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1.
The polarographic behaviour of salicylaldehyde-2-pyridylhydrazone (SAPH) has been studied in aqueous buffer solution containing 40% ethanol using DC and DP polarographic methods. In the pH range 1.8–7.5 the observed single irreversible reduction wave is assigned to the splitting of the N-N bond and reduction of C=N centre. In alkaline medium, a second wave appears at a more negative potential due to the reduction of the salicylaldehyde which is formed by hydrolytic decomposition of the SAPH molecule. The effect of pH on the limiting current andE
1/2 as well as the reduction mechanism are discussed and compared with similar compounds. The kinetic parameters of the electrode reaction have been calculated.The analytical properties of the copper(II)-SAPH system is described. The complex gave rise to a single irreversible well-defined wave (E
1/2=–0.58 V at pH=5.2). The reaction process is diffusion controlled. A method is suggested for the determination of Cu(II) in presence of different metal ions as the difference in theirE
1/2 values is sufficient for the purpose.This work is taken partly from the M. Sc. Thesis of Jamal S. Shalabi 相似文献
2.
M. S. El-Shahawi A. Z. Abu Zuhri S. M. Al-Daheri 《Fresenius' Journal of Analytical Chemistry》1994,350(12):674-677
A simple and convenient extractive spectrophotometric method for the determination of ruthenium has been developed. It is based on the oxidation of the different ruthenium (II, III or IV) species to perruthenate with potassium periodate at pH 7.8. The perruthenate is then extracted with benzyltributylammonium chloride in chloroform followed by direct spectrophotometric measurements at 342 and 380 nm. The optimum concentration range was found to be 0.1–5 mg l–1, the standard deviation ±2.1%. The method has been successfully applied to the determination of ruthenium in organoruthenium compounds. 相似文献
3.
The redox behaviour of adsorbed species of 2,4,6-tri(2-pyridyl)-1,3-5-triazine (TPTZ) at the surface of a mercury electrode was examined using cycling voltammetry. Based on the adsorption and accumulation of TPTZ at the charged mercury surface cathodic adsorptive stripping voltammetry (CSV) is applied for the trace determination of TPTZ using a differential pulse (DP) technique. Experimental and operational parameters for the quantitative analysis of TPTZ are optimized and the detection limit was found to be 3×10–9 mol/l. The effect of some interferences, e.g. organic compounds, cations and anions, are investigated. 相似文献
4.
The complexes of the reagent 5-Br-PADAP with the metal ions La(III), Ce(III), and Y(III) have been studied.The composition and stability of these complexes have been determined. A sensitive spectrophotometric procedure for the determination of the metal ions La(III), Ce(III), and Y(III) has been proposed. The limitations of this procedure and the effect of other ions have been studied. 相似文献
5.
A review with 159 references is presented on the applications of adsorptive stripping voltammetry (AdSV) for determining
trace metal ions in different environmental samples (e.g. water, soil, plant, biological fluids). The analytical applications
of AdSV to biologically active organic compounds (e.g. pharmaceuticals, pesticides, biomolecules) are also discussed.
Received: 18 December 1995/Revised: 8 January 1997/Accepted: 12 January 1997 相似文献
6.
Ali Z. Abu Zuhri 《Monatshefte für Chemie / Chemical Monthly》1987,118(6-7):749-757
The polarographic behaviour of 1,3-bis[(2-pyridyl)methyleneamino]thiourea (PMAT) in solutions of varyingpH has been studied both in the absence and presence of Triton X-100 (T.X-100). The mechanism for the reduction process is discussed. The adsorption effect of electrochemically inactive T.X-100 on the polarographic waves ofPMAT has been investigated. The values of the kinetic parameters for the electrode reaction at differentpH values have been computed. The applicability of the polarographic method for determination ofPMAT is also discussed.
