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1.
Influence of boric acid on the electrochemical deposition of Ni 总被引:1,自引:0,他引:1
M. Šupicová R. Rozik L. Trnková R. Oriňáková M. Gálová 《Journal of Solid State Electrochemistry》2006,10(2):61-68
The electrolytic deposition of Ni onto a paraffin-impregnated graphite electrode from supporting chloride electrolyte (0.5 mol dm−3 NaCl) adjusted to the required pH using dilute HCl is investigated. The effect of electrolyte composition on the Ni electrodeposition
is studied using linear sweep voltammetry in the cathodic region. An elimination voltammetry procedure was applied to evaluate
the polarization curves. The aim of this work was to deduce the mechanism of Ni reduction in the chloride bath as well as
the influence of boric acid on this. Positively-charged NiCl+ ions were found to be the electroactive particles in the Ni reduction mechanism. The strong competition between the NiCl+, Cl− and H+ ions for active sites at the electrode is discussed. Kinetically-controlled adsorption/desorption processes of various species
were also confirmed using elimination voltammetry with a linear scan. The evolution of gaseous hydrogen, catalyzed by the
freshly-deposited Ni, accompanies the electrodeposition process. The presence of boric acid at a sufficiently high concentration
inhibits the deposition of Ni and, at the same time, improves the morphology and brightness, as well as the adhesion of the
deposited Ni.
Elimination voltammetry with a linear scan is an efficient way to evaluate current–potential curves that reflect the electrodeposition
of one-component Ni coatings. By eliminating selected currents, additional interesting and useful information can be obtained
from voltammetric data. 相似文献
2.
Eldefrawi ME Azer NL Nath N Anis NA Bangalore MS O'Connell KP Schwartz RP Wright J 《Applied biochemistry and biotechnology》2000,87(1):25-35
An automated flow fluorometer designed for kinetic binding analysis was adapted to develop a solid-phase competitive fluoroimmunoassay
for urinalysis of opiates. The solid phase consisted of polymer beads coated with commercial monoclonal antibodies (MAbs)
raised against morphine. Fluorescein-conjugated morphine (FL-MOR) was used as the fluorescein-labeled hapten. The dissociation
equilibrium constant (K
D
) for the binding of FL-MOR to the anti-MOR MAb was 0.23 nM. The binding of FL-MOR to the anti-MOR MAb reached steady state within minutes and was displaced effectively by morphine
and other opiates. Morphine-3-glucuronide (M3G), the major urinary metabolite of heroin and morphine, competed effectively
with FL-MOR in a concentration-dependent manner for binding to the antimorphine MAb and was therefore used to construct the
calibration curve. The sensitivity of the assay was 0.2 ng/mL for M3G. The assay was effective at concentrations of M3G from
0.2 to 50 ng/mL, with an IC50 of 2 ng/mL. Other opiates and heroin metabolites that showed >50% crossreactivity when present at 1 μg/mL included codeine,
morphine-6-glucuronide, and oxycodone. Methadone showed very low crossreactivity (<5%), which is a benefit for testing in
patients being treated for opiate addictions. The high sensitivity of the assay and the relatively high cutoff value for positive
opiate tests allows very small sample volumes (e.g., in saliva or sweat) to be analyzed. A double-blind comparison using 205
clinical urine samples showed good agreement between this single-step competitive assay and a commercially performed enzyme
multiplied immunoassay technique for the detection of opiates and benzoylecgonine (a metabolite of cocaine). 相似文献
3.
A new C,O-cyclodialkylation of dilithiated cyclic beta-keto esters and beta-keto sulfones with 1,4-dibromo-2-butene is reported which results in regio- and diastereoselective formation of 2-vinyl-2,3,3a,4,5,6-hexahydro-2,3-benzofurans. The products could be efficiently transformed into functionalized bicyclo[3.2.1]octan-8-ones by a palladium-catalyzed rearrangement reaction. In case of sulfone derivatives, this rearrangement proceeds with high stereospecifity to give exclusively the endo-configured diastereomers. The bicyclo[3.2.1]octane skeleton is present in a large number of pharmacologically important natural products. 相似文献
4.
Nehad A. Abdallah 《Electroanalysis》2021,33(5):1283-1289
A novel electrode was fabricated for the quantitation of Fe2+ ion. It was based on the covalent attachment of the gemifloxacin molecule (the recognition element) to the surface of MWCNTs to be incorporated as an electroactive material. Linear response of Fe2+ ions was found in the concentration range of 1×10−2 mol L−1 to 1×10−8 mol L−1 with a Nernstian slope of 30.37 ±0.3 (mV/decade) and attained a stable response within 5 s. The sensor exhibited LOD value of 4.8×10−9 mol L−1. It was applied in the monitoring of Fe2+ concentration in multi-vitamins tablets, tap water and milk samples with acceptable recovery ranged from 94.00 % to 102.00 %. 相似文献
5.
