Abbas Afkhami
Bu-Ali Sina University, Faculty of Chemistry, Faculty Member
This work presents a simple, rapid, and novel method for simultaneous determination of binary mixtures of some surfactants using continuous wavelet transformation. The method is based on the difference in the effect of surfactants... more
This work presents a simple, rapid, and novel method for simultaneous determination of binary mixtures of some surfactants using continuous wavelet transformation. The method is based on the difference in the effect of surfactants Cetyltrimethylammoniumbromide (CTAB), dodecyl trimethylammonium bromide (DTAB), cetylpyridinium bromide (CPB) and TritonX-100 (TX-100) on the absorption spectra of complex of Beryllium with Chrome Azurol S (CAS) at
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The iontophoresis delivery of insulin (INS) remains a serious challenge due to the low permeability of the drug through the skin. This work aims to investigate the potential of water-soluble polypyrrole nanoparticles (WS-PPyNPs) as a drug... more
The iontophoresis delivery of insulin (INS) remains a serious challenge due to the low permeability of the drug through the skin. This work aims to investigate the potential of water-soluble polypyrrole nanoparticles (WS-PPyNPs) as a drug donor matrix for controlled transdermal iontophoresis of INS. WS-PPyNPs have been prepared via a simple chemical polymerization in the presence of sodium dodecyl sulfate (SDS) as both dopant and the stabilizing agent. The synthesis of the soluble polymer was characterized using field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), fluorescence spectroscopy, and Fourier transform infrared (FT–IR) spectroscopy. The loading mechanism of INS onto the WS-PPyNPs is based on the fact that the drug molecules can be replaced with doped dodecyl sulfate. A two-compartment Franz-type diffusion cell was employed to study the effect of current density, formulation pH, INS concentration, and sodium chloride concentration on anodal i...
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Phosphorylation of PI3Kγ as a member of lipid kinases-enzymes, plays a crucial role in regulating immune cells through the generation of intracellular signals. Deregulation of this pathway is involved in several tumors. In this research,... more
Phosphorylation of PI3Kγ as a member of lipid kinases-enzymes, plays a crucial role in regulating immune cells through the generation of intracellular signals. Deregulation of this pathway is involved in several tumors. In this research, diverse sets of potent and selective isoform-specific PI3Kγ inhibitors whose drug-likeness was confirmed based on Lipinski’s rule of five were used in the modeling process. Genetic algorithm (GA)-based multivariate analysis was employed on the half-maximal inhibitory concentration (IC50) of them. In this way, multiple linear regression (MLR) and artificial neural network (ANN) algorithm, were used to QSAR models construction on 245 compounds with a wide range of pIC50 (5.23–9.32). The stability and robustness of the models have been evaluated by external and internal validation methods (R2 0.623–0.642, RMSE 0.464–0.473, F 40.114, Q2LOO 0.600, and R2y-random 0.011). External verification using a wide variety of structures out of the training and test...
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Abstract The development of preconcentration methods in the design of electrochemical sensors is attractive due to the lack of efficient strategy for the preconcentration of organic analytes. Herein, we described the employment of... more
Abstract The development of preconcentration methods in the design of electrochemical sensors is attractive due to the lack of efficient strategy for the preconcentration of organic analytes. Herein, we described the employment of electropolymerization as a novel preconcentration approach in the electrochemical determination of melamine (Mel). In this effort, the preconcentration of Mel occurred at a glassy carbon electrode modified with overoxidized Poly-(para–aminophenol) film (GCE/Ox-PPAP) using the potentiodynamic technique. In fact, non-electroactive Mel was electrochemically converted into electroactive poly-(melamine) (PMel) during the electrochemical preconcentration step. The preconcentrated Mel was quantified using the square wave voltammetry (SWV), as the electro-analytical signal. The electrochemical preconcentration step was studied using cyclic voltammetry (CV), computer simulation, electrochemical impedance spectroscopy (EIS), and field emission scanning electron microscope (FESEM) techniques. GCE/Ox-PPAP revealed a good calibration sensitivity of 4.718 μA L μmol −1 in the linear range of 2.0 to 60 μmol L−1, and a limit of detection (LOD) of 0.34 µmol L−1 (S/N = 3). The obtained LOD is lower than the safety limit of Mel in milk and dairy products. Moreover, in this work, the electropolymerization process as the electrochemical preconcentration approach leads to the selective determination of Mel in the presence of possible interferences. Finally, the developed method was successfully used for the Mel detection in real milk samples. The obtained results will also open up opportunities for the design of novel electroanalytical method using a simple strategy.
