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61.
A novel sensitive and simple method for rapid and selective extraction, preconcentration and determination of uranyl as its 2,2′‐diamino‐4,4′‐bithiazole (DABTZ) complex by using octadecylsilica columns and spectrophotometry is presented. Extraction efficiency and the influence of flow rates of sample solution and eluent, pH, amount of DABTZ, type and least amount of eluent for elution of uranyl complex from columns, break‐through volume and limit of detection were evaluated. Also the effects of various cationic and anionic interferences on percent recovery of uranyl were studied. Average extraction efficiency of ca. 90% was obtained by elution of the column with minimal amount of solvent in the presence of interferences. The average preconcentration factor, 136 and a detection limit 0.32 ng·mL?1 were obtained. The method was applied to the recovery and determination of uranyl in different water samples. 相似文献
62.
Mir Azam Khan Zafar Iqbal Mohammad Rasul Jan Jasmin Shah Waqar Ahmad Zia Ul Haq Obaidullah 《Journal of Analytical Chemistry》2006,61(1):32-36
A simple spectrophotometric assay for the quantification of lactulose in pharmaceutical preparations was developed. The method
is based on hydrolysis of lactulose under acidic conditions. The hydrolyzed product reacts with resorcinol, giving absorption
peaks at 398 and 480 nm. Both absorption wavelengths can be used for the determination of lactulose. The limit of detection
of lactulose at 398 nm and 480 nm was 0.075 μg mL−1 and 0.65 μg mL−1, respectively. The calibration was linear in the range of 5–25 μg mL−1. Analytical conditions were optimized, and the method was validated for analysis of pharmaceutical preparations. The determined
amount of lactulose was found to be in good agreement with labeled claims in commercial products. The proposed method is economical,
convenient, and suitable for the quantification of lactulose in pharmaceutical preparations.
The text was submitted by the authors in English. 相似文献
63.
Gholam Hossein Rounaghi Mohammad Hossein Arbab Zavvar Azam Saremi 《Russian Journal of Inorganic Chemistry》2007,52(1):134-140
The complexation reactions between alkali and alkaline-earth metal cations with DB18C6 were studied in acetonitrile-methanol
(AN-MeOH) and tetrahydrofuran-threechloromethane (THF-CHCl3) binary mixtures at different temperatures using the conductometric method. The obtained results show that in most cases,
the DB18C6 forms 1:1 complexes with these metal cations and the stability of the complexes is affected by the nature and composition
of the mixed solvents. The stability order of complexes in AN-MeOH binary systems was found to be Na+ > Li+, and in the case of THF-CHCl3 binary mixtures was Na+ > Ba2+ > Li+. An anomalous and interesting behavior was observed for the case of complexation of a K+ ion with DB18C6 in the AN-MeOH binary
mixture and also for complexation of Mg2+ and Ca2+ cations with this ligand in pure THF and also in THF-CHCl3 binary systems. The values of the thermodynamic parameters (ΔH
c
o
and ΔS
c
o
) for complexation reactions obtained from the temperature dependence of the stability constants and the results show that
the complexes are both enthalpy-and entropy-stabilized.
The text was submitted by the authors in English. 相似文献
64.
Summary. Polyphosphazenes form one of the most important and interesting classes of inorganic polymers having a backbone of alternating
phosphorus and nitrogen atoms with phosphorus atom bearing two organic side groups. The most important feature of these polymers
is the synthesis route which allows the side groups to be changed over a wide range to obtain a broad variety of products
with different properties from elastomers to glasses, water soluble to hydrophobic polymers, bioinert to bioactive materials,
and electrical insulators to conductors. In this paper, some novel applications of these polymers in biomedical materials
and advanced devices are reviewed. 相似文献
65.
Kazi A. Azam Mohitosh Bhowmick Golam Mohammad Golzar Hossain Shariff E. Kabir Kalipada Kundu Khalifa Mohammad Abdul Malik Salina Perven 《Journal of chemical crystallography》2001,31(1):63-68
Treatment of [Ru3(CO)10(-dppm)] (1) with the ditelluride Te2(C6H4OEt-4)2 in refluxing toluene afforded the new aryltellurol bridged complex [Ru2(CO)4(-TeC6H4OEt-4)2 (-dppm)] (2) together with three known complexes [Ru4(CO)8(-CO)(4-Te)2(-dppm)] (3), [Ru2(CO)6{-CH2PPh(C6H4)PPh}] (4), and [Ru2(CO)6{-C6H4PPh(CH2)PPh}] (5). All the four complexes were characterized by spectroscopic methods, including an X-ray structure determination for 5. Complex 5 crystallizes in the monoclinic space group P21/c with a = 13.650(2), b = 9.995(2), c = 18.929(3) Å, = 97.49(2)°, V = 2560.4(8) Å3, and Z = 4. In this complex the two ruthenium atoms are bridged by the phosphino-phosphide ligand C6H4PPh(CH2)PPh which is attached to one Ru by the C6H4 group and a P atom while to the other Ru by both the two P atoms. Both the ruthenium atoms show distorted octahedral geometry. The Ru—Ru bond length is 2.8719(7) Å. 相似文献
66.
Akbar Azam Muhammad Arshad Ismat Beg 《Rendiconti del Circolo Matematico di Palermo》2008,57(3):433-441
We prove the existence of points of coincidence and common fixed points of a pair of self-mappings satisfying a generalized
contractive condition in cone metric spaces. Our results generalize several well-known recent and classical results.
相似文献
67.
The emission spectrum of SeO in the far ultraviolet first observed by Haranath (1) at low dispersion has been photographed in the region 2480-1930 Å under medium resolution and a reanalysis of the vibrational structure of the bands has been presented. Beginning at the longer wavelength end, the spectrum has been analyzed into five band systems which are designated as , x2-x1, y2-y1, , and . The lower state of the c-b system is found to be the upper state of the system observed recently by us (2). The derived constants in cm?1 for SeO are as follows (the constants of the b state are those derived from Ref. 2).
State | λ | |||
974 | 6.0 | |||
906 | 21.0 | |||
993 | 2.0 | |||
877 | 8.0 | |||
53080 | 954 | 13.0 | ||
51422 | 955 | 9.3 | ||
F1 | 51356 | 955 | 8.5 | ~36 |
50873 | 1034 | 9.3 | ||
9570.7 | 834.9 | 5.5 |