فهرست مطالب mohammadbagher gholivand

Corrosion control is an important parameter to supply safe drinking water considered by the World Health Organization. This study is intended to determine the scaling and corrosion potentials of drinking water in rural distribution networks during 2009-2017 in different climate zones of Kermanshah province, Iran. The most commonly used corrosion indices, Langelier saturation index (LSI), Ryznar stability index (RSI), Puckorius scaling index (PSI), aggressive index (AI), and Larson–Skold index (L-SI), were calculated. Statistical analysis was executed to examine the significant differences in water corrosion and scaling indices between different climate zones. Statistical analysis showed significant differences in water chemical characteristics related to corrosion and scaling potentials between different climate zones (except temperature). Statistical analysis also indicated significant differences in water corrosion and scaling indices (P <0.001) between different climate zones. The lowest average amounts of LSI (0.06), AI (12.13), and L-SI (0.06), and the highest values of RSI (7.44) and PSI (7.11) were observed in moderate humid climate zone. Also, the highest values for LSI (0.39), and L-SI (0.15) were related to warm semi-arid climate zone. Based on water characteristics in various climate zones, LSI and RSI were chosen as good indices for corrosion or scaling of water corrosion potential in different climate zones. The results indicated that there is a weak tendency towards corrosion for warm semi-dry climate zones in contrast to the other climate zones that have higher corrosion potentials for Kermanshah Province under the conditions of this study, or maybe related to local water quality characteristics among climate zones.

The electrochemical oxidation of an antidepressants drug, trazodon (TRZ) on the modified titanium dioxide–carboxylated multiwall carbon nanotube glassy carbon electrode (TiO2-cMWCNTs/GCE) was studied. The TiO2-cMWCNTs/GCE sensor was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The influence of the effective parameters on the electrochemical behavior of TRZ such as: pH, modifier volume, accumulation potential and time were optimized. Under the optimized conditions, the proposed sensor was applied to determine TRZ  in the ranges of 6–100 nM and 100-1000 nM with the detection limit of 5 nM using  differential pulse anodic stripping voltammetry (DPASV) at neutral pH. The modified electrode exhibited a good sensitivity, stability and pleasant reproducibility, which was also applied for the determination of TRZ in the spiked human serum and pharmaceutical formulations, with satisfactory results.

For the first time, an analytical methodology based ondifferential pulse voltammetry (DPV) at a glassy carbon electrode (GCE) assisted by two multivariate calibration (MVC) models including back propagation-artificial neural network (BP-ANN), non-linear class, and partial least squares-1 (PLS-1), classical class, thatthey have been constructed on the basis of non-bilinear first order differential pulse voltammetry (DPV) data,was developed and validated for the simultaneous determination of Ascorbic acid, Uric acid, Acetaminophen, and Noradrenalinto identify which approach offers the best predictions.The baselines of the DPV signals were corrected by asymmetric least square spline regression (AsLSSR) algorithm. Before applying the PLS-1,lack of bi-linearity was tackled by potential shift correction using correlation optimised warping (COW) algorithm. The multivariate calibration (MVC) model was developed as a quaternary calibration modelin a blank human serum sample (drug-free) provided by a healthy volunteer to regard the presence of a strong matrix effect which may be caused by the possible interferents present in the serum, and it was validated and tested with two independent sets of analytes mixtures in the blank and actual human serum samples, respectively.According to the obtained results, the PLS-1 was recommended for simultaneous determination of AA, UA, AC, and NA in both blank and actual human serum samples .

In this report, a glassy carbon electrode (GCE) modified with multi-walled carbon nanotube (MWCNT), ionic liquid (IL) and nickel oxide nanoparticles NiO NPs has been introduced for the simultaneous determination of clozapine (CLOZ) and sertraline (SER) as antipsychotic drugs in biological fluids and pharmaceutical formulation using differential pulse adsorptive stripping voltammetric (DPAdSV) technique. The MWCNT-IL/NiONPs modifier catalyzed the oxidation of both drugs and enhanced the sensitivity of the resulted electrode for CLOZ and SER monitoring. The response of the electrode to CLOZ and SER oxidation were linear over the concentration ranges of 0.5 – 67 µM and 0.21 – 85 µM (R2>0.99), respectively. The detection limits of 0.052 and 0.047 µM were obtained for CLOZ and SER, respectively. The proposed electrochemical sensor exhibited a high sensitivity, good selectivity, and was successfully used for simultaneous determination of CLOZ and SER in real samples.

A comparative study of ultrasound-assisted extraction (UAE) and hydro-distillation was performed for fast extraction of estragole from tarragon (Artemisia dracunculus L.) dried leaves. Several influential parameters of the UAE procedure in the extraction of estragole (type of solvent, extraction cycles, solvent to material ratio, irradiation time and particle size) were investigated and optimized. It was found that UAE offers a more rapid extraction of estragole than hydrodistillation. The optimum parameters were solvent to material ratio of 8:1 v/m, 96% (w/w) ethanol in water as extraction solvent, particle size of 1.18 mm, irradiation time of 5 min, output power of 63 W, 9 pulses, and ultrasonic frequency of 20 kHz. The recovery of estragole by UAE under optimal conditions was 44.4% based on dry extract. The benefit of ultrasound was to decrease the extraction time (5 min) relative to the classical hydrodistillation method (3 h). The experimental results also indicated that ultrasound-assisted extraction is a simple, rapid and effective method for extraction of the volatile oil components of tarragon.

A new method is presented, for the determination of copper, based on adsorptive stripping voltammetry of the complex of copper with minoxidil at a hanging mercury drop electrode (HMDE). The most suitable operating conditions and parameters, such as pH, accumulation potential, deposition time, ligand concentration and scan rate, were selected. The calibration graph for copper (II) was linear over the concentration range of 0.5 to 700 nM; the detection limit of the method was 0.09 nM. The interferences of some common ions were studied and the method was found suitable for determination of copper (II) in water anddrug samples. Moreover, by using of the proposed method, there is a considerable improvement in the detection limit, linear dynamic range and deposition time, compared to the methods other than adsorptive stripping voltammetry for the determination of copper.

The adsorptive behavior of the immunosuppressive agent tacrolimus was studied by cyclic and differential-pulse voltammetry on a hanging mercury drop electrode (HMDE). The drug was accumulated at HMDE and two well-defined peak currents were obtained at -1353 and -1417 mV vs. SCE (saturated KCl) in borate buffer (pH 10.0) + 0.1 KCl solution. A voltammetric procedure was developed for the determination of tacrolimus using differential-pulse adsorptive stripping voltammetry (DPAdSV). The optimum working conditions for determination of the drug were established. The analysis of tacrolimus in pharmaceutical dosage forms was carried out satisfactorily.