluoro-4((R) or (S)-methylheptyloxy)-4'-(4-alkyloxy-3-fluorobenzoyloxy) tolanes series have been performed by thermobarometric analysis. The phase sequence presents two Twist Grain Boundary phases denoted TGBA and TGBC. The pressure-temperature phase diagram has been determined; it exhibits a SC* phase, and an induced phase identified as SA which does not exist under atmospheric pressure. The TGBA temperature stability domain versus pressure first increases, then rises to a maximum and finally disappears. Such phase behaviour leads to an experimental observation of two multicritical points SC*-SA-TGBA and SA-TGBA-N* for the pure compound under high pressures. This result confirms the existence of singular points previously predicted by the Renn-Lubensky theory. 相似文献
95.
We investigate some aspects of a generalized JC-model which include arbitrary forms of non-linearities of both the field and
the intensity-dependent atom-field coupling. We obtain an exactly analytic solution of the model, by means of which we identify
and numerically demonstrate the region of parameters where significantly large entanglement can be obtained. 相似文献
96.
Co-O and O-O bond stretching frequencies have been determined by oxygen isotopic substitution in a series of cobalt(III)—salen complexes. These all are of the binuclear type [Co(salen)L]2O2, with L being a basic ligand occupying an axial coordination position. The nature of the oxygen binding and the influence of the axial ligands are discussed. 相似文献
97.
Nour?ZidanEmail authorView authors OrcID profile 《International Journal of Theoretical Physics》2016,55(2):1274-1284
The dynamics of a mixed spin system governed by XXZ model in additional to an intrinsic decoherence is investigated. The behavior of quantum correlation and the degree of entanglement between the two subsystems is quantified by using measurement-induced disturbance and the negativity, respectively. It is shown that, the phenomena of long-lived entanglement appears for larger values of intrinsic decoherence parameters. The degree of entanglement and quantum correlation depend on the dimensions of subsystems which are pass through the external field and the initial states setting. We show that the negativity for some initial classes is more robust than the measurement-induced disturbance, while for some other initial classes the quantum correlations are more robust than entanglement. 相似文献
98.
In the event of a radioactive disaster, one of the biggest tasks is to estimate the radiation dosage received by people to
determine the actions of emergency response teams. The first and the most rapid screening method of internally contaminated
people in case of an emergency response is to perform in-vivo measurements for gamma-emitters. Development of virtual gamma-ray
calibration techniques will be critical for emergency invivo measurements because there are inadequate numbers of phantom
types to approximate all body shapes and sizes. The purpose of this project was to find a reliable way to estimate the efficiency
of gamma-systems using Monte Carlo computations, and to validate that efficiency by making measurements of a standard geometry.
Two geometries, a 5-ml ampoule and a Bottle Manikin Absorption (BOMAB) phantom head, spiked with 67Ga were used as standard geometries. The radioactive objects are measured at a number of distances from a high purity germanium
(HPGe) detector, and the experimental efficiency for our gamma-spectrometry system is determined. The same set of experiments
was then modeled using the Monte Carlo N-Particle Transport Code (MCNP). The conclusion of this project is that computationally
derived detector efficiency calibrations can be comparable to those derived experimentally from physical standards. 相似文献
99.
100.
Dissem Nour Kaur Prabhjyot Rana Love Karan Maris Thierry Duong Adam 《Transition Metal Chemistry》2021,46(4):283-290
Transition Metal Chemistry - One pot synthesis of a new mixed-ligand coordination polymer has been carried out by combining copper salt, macrocyclic ligand 1,4,8,11-tetraazacyclotetradecane... 相似文献