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A method based on the ultrasound-assisted solidification of floating drop microextraction technique was developed for the spectrophotometric and spectrofluorimetric determination of curcumin in turmeric powder. In this work a small volume... more
A method based on the ultrasound-assisted solidification of floating drop microextraction technique was developed for the spectrophotometric and spectrofluorimetric determination of curcumin in turmeric powder. In this work a small volume of an organic solvent was floated on the surface of an aqueous solution. After sonication the organic solvent is solidified and separated. The effect of extraction parameters such as type and the volume of organic solvent, temperature, salt addition and exposure time, on the extraction recovery was investigated and optimized. Finally, the method droplet was used for the determination of analyte. Under the optimum extraction conditions, a linear range of 0.006–30 μg mL-1 and a relative standard deviation (RSD) of 2.72% for curcumin wasachieved. Limits of detection of 7 and 2 ng mL-1 curcumin was obtained for the spectrophotometric and spectrofluometric methods, respectively. The obtained results show that the application of this method can be succes...
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In the present study, a new chemically modified carbon paste electrode (CPE) is constructed for rapid, accurate, simple, highly sensitive, and selective determination of Mo (VI) using differential pulse voltammetry. The electrode was... more
In the present study, a new chemically modified carbon paste electrode (CPE) is constructed for rapid, accurate, simple, highly sensitive, and selective determination of Mo (VI) using differential pulse voltammetry. The electrode was prepared using magnetic nickel zinc ferrite nanocomposite (Ni0.5Zn0.5Fe2O4), as the modifier in CPE (Ni0.5Zn0.5Fe2O4/CPE). Mo (VI) was determined after preconcentration at the surface of the modified electrode at -0.7 V vs. Ag/AgCl. Under the optimal conditions, the linear dynamic range and limit of detection were 0.005-1.00 and 0.003 µgmL-1, respectively. Ten successive measurements of 0.06 and 0.70 µg mL-1 of Mo (VI) ions showed the relative standard deviation of 3.20 and 1.98 %, respectively. The reproducibility and stability of the electrode response were also studied. Investigation of the effects of different cations and anions on the determination of Mo (VI) indicated that the electrode is highly selective. Furthermore, the present method was appl...
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In an overview, the relationships between activity, property, and chemical structure of the anthracycline derivatives, as topoisomerase II enzyme inhibitors, were studied in pairs. These analogs were investigated in three categories with... more
In an overview, the relationships between activity, property, and chemical structure of the anthracycline derivatives, as topoisomerase II enzyme inhibitors, were studied in pairs. These analogs were investigated in three categories with known half-maximal inhibitory concentration (IC50), known octanol/water partition coefficient (logP), and both IC50 and logP unknown values. The QSAR and QSPR models were developed on analogs of the first and second groups, respectively. LogP was related to calculated pIC50 ((pIC50)calc) surprisingly (R2 = 0.929, Q2LOO = 0.910, RMSE = 0.235, F = 157.511). External verification was performed through comparing calculated logP (logPcalc) with three programs using 77 analogs out of the training and test sets. In application domain of the model, the suggested model had the highest correlation with ClogP method (R = 0.744) and this was better than the correlation between milogP–ClogP (R = 0.724), AlogP–ClogP (R = 0.662), and AlogP–milogP (R = 0.691). Furthermore, in the case of analogs possessing a long carbon chain substitution (nc ≥ 3), estimation methods had a significant error in calculation logP, while our suggested model provides more accurate results. The proposed algorithm can be useful in primary screening among anthracycline derivatives to select potent drug candidates.
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The preparation of nitrogen-doped graphene quantum dots (N-GQDs), by a simple and inexpensive synthetic procedure, is reported with blue emission and a high quantum yield of 78%.
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Abstract A sensitive fluorescence probe based on 3-mercaptopropionic acid (MPA) capped cadmium-sulfide quantum dots (CdS QDs) was prepared for determination of ciprofloxacin (CIP) in real samples. The synthesized MPA capped CdS QDs was... more
Abstract A sensitive fluorescence probe based on 3-mercaptopropionic acid (MPA) capped cadmium-sulfide quantum dots (CdS QDs) was prepared for determination of ciprofloxacin (CIP) in real samples. The synthesized MPA capped CdS QDs was characterized using fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) measurements. Based on the results, the fluorescence of MPA capped CdS QDs was quenched in presence of Cu 2+ that it could have occurred because of the nonradiative electron–hole recombination annihilation through an electron transfer process. Subsequently, the fluorescence of MPA capped CdS QDs mixed with the Cu 2+ could be recovered after the addition of CIP due to its strong affinities for Cu 2+ . The recovered fluorescence intensity of capped CdS QDs was proportional to the concentration of CIP in the ranges of 0.13–150.0 μmol L −1 and the detection limit was 0.04 μmol L −1 . The established method showed a good selectivity for CIP among several kinds of ions and biomolecules. The fluorescent probe was successfully applied to determine CIP in pharmaceutical preparation and human serum samples.
