Iodometric microdetermination of some insoluble salts of silver,lead and mercury(II)

Summary An indirect iodometric method has been developed for the determination of AgCl, AgBr, AgI, PbCl₂, PbBr₂, PbI₂, PbSO₄ and HgI₂. The method does not require a prior dissolution of the sample. It is based on the exchange reaction between the insoluble salt and hydrogen sulphide, which yields a strong acid corresponding to the anion of the salt and in amount equivalent to the cation. The liberated acid is determined iodometrically. The method is simple, rapid and accurate.

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Zusammenfassung Eine indirekte jodometrische Methode zur Bestimmung von AgCl, AgBr, AgJ, PbCl₂, PbBr₂, PbJ₂, PbSO₄ und HgJ₂ wurde ausgearbeitet. Die Probe muß dazu nicht gelöst werden. Die Bestimmung beruht auf der Austauschreaktion zwischen dem unlöslichen Salz und Schwefelwasserstoff, die zur Freisetzung der dem Anion entsprechenden starken Säure in äquivalenter Menge führt. Diese wird jodometrisch titriert.

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In memoriam Professor Cecil L. Wilson.     

Synthesis and characterization of tin(IV) antimonate and study of its ion-exchange equilibria

Tin(IV) antimonate with different Sb/Sn molar ratios has been prepared. The characterization of the product materials was carried out using X-ray diffraction pattern, themal analysis and infrared spectra. The saturation capacities of sodium and cesium were found to increase with Sb/Sn molar ratios. TheK _d values on thermal treatment of tin(IV) antimonate, as a cation exchanger, have been measured for some heavy metal ions in the temperature range of 50–400 °C. The maximum adsorption of 10^–4M of the metal ions studied was obtained at 400 °C. The selectivity sequence was Eu³⁺>Co²⁺>Sr²⁺>Cs⁺ for the sample heated up to 400 °C. No adsorption was observed on the sample heated at 700 °C because of the formation of SnO₂ and Sb₆O₁₃.     

Recovery and determination of palladium from its alloys using iminodiacetic polyurethane/carbon nanofibers sorbent

New sorbent was synthesized by coupling iminodiacetic polyurethane foam with carbon nanofibers to increase its surface area and sorption capacity. FTIR, UV/Vis, Raman spectroscopy, elemental analysis, and scanning electron microscopy were used to characterize the IDAPUF/CNFs sorbent. By using these techniques, it was found that the sorbent contains 0.58, 0.62, and 2.23 mmol g^?1 of amino, carboxylic, and phenolic groups, respectively. The maximum sorption (99–100%) of palladium(II) ions onto IDAPUF/CNFs was achieved within 10–15 min at pH 5.0. A perfect isotherm curve with a zero intercept (0.0003) and good correlation (R² = 1) was obtained. The capacity of the IDAPUF/CNFs sorbent preloaded onto a glass column was calculated to be 0.58 mmol g^?1. The values of LOD, LOQ, and RSD% (n = 6) are 0.004 ng mL^?1, 0.013 ng mL^?1, and 1.17%, respectively. The accuracy of the procedure was verified by the recovery of Pd(II) ions (100%) from some palladium alloys and road dust samples (RSD% = 0.36).     

Modification of AOAC method 973.31 for determination of nitrite in cured meats

A modification of AOAC Method 973.31 is proposed to improve the extraction efficiency of nitrite from cured meat samples and its subsequent quantification based on the diazotization-coupling reaction of sulfanilamide with N-(1-naphthyl)ethylenediamine dihydrochloride (NED). The various experimental parameters were thoroughly investigated. A 5 g meat sample was mixed with 400 mL water; the pH of the mixture was adjusted to 5.5 +/- 0.3 and allowed to stand for 2 h on a water bath at 80 degrees C, with occasional shaking for the complete extraction of nitrite. After quantitative filtration, an aliquot was mixed with chloroacetic-chloroacetate buffer, pH 1.80 +/- 0.05, sulfanilamide, and NED, and the absorbance of the resulting azodye was recorded at 540 nm against water as a reference. Following the recommended procedure, a linear calibration graph was obtained for up to 0.8 microg/mL NO2(-), with a correlation coefficient of 0.9996 and a detection limit (based on the 3 Sb-criterion) of 5.6 ng/mL NO2(-). The proposed method was conveniently applied to various cured meat samples and was validated by comparison with the original AOAC method and by recovery experiments that gave quantitative results (94-98%) with convenient reproducibility. Statistical analysis of the analytical data could not detect any systematic error and revealed the high accuracy and precision of the proposed method.     

