Narges Vaezi; Nasser Dalali; Mehdi Hosseini
Volume 4, Issue 1 , March 2017, , Pages 59-66
Abstract
A simple, novel, accurate and selective method for the determination of trace amounts of Cu2+ ions in water and soil samples is proposed. The method is based on the separation and preconcentration of Cu2+ on a nano-SiO2 modified by a cetyltrimethylammonium bromide as surfactant and indane-1,2,3-trione-1,2-dioxime ...
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A simple, novel, accurate and selective method for the determination of trace amounts of Cu2+ ions in water and soil samples is proposed. The method is based on the separation and preconcentration of Cu2+ on a nano-SiO2 modified by a cetyltrimethylammonium bromide as surfactant and indane-1,2,3-trione-1,2-dioxime as complexing agent. The retained copper on the nano-sorbent was eluted with 1.5 mL of 1.0 mol L-1 HNO3 and measured by flame atomic absorption spectrometry. The synthesis of this nano-sorbent is also described and certified by FTIR, XRD and TEM techniques. Furthermore, several effective analytical parameters were evaluated and optimized. Under the best optimum conditions maximum absorption capacity, enrichment factor and limit of detection were 7.04 mg g-1, 333.3 and 4.4 µg L-1, respectively. The relative standard deviation of the preconcentration method was 0.28% (n=7) and calibration curve gave good level of linearity with correlation coefficient value 0.997. Finally, the feasibility and performance of the method was evaluated by determination of copper (II) ions in several water and soil samples with satisfied results.
Ghobad Mansori; Mohammad_Bagher - Gholivand; Zarrin - Es'haghi
Abstract
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 ...
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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 .
Masoomeh Shaghaghi; Samaneh Rashtbari; Laleh Solouki; Somaieh Soltani; Gholamreza Dehghan
Abstract
Danofloxacin (DNF), a synthetic fluoroquinolone, is widely used as an antibacterial agent against a broad spectrum of pathogens. In the present study, the effects of DNF on the structure of bovine serum albumin (BSA) were investigated using UV-Vis absorption and fluorescence spectroscopy, and molecular ...
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Danofloxacin (DNF), a synthetic fluoroquinolone, is widely used as an antibacterial agent against a broad spectrum of pathogens. In the present study, the effects of DNF on the structure of bovine serum albumin (BSA) were investigated using UV-Vis absorption and fluorescence spectroscopy, and molecular docking methods at different temperatures. The obtained results of UV-Vis absorption studies showed that the microenvironment of the fluorophore residues does not significantly change upon interaction with DNF. Also, fluorometric studies revealed BSA-DNF complex formation and fluorescence quenching of BSA in the presence of DNF. The number of binding sites and binding constants were calculated to be ~1 and in the order of 103, respectively. According to thermodynamic parameters, van der Waals forces and hydrogen bonding play the main role in the BSA-DNF complex formation, which is a spontaneous process. The binding distance between DNF and BSA was calculated by the Förster resonance energy transfer (FRET) method. Molecular docking results were in agreement with thermodynamic and spectroscopic data and confirmed the binding mechanism of DNF to BSA.
Mehdi Taghdiri; Setareh Zakeri-Shahvari; Hamidreza Zare-mehrjardi
Abstract
The principle of this research is based on the development of multi-residue method by QuEChERS sample preparation follow by gas chromatography with mass spectrometric detection in the selected ion monitoring mode (GC–MS-SIM) for the routine analysis of 42 pesticides in rice samples. The rice samples ...
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The principle of this research is based on the development of multi-residue method by QuEChERS sample preparation follow by gas chromatography with mass spectrometric detection in the selected ion monitoring mode (GC–MS-SIM) for the routine analysis of 42 pesticides in rice samples. The rice samples were initially extracted with acetonitrile, and the targeted pesticides were purified following the dispersive solid phase extraction (d-SPE) cleanup method. The calibration curve for each analyte quantified by matrix-matched calibration was linear over the concentration range of 10.0–1000.0 μg L−1 with a correlation coefficient range between 0.990 and 0.999. Mean recoveries from three replicates ranged from 79% to 112%, with satisfactory precision (RSD<7%). The limit of detection and the limit of quantification were in the range of 3.04–12.52 μg L−1 and 10.14–41.76 μg L−1 respectively, for all 42 pesticides.