R. Rozik R. Oriňàková K. Markušová L. Trnková 《Journal of Solid State Electrochemistry》2006,10(7):423-429
This paper describes a process of electrolytic deposition of nickel–cobalt (Ni–Co) binary alloy on Fe powder. Electrochemical behavior of this binary alloy was studied by cyclic voltammetry with a paraffin impregnated graphite electrode as a working electrode. Deposition of individual metals (Ni, Co), as well as the simultaneous nickel–cobalt co-deposition, was performed in aqueous solutions (Watts-type electrolyte) both with and without Fe powder. Special attention was paid to the influence of suspension density on the electrode process. This density affects on the quality of iron powder electroplating. Preferential deposition of the less noble metal (Co) leading to its higher content in the deposit was observed in contrast to the more noble one (Ni) in spite of higher content of Ni in the plating solution. This anomalous phenomenon–known already for other metals (Zn, Cd, Sn)–has been confirmed and investigated for iron-group metals (Fe, Co, Ni) in this work. Electrolytic deposition of Ni–Co binary alloys, including anomalous behavior is a complicated process. Understanding the anomalous behavior would lead to better control of the deposition process and to explanation of the mechanism of Ni–Co co-deposition. 相似文献
6.
Mohamed GG Nour El-Dien FA Khalil SM Mohamed NA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(5):1221-1226
Extraction spectrophotometric method has been developed for the determination of tricyclic drugs such as trazodone (TZH), amineptine (APH) and amitriptyline (ATPH) hydrochlorides in pure form and in the dosage forms coming from different Egyptian markets. The method based on the formation of ion-pairs between these drugs under investigation and inorganic complex of Mo(V)-thiocyanate followed by its extraction with methylene chloride. The optimum conditions for the ion-pairs formation are established. The method permits the determination of TZH, APH and ATPH over the concentration range of 2-28, 2-32 and 1-30 microg ml(-1), respectively. The Sandell sensitivity (S) is found to be 0.105, 0.138 and 0.118 g cm(-2) for TZH, APH and ATPH, respectively. The SD is found to be 0.16-0.377, 0.12-0.259 and 0.091-0.286 and the R.S.D. are 0.14-0.55, 0.12-0.399 and 0.095-0.485 for TZH, APH and ATPH, respectively. The method is applicable for the assay of the investigated drugs in different dosage forms and the results are in good agreement with those obtained by the official method. 相似文献
7.
Nour El-Dien FA Mohamed GG Mohamed NA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(1):20-26
A simple and rapid extraction spectrophotometric procedure has been developed for the determination of tricyclic anti-depressant drugs such as trazodone (TZH), amineptine (APH) and amitriptyline (ATPH) hydrochlorides in pure form and in different dosage forms. The method involves the formation of intense yellow ion-pairs between these drugs under investigation and methyl orange (MO) and bromocresol green (BCG) reagents followed by their extraction with 1,2-dichloroethane and quantitative microdetermination at 420 and 410 nm using MO or BCG, respectively. The optimum experimental conditions for the ion-pairs formation are established. The method permits the determination of TZH, APH and ATPH over a concentration range of 2-50, 2-50 and 1-25 microg ml(-1) for TZH, APH and ATPH, using MO and 1-25 microg ml(-1) for TZH, APH and ATPH, using BCG, respectively. The Sandell sensitivity (S) is found to be 0.106, 0.1071 and 0.0907 g cm(-2) for TZH, APH and ATPH, respectively, using MO reagent and 0.0788, 0.0661 and 0.0494 g cm(-2) for TZH, APH and ATPH, respectively, using BCG. The method is applicable for the assay of the investigated drugs in different dosage forms and the results are in good agreement with those obtained by the official method. 相似文献
8.
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
9.
Mohamed GG El-Dien FA Mohamed NA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,68(5):1244-1249
A simple and rapid spectrophotometric method has been developed for the determination of tricyclic anti-depressant drugs such as trazodone (TZH), amineptine (APH) and amitriptyline (ATPH) hydrochlorides in pure form and in different pharmaceutical preparations. The charge transfer (CT) reaction between TZH, APH and ATPH as electron donors and TCNQ as electron acceptor was utilized for their spectrophotometric determination. The optimum experimental conditions, like time, temperature, stoichiometry, solvents, for the CT complex formation are established. The method permits the determination of TZH, APH and ATPH over a concentration range of 10-400, 10-440 and 10-300 microg ml(-1), respectively. The sensitivity (S) is found to be 0.09, 0.087 and 0.069 g cm(-2) for TZH, APH and ATPH, respectively. The SD values are found to be 0.146-0.293, 0.154-0.285 and 0.091-0.212 and RSD values are 0.142-1.92, 0.297-1.92 and 0.212-0.915 for TZH, APH and ATPH, respectively. The low values of the relative standard deviation indicate the high accuracy and precision of the method. The mean recovery values obtained together with a high correlation coefficient values, amount in the range 98-101.5, 98.7-102.9 and 93-101.9 for TZH, APH and ATPH, respectively. The method is applicable for the assay of the investigated drugs in different dosage forms and the results are in good agreement with those obtained by the official method. 相似文献
10.
Sami Ul Haq Muhammad Atif Khan Nehad Ali Shah 《Chinese Journal of Physics (Taipei)》2018,56(1):261-269
The aim of this paper is to investigate the exact general solutions of the incompressible viscous fluid flow by using the time-fractional Caputo–Fabrizio derivative. The flow of the fluid is subject to the motion of a plane wall, embedded in a porous medium under the influence of magnetic field. The corresponding non-dimensional governing fractional differential equation with appropriate initial and boundary conditions is solved by means of integral transforms namely, Laplace and Fourier transforms. Solutions are expressed as a sum of steady and transient parts, for the sinusoidal oscillations of the plane wall. The influence of involved physical parameters are discussed graphically. Specifically, it has been observed that the effective permeability Keff reduces the time taken to reach the steady state. 相似文献