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From a medical or clinical point of view, to assess toxicity, adverse effects, interactions and therapeutic efficiency, monitoring drug levels in body fluids, such as urine and plasma, has become increasingly necessary.
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A novel and sensitive extraction procedure using maghemite nanoparticles (gamma-Fe(2)O(3)) modified with sodium dodecyl sulfate (SDS), as an efficient solid phase, was developed for removal, preconcentration and spectrophotometric... more
A novel and sensitive extraction procedure using maghemite nanoparticles (gamma-Fe(2)O(3)) modified with sodium dodecyl sulfate (SDS), as an efficient solid phase, was developed for removal, preconcentration and spectrophotometric determination of trace amounts of malachite green (MG) and leuco-malachite green (LMG). Combination of nanoparticle adsorption and easily magnetic separation was used to extraction and desorption of MG and LMG. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. Maghemite nanoparticles were prepared by co-precipitation method and their surfaces were modified by SDS. The size and properties of the produced maghemite nanoparticles was determined by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and BET analysis. MG and LMG became adsorbed at pH 3.0. LMG was oxidized to MG by adsorption on maghemite nanoparticles. The adsorbed MG was then desorbed and determined spectrophotometrically. The calibration graph was linear in the range 0.50-250.00 ng mL(-1) of MG and LMG with a correlation coefficient of 0.9991. The detection limit of the method for determination of MG was 0.28 ng mL(-1) and the relative standard deviation (R.S.D.) for 10.00 and 50.00 ng mL(-1) of malachite green was 1.60% (n=3) and 0.86% (n=5), respectively. A preconcentration factor of 50 was achieved in this method. The Langmuir adsorption capacity (q(max)) was found to be 227.3 mg g(-1) of the adsorbent. The method was applied to the determination of MG in fish farming water samples.
Research Interests: Chemistry, Analytical Chemistry, Chromatography, Nanoparticle, Medicine, and 15 moreMetal Nanoparticles, Adsorption, Concentration, Method, Fish Farming, Desorption, CHEMICAL SCIENCES, Coprecipitation, Ferric Compounds, Chemical Modification, Molecular Structure, Adsorption isotherm, maghemite, Malachite green, and limit of detection
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Solid phase extraction of leached bisphenol A from some polycarbonate products using surface molecularly imprinted nanospheres.
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Abstract A simple and highly sensitive extraction—spectrophotometric determination of copper (II) is described. The ion-associate formed between the copper(II)—4-(2-pyridylazo)-resorcinol (PAR) anion and tetradecyldimethylbenzylammonium... more
Abstract A simple and highly sensitive extraction—spectrophotometric determination of copper (II) is described. The ion-associate formed between the copper(II)—4-(2-pyridylazo)-resorcinol (PAR) anion and tetradecyldimethylbenzylammonium chloride (TDBA) is extracted with chloroform at pH 9.7. The absorption maximum of the extracted species occurs at 510 nm, the molar absorptivity being 8.05 (± 0.07) × 104 l mol-1 cm-1. Beer's Law is obeyed in the concentration range 0.1–0.5 μg Cu ml-1. The composition of the ion-associate is estimated to be [Cu(PAR)2(TDBA)2]. The conditional extraction constant is log K'ex ≈ 8. The interference of some cations and anions is studied. The method is suitable for analysis of waters.
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In the present work, four different spectrophotometric methods for simultaneous estimation of losartan potassium, amlodipine besilate and hydrochlorothiazide in raw materials and in formulations are described. Overlapped data was... more
In the present work, four different spectrophotometric methods for simultaneous estimation of losartan potassium, amlodipine besilate and hydrochlorothiazide in raw materials and in formulations are described. Overlapped data was quantitatively resolved by using chemometric methods, classical least squares (CLS), multiple linear regression (MLR), principal component regression (PCR) and partial least squares (PLS). Calibrations were constructed using the absorption data matrix corresponding to the concentration data matrix, with measurements in the range of 230.5-350.4 nm (Δλ = 0.1 nm) in their zero order spectra. The linearity range was found to be 8-40, 1-5 and 3-15 μg mL-1 for losartan potassium, amlodipine besilate and hydrochlorothiazide, respectively. The validity of the proposed methods was successfully assessed for analyses of drugs in the various prepared physical mixtures and in tablet formulations.