Reza Abedi; Aiyoub Parchehbaf Jadid; Zhila Azari
Abstract
In this study, a novel and efficient solid phase extraction method based on the use of γ-alumina (γ-Al2O3) nanoparticles coated with sodium dodecyl sulfate and modified with (E)N'-(2-hydroxy benzylidene) isonicotinohydrazide (H2L) as a new adsorbent was developed for separation and determination ...
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In this study, a novel and efficient solid phase extraction method based on the use of γ-alumina (γ-Al2O3) nanoparticles coated with sodium dodecyl sulfate and modified with (E)N'-(2-hydroxy benzylidene) isonicotinohydrazide (H2L) as a new adsorbent was developed for separation and determination of trace amounts of copper(II) prior to flame atomic absorption spectrometry (FAAS). The analyte ions were adsorbed quantitatively on adsorbent due to their complexation with (H2L). The separation procedure was studied with regard to experimental parameters such as pH, amount of sodium dodecyl sulfate , ligand’s concentration, contact time, type and volume of eluent and stirring rate. The effects of interfering ions on the extraction procedure were also investigated. Under the optimum experimental conditions, the extraction efficiency was 98, 97 and 95.5 with relative standard deviation lower than 5% for Shurabil Lake, the collected water behind the barrier and Baligluchai River, respectively. Noticeably, the method has been successfully applied for the extraction and determination of copper content in some real samples.
Farzaneh Shamsa; Alireza Motavalizadehkakhky; Rahele Zhiani; Jamshid Mehrzad; Malihe Sadat Hosseiny
Abstract
Microorganisms create metal nanoparticles (MNPs) after being exposed to toxic metal ions. Nevertheless, the catalytic performance of biosynthesized MNPs has not been investigated in spite of the possibility of utilizing these biological processes in the stable improvement of vital metals (e.g. zinc oxide). ...
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Microorganisms create metal nanoparticles (MNPs) after being exposed to toxic metal ions. Nevertheless, the catalytic performance of biosynthesized MNPs has not been investigated in spite of the possibility of utilizing these biological processes in the stable improvement of vital metals (e.g. zinc oxide). This strategy has excellent advantages like high economic efficiency and tolerance of functional groups. DaZnO NPs characteristics were recognized by numerous techniques, including FT-IR, SEM, TEM, XRD, and EDS analyses. In this study, biogenic zinc oxide nanoparticles were produced by the Desulfovibrio alaskensis to reduce carbon dioxide for the preparation of formate salts in an aqueous medium.
Masoomeh Shaghaghi; Gholamreza Dehghan; Fatemeh Khajevand
Abstract
Chelation therapy has been used to remove toxic metals from the body for a long time. Flavonoids such as quercetin (QUR), a well-known protective antioxidant and free radical scavenger, can bind to metal cations and protect our bodies from toxic metals. In the current study, we used UV–Vis, 1HNMR, ...
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Chelation therapy has been used to remove toxic metals from the body for a long time. Flavonoids such as quercetin (QUR), a well-known protective antioxidant and free radical scavenger, can bind to metal cations and protect our bodies from toxic metals. In the current study, we used UV–Vis, 1HNMR, IR, and fluorescence spectroscopic techniques as well as viscosity measurements to investigate the synthesis, characterization, and interaction between Bi(III)-QUR complex and calf thymus DNA (ctDNA) in physiological buffer. The antioxidant activity of the complex was assessed utilizing DPPH and ABTS free radical scavenging, and ferric reducing potential. After chelation of the Bi(III) cation, the antioxidant potential of QUR was reduced. In the presence of ctDNA, the absorption spectrum of Bi(III)-QUR complex was raised, and the fluorescence intensity of Bi(III)-QUR complex was increased. With the addition of the Bi(III)-QUR complex, the relative viscosity of ctDNA rose. These findings indicate that the Bi(III)-QUR complex interacts with ctDNA in a groove-binding mode. The thermodynamic parameters (ΔH, ΔS, and ΔG) of the Bi(III)-QUR complex with ctDNA, as well as well as association constant, Ka, and number of binding sites (n), were assessed from the fluorescence data, indicating that the binding of Bi(III)-QUR complex to ctDNA was primarily driven by hydrophobic interactions.