Das polarographische Verhalten von 1,3-Bis[(2-pyridyl)methylenamino]-thioharnstoff (PMAT) in Anwesenheit und Abwesenheit von Triton X-100. Die polarographische Bestimmung vonPMAT
Zusammenfassung Es wurde das polarographische Verhalten vonPMAT in Lösungen mit verschiedenempH sowohl in Gegenwart als auch ohne Triton X-100 (T.X-100) untersucht. Es wird ein Mechanismus für den Reduktionsprozeß diskutiert. Der Adsorptionseffekt des elektrochemisch inaktiven T.X-100 wurde hinsichtlich der polarographischen Wellen vonPMAT untersucht. Die kinetischen Parameter der Elektrodenreaktion wurden für verschiedenepH-Werte ermittelt. Ebenso wird die Anwendbarkeit der polarographischen Methode für die Bestimmung vonPMAT diskutiert.相似文献
7.
R. M. Shubietah A. Z. Abu Zuhri A. G. Fogg 《Fresenius' Journal of Analytical Chemistry》1994,348(11):754-757
Guanine is determined at the 5.0×10–10 –2.0×10–7 mol/l level by differential-pulse adsorptive stripping voltammetry at a hanging mercury drop electrode using the reduction peak of its copper (II) complex at –0.21 V vs. Ag-AgCl electrode. The optimum analytical conditions were found to be Britton-Robinson buffer solution (pH 4.8), an accumulation potential of 0.0 V and an accumulation time of 3 min. Under these conditions, the detection limit is 5.0×10–10 mol/l and the relative standard deviation 2.6% for 1.0×10–7 mol/l guanine. The method is compared with the previous voltammetric methods. The presence of some purine derivatives does not interfere. 相似文献
8.
Dimenhydrinate exhibits a single adsorptive stripping peak at a hanging mercury drop electrode after accumulation at 0.0V vs Ag/AgCl electrode at pH 3.8 (acetate buffer). The addition of trace amounts of copper ions enhanced the dimenhydrinate peak and its height depends on the concentration of each dimenhydrinate and Cu2+. The adsorptive stripping response was evaluated with respect to accumulation time and potential, concentration dependence, electrolyte, the presence of other purines, surfactants and other metal ions, and some variables. The calibration graph for dimenhydrinate determination is linear over the range 2.0×10–8–2.0×10–7 M (pre-concentration for 60s). The correlation factor is found to be 0.985 and RSD is 3.2% at 1.0×10–7 M. Detection limit is 1.0×10–8 M after 5 min accumulation. The determination of dimenhydrinate in pharmaceutical formulations by the proposed method is also reported. 相似文献
9.
M. M. Kamal A. Z. Abu Zuhri M. M. Hannoun 《Fresenius' Journal of Analytical Chemistry》1992,344(6):275-278
Summary The differential pulse polarographic (DPP) and voltammetric (DPV) behaviour of di-2-pyridyl ketone benzoylhydrazone (DPKBH), has been investigated over a wide pH range (2.1–11.5). The effect of various operational parameters on the reduction current are discussed and the mechanism of the electrode reaction is also included. Both methods DPP and DPV are applied for the analytical determination of this reagent and the detection limits are found to be 1.24 mol/l and 0.86 mol/l, respectively. The DPP behaviour of DPKBH in the presence of Pb(II), Cd(II) and Cu(II) is studied and the behaviour of the Cu(II)-DPKBH complex is fully investigated. The voltammetric determination of Cu(II), based on the accumulation of its complex at the hanging mercury drop electrode, is described. Statistical analysis of the calibration curve data is included.On leave from Assuit University, Egypt 相似文献
10.
The polarographic behaviour of 3-(2-thiazolylazo)-2,6-diaminopyridine (2,6-TADAP) has been studied in aqueous buffer solutions and aqueous-ethanol mixtures of different pH's using DC and DP polarographic methods. The reduction of the azo linkage takes place via two electrons in both aqueous and aqueous-ethanol mixtures. The linear relationship between the current and 2,6-TADAP concentration allowed the polarographic determination of 2,6-TADAP over a wide concentration range. The values of the adsorption parameters in the presence of both Triton X-100 (non-ionic) and a new non-ionic surfactant, nonylphenol polyoxypropylene polyoxyethylene (NPE 1800) have been computed. The kinetic parameters of the electrode reaction have been calculated.On leave from An-Najah National University, Nablus, West Bank, Via Israel. 相似文献