Damping in the Interaction of a Field and Two Three-Level Atoms Through Quantized Caldirola–Kanai Hamiltonian

We investigate the damped interaction between two Λ-type three-level atoms and a quantized single-mode cavity field, for which the Hamiltonian of the field is rewritten in Caldirola–Kanai form. We obtain the wave functions for the case where the two atoms are initially prepared in arbitrary pure states and the field is initially prepared in the coherent state. We investigate numerically the influence of the damping parameter on the temporal behavior of the Mandel Q-parameter, linear entropy, and normal squeezing. We find the damping parameter and initial atomic states to play central roles in the nonclassical features and the degree of entanglement.     

Magneto-thermo-elastic problem of a rotating nonhomogeneous anisotropic solid cylinder

In the present paper, we investigate the generation of thermal stresses in a nonhomogeneous anisotropic solid cylinder rotating about the z-axis at a constant angular velocity in the presence of a magnetic field. The governing equations are solved numerically using the boundary-element method (BEM) and numerical results are obtained for the variation of the temperature, displacements, and stresses along x-axis. The effect of nonhomogeneity is investigated.     

Generating Multi-hops Entangled Network Via Spin Dipolar Interaction

International Journal of Theoretical Physics - The possibility of generating a multi-hops network between different entangled nodes (qubits) via spin Dipolar interaction is examined. The...     

Some studies of the interaction between two two-level atoms and SU(1,1) quantum systems

Herein, we present an approach to look for the best phenomenon to measure quantum correlation. The system of two isolated qubits each interacting with a single-mode cavity was theoretically created to study the quantum correlation. Some of the phenomena, such as the quantum discord and concurrence, were generated through such a system. The influences of initial state purity, qubit motion, and detuning parameters were discussed for the phenomena. These parameters for a specific value show that the behavior of phenomena are analogous. It is interesting to mention that some values of detuning undergo a sudden death of phenomena, and the quantum discord still captures the qubits quantum correlation. We predict that the quantum discord may be a better measure of quantum correlation than concurrence.     

Antimicrobial activity of PVC-pyrazolone-silver nanocomposites

Poly(vinyl chloride)-pyrazolone; PVC-pz as a new modified form of PVC with high antibacterial and antifungal activities towards some Gram +ve bacteria S. Aureus, B. Subtilis and S. Faecalis) and Gram –ve bacteria (E. Coli, P. Aeruginosa and N. Gonorrhoeae) beside Candida albicans in addition to Aspragillus flavus as fungi has been synthesized in absence and in presence of silver-nanoparticles, AgNPs, in 3 and 5% by weight with respect to PVC. This was developed by a chemical reaction of PVC 1, and pyrazolone 2 in tetrahydrofuran, THF as solvent. PVC-pz derivative has been characterized by FTIR, ¹HNMR spectroscopic analyses, in addition to scanning and transmission electronic microscopy. Photostability of PVC-pz was evaluated by following the discoloration for UV- irradiated samples colorimetrically in accordance with degradation time. IR and ¹H-NMR analyses confirm that PVC-pz, 4 was formed indicating a substitution reaction of chlorine atoms of PVC chains to the hydrogen atom of active methylene and that attached to pyrazolone nitrogen at the same time. Antimicrobial activities of PVC-pz increased in the presence of AgNPs and with increasing its percentage.     

Septonex-tetraphenylborate screen-printed ion selective electrode for the potentiometric determination of Septonex in pharmaceutical preparations

A screen-printed electrode (SPE) was fabricated for the determination of 1-(ethoxycarbonyl)pentadecyltrimethylammonium bromide (Septonex) based on the use of Septonex-tetraphenylborate as the electroactive substance, and o-nitrophenyloctylether (o-NPOE) as the plasticizing agent. The electrode passes a near-Nernstian cationic slope of 59.33 ± 0.85 mV from activity between pH values of 2 to 9 with a lower detection limit of 9×10(-7) M and response time of about 5 s and exhibits an adequate shelf-life of 6 months. The method was applied for the determination of Septonex in pharmaceutical preparations. A percentage recovery of 99.88% was obtained with RSD=1.24%. The electrode was successfully applied in the determination of Septonex in laboratory-prepared samples by direct potentiometric, calibration curve and standard addition methods. Potentiometric titration of Septonex with sodium tetraphenylborate and phosphotungstic acid as a titrant was monitored with the modified screen-printed electrode as an end-point indicator electrode. Selectivity coefficients for Septonex relative to a number of potential interfering substances were determined. The sensor was highly selective for Septonex over a large number of compounds. Selectivity coefficient data for some common ions show negligible interference; however, cetyltrimethylammonium bromide and iodide ions interfere significantly. The analytical usefulness of the proposed electrode was evaluated by its application in the determination of Septonex in laboratory-prepared pharmaceutical samples with satisfactory results. The results obtained with the fabricated sensor are comparable with those obtained by the British Pharmacopeia method.