Pourya Abbasi; Keyvan Shayesteh; Vahid Vahidfard; Mehdi Hosseini
Abstract
Nickel is one of the metallic impurities that should be removed from the electrolyte solution before the electrowinning of zinc. This study investigated the parameters affecting the process of nickel removal in an Iranian zinc smelter plant by the response surface methodology. According to the results ...
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Nickel is one of the metallic impurities that should be removed from the electrolyte solution before the electrowinning of zinc. This study investigated the parameters affecting the process of nickel removal in an Iranian zinc smelter plant by the response surface methodology. According to the results of experiments, the optimum condition for removal of nickel was obtained at temperature of 85 °C, the residence time of 60 minutes, zinc powder of 2.5 g/l, mixing speed of 500 rpm, and pH of 5. With regards to the resulting model from the Design-Expert software, the significant parameters were concentration, residence time, and temperature, respectively.
Parvin Pourhakkak; Mohammad Ali Karimi; Hossein Tavallali; Pouran Pourhakkak; Mohammad Mazloum Ardakani
Abstract
A new potentiometric sensor based on a β- cyclodextrin modified carbon paste electrode (CPE) was designed for the determination of the captopril drug. The effect of various cyclodextrins (α, β and γ- cyclodextrins) and their percentage, binder agent and ion additive on the potential ...
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A new potentiometric sensor based on a β- cyclodextrin modified carbon paste electrode (CPE) was designed for the determination of the captopril drug. The effect of various cyclodextrins (α, β and γ- cyclodextrins) and their percentage, binder agent and ion additive on the potential response have been investigated and the electrode with the best potential response was found. The linear concentration range for this electrode was 7.0×10-7-1.0×10-1 M with a low detection limit of 2.0 × 10-7 M. The effect of pH and temperature on the Nernstian slope was also investigated and the optimal range was obtained. The selectivity of the captopril CPE to interfering species including Li+, K+, Ni+, Mg2+, Ca2+, Co2+, Cr2+, Cr3+, Zn2+,Mn2+, Fe2+, F-, Cl-, SO42-, C2O42- PO43-, C2O42-, ascorbic acid, uric acid, glucose, D-fructose and sucrose was determined by Separate Solution (SSM) and Matched Potential Method (MPM) methods. Finally, the proposed electrode was tested for measuring captopril in drug formulation, blood serum, and urine samples.
Robab Mohammadi; Bakhshali Massoumi; Amin Mashayekhi
Abstract
In this research, Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline nanocompounds were prepared and compared on the removal of methyl orange from aqueous solutions. The chemical structures of the synthesized compounds were studied using FT-IR. The crystalline phase of Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline ...
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In this research, Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline nanocompounds were prepared and compared on the removal of methyl orange from aqueous solutions. The chemical structures of the synthesized compounds were studied using FT-IR. The crystalline phase of Fe3O4, Fe3O4/polystyrene and Fe3O4/polyaniline nanocompounds was characterized by XRD. SEM was used for detecting morphology of the synthesized samples. The magnetic property of the prepared samples was successfully checked. The prepared nanocompounds were used to remove methyl orange as an anionic dye from aqueous solutions. Based on results, Fe3O4/polyaniline nanocomposite showed higher efficiency in the removal of methyl orange, which is partly due to the oppositely charged methyl orange and Fe3O4/polyaniline. Effective variables on the removal of methyl orange such as adsorbent dosage, pH, and contact time were studied and optimized. At the optimum situations the pH, catalyst dosage, and time were 3-4, 450 mg L-1, and 50 min, respectively. For detecting the type of adsorption isotherm, Langmuir, Freundlich, and Dubinin Radushkevich adsorption isotherms were studied. According to Langmuir model, Fe3O4/polyaniline magnetic absorbent showed the highest methyl orange adsorption capacity of 48.76 mg g−1. Kinetic studies proved that methyl orange adsorption was explained more accurately via pseudo-second order model compared to the pseudo-first order model. Under controlled reaction conditions, Gibbs free energy (ΔG˚) varied from -1.41 to -1.69 kJ mol-1, besides, the resulting ΔH˚ and ΔS˚ quantities were obtained 4.07 kJ mol-1 and 0.018 kJ mol-1K-1, respectively. Therefore, it can be considered that the adsorption of methyl orange onto the Fe3O4/polyaniline magnetic absorbent is a spontaneous and endothermic procedure.
