نشریه شیمی کاربردی روز
پیاپی 23 (تابستان 1391)

Controlled drug release is one of the most important methods to increase the therapeutic effects and decrease side effects of drug. In this research، three drugs (piperazine، 8-aminoquinoline، N-phenyl piperazine) were attached chemically to the p-styrene sulphonyl chloride (as monomer)، and they were polymerized by AIBN (Azobis isobutyro nitrile) at 80 °C. Finally، release ability of three polymer-drugs were tested in buffer solution with pH= 1. 3 at the temperature 37 °C. The GPC spectra of the polymers showed that polymerization of monomers containing drugs were carried out. The results established that، these polymeric systems are able to release drugs.

A simple، rapid and environmentally friendly method has been developed for the determination of cobalt ions in water samples by dispersive liquid–liquid microextraction based on the solidification of floating organic droplet (DLLME-SFO) coupled with flame atomic absorption spectrometry (FAAS). In this method، cobalt was complexed with 2-nitroso-1-naphthol and extracted into a small volume of 1-dodecanol، which is of low density، low toxicity and proper melting point near room temperature. Several variables that affect the extraction efficiencies، including pH، concentration of chelating agent، type and volume of the extraction solvent and dispersive solvent، extraction time and salt addition، were investigated and optimized. Under the optimized conditions، the limit of detection was 1. 6 µg L−1 with a preconcentration factor of 25 for 25 mL of sample. The proposed method has been successfully applied for the determination of cobalt in real water samples.

This article describes easy، fast and efficient method for the diazotization and azidation of different aromatic amines over p-TSOH hydrate، sodium nitrite and sodium azide under mild condition at room temperature. Various aryl amines possessing electron-withdrawing groups or electron-donating groups were converted into the corresponding aryl azides in 75-99% yields. The use of mild reaction conditions، avoiding the use of harmful acids and toxic solvents and short reaction time are advantages of this methodology. The selected catalyst is found to be highly efficient.

In this research work a simple and very fast antisolvent-induced encapsulation procedure was developed and applied for extraction and preconcentration of silver nanoparticles from diluted aqueous solutions. Organic solvent (1. 0 ml) was added to a solution of silver nanoparticles capped with starch (2. 0 ml) for formation of a homogeneous solution. To the mixture solution، suitable amount of ammonium sulfate (0. 30 g) was added and the solution was vigorous shaken until the salt was completely dissolved. Then 1. 0 ml of organic antisolvent was added، after which it was separated into two clear phases by centrifugation at 3000 rpm for 5 min. The influences of effective parameters such as salt (type and amount)، organic solvent، and its volume were studied and optimized.

In this contribution، ZnO nanoparticles and vanadium doped ZnO were synthesized by wet chemical and wet incipient method، respectively. ZnO nanoparticles were heated at 650 and 750°C for 3h in air and then characterized by X-ray diffraction (XRD)، scanning electron microscopy (SEM)، energy dispersive (EDX) analysis and photoluminescence (PL). The XRD patterns showed that the ZnO samples have a wurtzite structure (hexagonal phase) and vanadium doped is in V2O5 crystalline structure. Their structural characteristics and physical properties were investigated and compared. XRD and SEM data show that the size of nanoparticles increased from 24. 3 to 32. 6 nm when the annealing temperature was increased. Also، the results indicate that increasing the degree of crystalline improved the physical properties of the nanoparticles.

In this study the adsorption of Cu2+، Pb2+ and Cr3+ ions from aqueous solution using olive leaves ash were investigated. The equilibrium adsorption level was determined as a function of the solution pH، temperature، contact time and adsorbent doses. Adsorption isotherms of heavy metal ions on adsorbents were determined and correlated with common isotherm equations such as Langmuir، Freundlich and Tempkin models. These studies were showed that the Langmuir isotherm model was fitted well with adsorption data. Kinetic studies were carried out on various kinetic models such as pseudo-first order، pseudo-second order and intra particle diffusion model. The pseudo-second order kinetic model was fitted very well with experimental data. Base on thermodynamic studies، this process was both endothermic and spontaneous، enthalpy and entropy were negative.

Cerium (IV) triflate [Ce (OTf) 4] was employed as a catalyst for facile preparation of coumarin derivatives via the one-pot Pechmann condensation of phenol derivatives with a β-ketoester. Various phenol derivatives with β-ketoesters were utilized in the reaction. At all experiments، the desired products were synthesized successfully. The described novel synthesis method proposes several advantages of safety، mild condition، short reaction times، high yields، simplicity and easy workup compared to the traditional method of synthesis.

An improved method for the determination of Triton X-100 in water samples has been developed using dispersive liquid–liquid micro extraction (DLLME) prior to HPLC analysis. The volume of extraction solvent (CHCl3)، disperser solvent (acetone) and sample solution، pH، ionic strength، and extraction time were selected as interested variables in DLLME process. Firstly، a screening experiment، Taghochi two-level orthogonal array، was employed to identify the important factors. Then the elucidation and optimization relationship between the response and the important factors was investigated by response surface methodology (RSM). The central composite design as the most popular of the many classes of RSM designs was used. The optimum experimental conditions found from this statistical evaluation were included: sample volume: 10. 0 mL، volume of extraction solvent (chloroform): 137. 7 µL، volume of disperser solvent (acetone): 0. 6 mL، centrifugation time: 5. 0 min، pH: 6. 2 (natural pH)، 2. 5% (w/v) NaCl and extraction time: 6. 0 min. Under the optimum conditions، the preconcentration factor of 120 was achieved. Calibration graph was linear in the range of 0. 01-100. 0 mg L−1 with correlation coefficient of 0. 9961. The Limit of detection (LOD) of 3. 0 µg L-1 was obtained for Triton X-100 determination

Two sensitive and selective spectrophotometric methods are presented for the determination of trace amounts of nitrite and nitrate. It relies on the reaction of nitrite with sulfadimidine (SD) and cisapride (CP) in acidic medium to form diazonium ions، which are coupled with 8-hydroxyquinoline (HQ) in basic solutions to form the related azo dyes. Absorbances were measured at 507 nm for SD-HQ product and at 532 nm for CP-HQ product. The calibration curves were linear in the ranges of 0. 05-2. 5 and 0. 04-5. 0 mg L-1 for SD-HQ and CP-HQ systems، respectively. The relative standard deviations for the nitrite determination methods were obtained as 0. 3-0. 9% and 0. 1-0. 8% for SD-HQ system and CP-HQ system، respectively. Nitrate was also determined after using a cadmium-copper reducing column. Interferences of various foreign ions were tested and the methods were successfully applied to the determination of nitrite and nitrate in various water samples.