Nasrin Soltani; Nahid Tavakkoli; Maryam Khayatkashani; Elham Eslami
Abstract
In this study, curcuma zedoaria extract was investigated as a mild steel (MS) corrosion inhibitor in 0.5 M H2SO4 solution by conventional methods of weight loss (WL), electrochemical impedance spectroscopy (EIS) and polarization at 25 °C. The highest percentage of inhibition was obtained for the ...
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In this study, curcuma zedoaria extract was investigated as a mild steel (MS) corrosion inhibitor in 0.5 M H2SO4 solution by conventional methods of weight loss (WL), electrochemical impedance spectroscopy (EIS) and polarization at 25 °C. The highest percentage of inhibition was obtained for the concentration of 0.5 g/l of curcuma zedoaria extract. The results of polarization method showed that curcuma zedoaria extract acts as a mixed inhibitor. Examination of MS immersion time by weight loss method showed that with increasing immersion time, the inhibitory effect decreases in low concentrations of curcuma zedoaria extract but in higher concentrations of curcuma zedoaria extract (concentration 1.0 g/L), the inhibitory effect remains almost constant over time. The effect of temperature on the performance of curcuma zedoaria extract by electrochemical polarization method in the temperature range of 35-65 °C shows a decrease in inhibition percentage with increasing temperature. Adsorption of curcuma zedoaria extract molecules on the surface of MS at all studied temperatures follows the Langmuir adsorption isotherm. Using the results of kinetic and thermodynamic calculations, the adsorption of molecules of curcuma zedoaria extract on the surface of MS physical adsorption type was observed.
Parisa Jamalipour; Nasrin Choobkar; Maryam Abrishamkar; Elham Pournamdari
Abstract
In this current article, a chemical sensor was synthesized PbS functionalized with Gelatin Quantum Dots for Fenpyroximate. The measure of Fenpyroximate was performed using concentration (2.5×10-3 mol L-1), PbS Quantum Dot-Gelatin nanocomposites sensor, pH 6, and time 40 s, wavelength 328 nm. Under ...
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In this current article, a chemical sensor was synthesized PbS functionalized with Gelatin Quantum Dots for Fenpyroximate. The measure of Fenpyroximate was performed using concentration (2.5×10-3 mol L-1), PbS Quantum Dot-Gelatin nanocomposites sensor, pH 6, and time 40 s, wavelength 328 nm. Under the optimum conditions, the detection limit linear range were obtained (0.02 to 20.0 µg L-1). The standard deviation of less than (2.0%), and detection limits (3S/m) of the method (0.02 µg L-1) for determination of Fenpyroximate, was obtained. The observed outcomes confirmed the suitability recovery and a very low detection limit for measuring the Fenpyroximate. The chemical PbS Quantum Dot–Gelatin nanocomposites sensor as excellent sensor in the practical application of Fenpyroximate related to residue management is in surface water samples.
Zahra Garkani Nejad; Abuozar Ghanbari
Abstract
Three-dimensional quantitative structure-activity relationship (3D-QSAR) techniques are useful methods for ligand-based drug design by correlating physicochemical descriptors from a set of related compounds to their known molecular activity or molecular property values. A novel clubbed triazolyl thiophene ...
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Three-dimensional quantitative structure-activity relationship (3D-QSAR) techniques are useful methods for ligand-based drug design by correlating physicochemical descriptors from a set of related compounds to their known molecular activity or molecular property values. A novel clubbed triazolyl thiophene series of cdk5/p25 inhibitors were selected to establish 3D-QSAR models using Comparative molecular field analysis (CoMFA) and Comparative molecular similarity indices analysis (CoMSIA) methods. The optimum CoMFA and CoMSIA models obtained, were statistically significant with cross-validated correlation coefficients r2cv (q2) of 0.539 and 0.558, and conventional correlation coefficients (r2) of 0.980 and 0.967, respectively. A training set containing 88 molecules and a test set containing 24 molecules served to establish the QSAR models. Independent test set validated the external predictive power of both models with predicted correlation coefficients (r2pred) 0.968 and 0.945 for CoMFA and CoMSIA, respectively. Molecular docking was applied to explore the binding mode between the ligand and the receptor. The information obtained from molecular modeling studies may be helpful to design novel CDK5/P25 inhibitors with desired activity.
Reyhaneh Rahnama; Atena Shabani Afroozi; Mohammad Reza Jamali
Abstract
In the present work, an efficient method was developed for the determination of lead in natural water samples. In this method, lead was extracted by octanoic acid reverse micelles (bulk phase) and measured by flame atomic absorption spectroscopy (FAAS). Ligand 1-(2-Pyridylazo)-2-naphthol was used as ...
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In the present work, an efficient method was developed for the determination of lead in natural water samples. In this method, lead was extracted by octanoic acid reverse micelles (bulk phase) and measured by flame atomic absorption spectroscopy (FAAS). Ligand 1-(2-Pyridylazo)-2-naphthol was used as a chelating agent. In order to obtain the best extraction results, some experimental parameters (such as pH, ligand concentration, ionic strength, etc.) affecting the extraction efficiency were investigated and optimized. Under optimal conditions, the calibration curve was linear in the concentration range of 2.5-200.0 μgL-1 with a correlation coefficient of 0.9998. The detection limit was 0.8 μgL-1 and the preconcentration factor was 50. This method was successfully used to measure lead in natural water samples.
Shahryar Pashaei; Samaneh Safari; Soleyman Hosseinzadeh
Abstract
In the present study, synthesis of silver nanoparticles and its antibacterial activity were investigated. Silver nanoparticles were rapidly synthesized using leaf extract of beet sugar leaf the formation of nanoparticles was observed within 1 hr. The results recorded from UV–vis spectrum, Transmission ...
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In the present study, synthesis of silver nanoparticles and its antibacterial activity were investigated. Silver nanoparticles were rapidly synthesized using leaf extract of beet sugar leaf the formation of nanoparticles was observed within 1 hr. The results recorded from UV–vis spectrum, Transmission electron microscopy (TEM) and X-ray diffraction (XRD) support the biosynthesis and characterization of silver nanoparticles. The UV-Visible spectrophotometer was indicated absorbance peak in range of 435-440 nm. From high resolution transmission electron microscopy (HRTEM) analysis, the size of the silver nanoparticles was measured 35–40nm. Further, the antibacterial activity of synthesized silver nanoparticles showed effective inhibitory. It showed that antibacterial activity increased by addition concentration of silver nano particle. The 0.008 molar concentrations of AgNPs, antibacterial activity was higher than other concentrations. Results confirmed this protocol as simple, rapid, one step, and eco-friendly, nontoxic and alternative conventional physical/chemical methods. Nanoparticle synthesis is a novel research are to search for an eco-friendly manner and green materials for potential applications in the fields of medicine and drug delivery.
Nourolhoda Razavi; Amene Zendegi-Shiraz; Zarrin Eshaghi
Abstract
This study considers identification and determination of phthalates esters in cosmetic samples. The dispersive solid phase extraction was used for extraction of analytes prior to high performance liquid chromatography analysis. The solid sorbent for extraction was polyethylene glycol grafted on cupric ...
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This study considers identification and determination of phthalates esters in cosmetic samples. The dispersive solid phase extraction was used for extraction of analytes prior to high performance liquid chromatography analysis. The solid sorbent for extraction was polyethylene glycol grafted on cupric oxide nanoparticles (PEG-g-CuO-NPs). This sorbent was first synthesized and characterized by scanning electron microscopy (SEM), Energy-dispersive X-ray(EDX) and fourier-transform infrared spectroscopy (FT-IR) then efficiently applied for extraction of analytes. The extraction conditions like amount of sorbent, kind and volume of desorption solvent, extraction and desorption time, and pH of sample solution were optimized. The validation of method carried out under optimum conditions. Linear ranges were 0.005-4 µgmL-1 with the coefficient correlation (R2) in the range of 0.9914-0.9962. The limits of detection (LODs) (3S/N) were 0.0025 to 0.005 µgmL-1 and acceptable repeatability’s (RSDs below 6.45%, n=5) obtained. Application of proposed method was investigated by extraction of phthalates in shampoo and body wash for babies which satisfaction results achieved.
Gohar Deilamy-Rad; Parisa Hossein-Khezri,; Pegah Pykarimah; Leila Elyasi
Abstract
In this study, the acid dissociation constants (pKa) of three indicators, bromocresol green, phenolphthalein and methyl orange, were determined by scanning the solution of indicators and deposited pH paper in these solutions (in each step of color-changing solution) and then chemometrics method. These ...
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In this study, the acid dissociation constants (pKa) of three indicators, bromocresol green, phenolphthalein and methyl orange, were determined by scanning the solution of indicators and deposited pH paper in these solutions (in each step of color-changing solution) and then chemometrics method. These methods are simple, fast, and inexpensive. For this reason, first, the vessels containing the indicator solution and pH paper (in each step of color-changing solution) were scanned by the scanner, and then the images of sample solutions and pH papers were transferred to a computer using Microsoft Photo Editor (Microsoft XP). RGB values were measured, in each pixel, with the image processing tool box of MATLAB. In MATLAB (2013) software, a novel program was written based on RGB values, for calculating pKa indicators. The agreement between obtained pKa by this method and values reported in the literature demonstrates the utility of the method here used.
Maryam Omidvar Motlagh; Zarrin Eshaghi; Hasan Ali Hosseini
Abstract
Contamination of water sources with chromium has become a pervasive global problem due to its wide use in industry. In this research, low-cost commercial sodium bentonite and synthesized nano bentonite were used to remove chromium ions from aqueous solutions along with electro thermal atomic absorption ...
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Contamination of water sources with chromium has become a pervasive global problem due to its wide use in industry. In this research, low-cost commercial sodium bentonite and synthesized nano bentonite were used to remove chromium ions from aqueous solutions along with electro thermal atomic absorption spectroscopy (ETAAS) and Ultraviolet-Visible Spectrophotometry (UV-Vis) were used. The morphology of the bentonite samples was studied using XRD, FTIR and scanning electron microscope (SEM) analyzes. To screen the relative importance of variables, parameters including pH, adsorption time, amount of adsorbent, volume of desorption solvent and stirring speed were studied using the Plackett Burman Design (PBD) using the Minitab 20 software. In the following, optimization was performed by using the central composite design (CCD), and the responses were evaluated. The calibration curve was plotted by drawing the absorbance against standard concentration. The linear dynamic range of 0.003-100 μg L-1 (DLR) and the correlation coefficient (R2) of 0.999 were obtained for chromium. Limit of detection (LOD) and limit of quantification (LOQ) for chromium were obtained equal to 0.002 and 0.0039 μg L-1, respectively. The relative standard deviation (RSD) of 6.93% and the relative recovery for chromium in real samples were obtained in the range 96.041% to 103.445% for ETAAS method. The values of detection limit (LOD) and limit of quantification (LOQ) by UV-Vis method were 0.007 and 0.021 µg L-1 respectively, and the dynamic linear range was (DLR) 0.05-50.00 µg L-1 with a correlation coefficient (R2) 0.998. The relative standard deviation (RSD) was 14.27% and the relative recovery of this method in real samples was attained from 95.103% to 103.692%.
Hajar Alimorad
Abstract
Topological indices are graph invariants used in theoretical chemistry to encode molecules for the design of chemical compounds with given physicochemical properties or given pharmacological and biological activities. Szeged index ( ) and Revised Szeged index ( ) of molecular graph identify some distance ...
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Topological indices are graph invariants used in theoretical chemistry to encode molecules for the design of chemical compounds with given physicochemical properties or given pharmacological and biological activities. Szeged index ( ) and Revised Szeged index ( ) of molecular graph identify some distance properties for graphs. In computational chemistry and graph theory, ( ) and ( ) were more available to test the characteristics of chemical molecular structures, and thus widely used in chemical applications. In this paper, a simple algorithm is presented for constructing the distance matrix. This algorithm is designed for calculation of and .
Nosrat Madadi Mahani
Abstract
The interactions of 6twk protein with Ectoine drug, Polyamidoamine (PAMAM) /Ectoine and histidine modified PAMAM/Ectoine were investigated using molecular docking and molecular dynamics simulation. Based on the results of molecular docking increasing of binding energy and the decreasing of inhibition ...
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The interactions of 6twk protein with Ectoine drug, Polyamidoamine (PAMAM) /Ectoine and histidine modified PAMAM/Ectoine were investigated using molecular docking and molecular dynamics simulation. Based on the results of molecular docking increasing of binding energy and the decreasing of inhibition constant of the compounds, increase their inhibitory activity. Protein stability in complex with these ligands was investigated using molecular dynamics simulation approach. Results molecular dynamics simulation displayed that histidine modified PAMAM/Ectoine with the lowest mean square displacement (MSD) is the better suitable to deliver the ectoine drug. This causes the most controlled/diffusion of ectoine drug molecule. So, histidine modified PAMAM/Ectoine conjugate can be introduced for further investigations on interaction of ectoine drug and 6twk protein.
Marjan Rafiee; Parvane Amini; Shahla Mozaffari; Juliet Ordukhanian
Abstract
Fuel cells can directly convert chemical energy into electric energy with high conversion efficiency and no pollution. Among many factors affecting the chemical-electrical energy conversion, oxygen reduction reaction (ORR) on cathode is the pivot in fuel cell. This reaction is a kinetically slow process, ...
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Fuel cells can directly convert chemical energy into electric energy with high conversion efficiency and no pollution. Among many factors affecting the chemical-electrical energy conversion, oxygen reduction reaction (ORR) on cathode is the pivot in fuel cell. This reaction is a kinetically slow process, which dominates the overall performance of a fuel cell. The ORR can proceed through two ways. One is a direct four-electron pathway, in which O2 is reduced directly to water without involvement of hydrogen peroxide. The other is a less efficient two-step two-electron pathway in which hydrogen peroxide is formed as an intermediate. To achieve a high efficiency fuel cell, the four-electron pathway is expected to occur. Because the ORR process is very slow in nature, catalysts must be used to facilitate the four-electron pathway to boost the efficiency of fuel cells. Traditionally, such electro catalysts are platinum and its alloys, but they are expensive and susceptible to time-dependent drift and CO poisoning, which limits large-scale application of the fuel cell. There have been intensive research efforts to reduce or replace Pt and Pt based alloys electrodes in fuel cell. In this work using calculated NMR and NQR parameters in some nitrogen-containing graphene sheets (with one or two nitrogen), the effect of nitrogen atom on charge density of carbon atoms was studied. The results showed that in the presence of nitrogen, charge density of some carbon atoms decreased and these atoms are better candidate as catalyst active site than pure graphene.
Mayur Sanjay Tekade; Pallavi M Patil
Abstract
The purpose of this study was to create, optimise, and validate a high-performance thin layer chromatographic (HPTLC) method for identifying Molnupiravir (MOL) and its impurity (IMP-MOL). (3aR,4R,6R,6aR) -6-(4-(hydroxyamino) -2-oxopyrimidin-1(2H)-yl) Molnupiravir A is 2,2 dimethyltetrahydrofuro [3,4-d][1,3]dioxol-4-yl)methyl ...
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The purpose of this study was to create, optimise, and validate a high-performance thin layer chromatographic (HPTLC) method for identifying Molnupiravir (MOL) and its impurity (IMP-MOL). (3aR,4R,6R,6aR) -6-(4-(hydroxyamino) -2-oxopyrimidin-1(2H)-yl) Molnupiravir A is 2,2 dimethyltetrahydrofuro [3,4-d][1,3]dioxol-4-yl)methyl isobutyrate (MOL IMP) Over concentration ranges of 0.1 µg/band to 0.6 µg/band and 0.02 to 0.6 µg/band, the proposed technique was employed to analyse Molnupiravir and its impurity, with mean percentage recovery of 99.92% ±1.521 and 99.28% ±2.296, respectively. This method has been done with the separation of two components and ends with the densitometric measurement of the separated peaks at 276 nm. The separation was done on silica gel HPTLC F254 plates with a Toluene: n-Butanol: Methanol: Water developing system (5:3:1.5:0.5, by volume). The MOL was kept under conditions like oxidative, hydrolytic, thermal stress, and photolytic tests that the International Conference on Harmonization (ICH) requires. In acid, alkali, and oxidative hydrolysis, the MOL was unstable, but it was not affected by acidic, heat or UV light. The alkaline degradation of Molnupiravir was studied using the proposed HPTLC approach. The degradant are separated using HPTLC method, and their structures are confirmed using IR, MS, and NMR spectrum data.
Shahryar Pashaie; nahid mohammadiasl; soleyman hosseinzadeh
Abstract
In present work, orange peel derived activated carbon (OPAC) /Fe3O4 loaded into polyurethane biocomposites were synthesized with different weight fractions of (OPAC)/Fe3O4 via, 0.5, 1 and 2 wt% filler in the biocomposites. The physico – mechanical, thermal characteristics and magnetic properties ...
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In present work, orange peel derived activated carbon (OPAC) /Fe3O4 loaded into polyurethane biocomposites were synthesized with different weight fractions of (OPAC)/Fe3O4 via, 0.5, 1 and 2 wt% filler in the biocomposites. The physico – mechanical, thermal characteristics and magnetic properties of fabricated (OPAC)/Fe3O4 filled biocomposites have been measured by using DSC, TGA, DMA and VSM. A slight improvement in thermal stability was noticed for (OPAC)/Fe3O4 loaded biocomposites. The PU/(OPAC)/Fe3O4biocomposites are thermally stable up to 250ºC and completely degraded above 520 ºC. The biocomposites degradation kinetic parameters for each step of the thermal degradation processes have been studied using two mathematical models namely, Coats–Redfern and Broido's methods. The PU/(OPAC)Fe3O4 biocomposites showed high mechanical, magnetic, thermal properties at a low loading of 2 wt.%, and could potentially be used for a wide range of applications.
Abdolhamid Hatefi-Mehrjerdi; ُُSoghra Rafiei Boldaji; Mohammad Reza Yaftian; Hassan Shayani-Jam
Abstract
A novel Buprenorphine (BPR) sensor is fabricated based on nanocomposite film of benzene-1,3-disulfonate anion doped overoxidized polypyrrole/multiwalled carbon modified glassy carbon electrode. The carbon nanotubes were drop-casted on bare electrode, and then thin layer of benzene-1,3-disulfonate-doped ...
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A novel Buprenorphine (BPR) sensor is fabricated based on nanocomposite film of benzene-1,3-disulfonate anion doped overoxidized polypyrrole/multiwalled carbon modified glassy carbon electrode. The carbon nanotubes were drop-casted on bare electrode, and then thin layer of benzene-1,3-disulfonate-doped overoxidized polypyrrole formed electrochemically on it. Effect of experimental conditions involving supporting electrolyte pH, carbon nanotubes suspension drop size, and the number of potential cycles in overoxidized polymerization were optimized by monitoring the voltammetry responses of the modified electrode. Then the optimized modified electrode was used for electrochemical sensing of BPR by differential pulse voltammetry, which exhibited a linear growth with high sensitivity in anodic peak currents at the BPR concentration range of 0.06-40 µM, and a detection limit of 28 nM. Finally, the determination of BPR in urine real samples was performed by the new sensor and satisfactory results obtained.
Kobra Sadat Hasheminasab; Karim Shahbazi
Abstract
In the present work, switchable hydrophilic solvent-based extraction (SHSE) followed by high performance liquid chromatography with UV detection (HPLC-UV) was used to determine free amino acids in fertilizer samples. During the phase transformation of SHSE, the organic phase appeared to effectively capture ...
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In the present work, switchable hydrophilic solvent-based extraction (SHSE) followed by high performance liquid chromatography with UV detection (HPLC-UV) was used to determine free amino acids in fertilizer samples. During the phase transformation of SHSE, the organic phase appeared to effectively capture the target analytes. In this extraction technique, 200 μL of a water-immiscible solvent (dipropylamine) is used, which can be solubilized in the acidic aqueous phase. Phase separation is then brought about by the addition of sodium hydroxide. The variables affecting this method were optimized to achieve the best extraction efficiency. The optimized conditions included: volume of sample 25 mL, volume of extraction solvent 200 μL, and extraction time 2 min. Under the optimal experimental conditions, good detection limits (0.0006-0.0021 µmol ml-1), linearities (R2 > 0.997), and precision (relative standard deviation less than 5.0%) were obtained. Finally, the developed method was successfully applied to the determination of target analytes in different types of fertilizer samples and acceptable recoveries (> 97.2%) were obtained.