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A method for determination of trace quantities of acetaldehyde based on its inhibition effect on the malachite green-sulfite reaction is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance... more
A method for determination of trace quantities of acetaldehyde based on its inhibition effect on the malachite green-sulfite reaction is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance at 613 nm by a fixed time method of 60 seconds. The method allows the determination of acetaldehyde in the range of 0.2-10 μg/ml. The limit of detection
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The construction of graphene-based microfibers with reinforced mechanical and electrical properties has been the subject of numerous researches in recent years. However, the fabrication of graphene-based fibers with remarkable optical... more
The construction of graphene-based microfibers with reinforced mechanical and electrical properties has been the subject of numerous researches in recent years. However, the fabrication of graphene-based fibers with remarkable optical features still remains a challenge and has not been addressed so far. This paper aims to report a series of flexible self-assembled fibers, synthesized through a few-minute sonication of thermally oxidized graphene oxide nanosheets, so-called Nanoporous Over-Oxidized Graphene (NOG), in an acidic medium. These free-standing glassy fibers were classified into four distinct morphological structures and displayed a collection of intriguing optical properties comprising high transparency, strong birefringence, fixed body colorations (e.g. colorless, blue, green, and red), tunable interference marginal colorations, UV–visible-near IR fluorescence, and upconversion emissions. Moreover, they exhibited high chemical stability in strongly acidic, basic, and oxid...
Research Interests: Materials Science, Fiber Optics, Materials Chemistry, Photonics, Self Assembly, and 14 moreMedicine, Synthetic Fibers, Upconversion luminescence, Applications of Graphene, Graphene Oxide, Optical Properties, Fluorescent Materials, Graphene synthesis, Upconversion, Graphene and Graphite Oxide, Birefringence, Luminescent Materials, Graphene Macroassemblies, and Holey graphene nanosheets
A new and very simple kinetic-spectrophotometric method was developed for the simultaneous determination of binary mixtures of iodate and bromate in water samples, without prior separation steps. The method is based on the mean centering... more
A new and very simple kinetic-spectrophotometric method was developed for the simultaneous determination of binary mixtures of iodate and bromate in water samples, without prior separation steps. The method is based on the mean centering of ratio kinetic profiles, allows rapid and accurate determination of bromate and iodate. The analytical characteristics of the method such as detection limit, accuracy, precision, relative standard deviation (R.S.D.) and relative standard error (R.S.E.) for the simultaneous determination of binary mixtures of iodate and bromate were calculated. The results show that the method was capable of simultaneous determination of 0.05-1.50 microg mL(-1) each of iodate and bromate. The results allow simultaneous determination with the ratio 30:1-1:30 for iodate-bromate. The proposed method was successfully applied to the simultaneous determination of iodate and bromate in several water samples.
Research Interests: Engineering, Chemistry, Analytical Chemistry, Kinetics, Environmental Monitoring, and 15 morePharmaceutical Chemistry, Environmental Analytical Chemistry, Hazardous Materials, Molybdenum, CHEMICAL SCIENCES, Ascorbic Acid, Bromate, Phosphates, Food Sciences, Ions, Iodate, Potassium Bromate, Analytical Sciences, ENVIRONMENTAL SCIENCE AND MANAGEMENT, and Relative Standard Deviation
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ABSTRACT In this study, the binding of oxymetholone (OXM), a doping drug, to human serum albumin (HSA) was explored at pH 7.40 by spectroscopic methods including spectrofluorimetry, three dimensional excitation–emission matrix (3D EEM),... more
ABSTRACT In this study, the binding of oxymetholone (OXM), a doping drug, to human serum albumin (HSA) was explored at pH 7.40 by spectroscopic methods including spectrofluorimetry, three dimensional excitation–emission matrix (3D EEM), UV–vis absorption, resonance rayleigh scattering (RRS) and molecular docking. The fluorescence results showed that there was a considerable quenching of the intrinsic fluorescence of HSA upon binding to OXM by static quenching mechanism. The Stern–Volmer quenching constants (KSV) between OXM and HSA at three different temperatures 295, 303, 308 K, were obtained as 4.63×104, 3.05×104 and 1.49×104 L mol−1, respectively. Furthermore this interaction was confirmed by UV–vis spectrophotometric and RRS techniques. The binding site number, n, apparent binding constant, Kb, and corresponding thermodynamic parameters (ΔS, ΔH and ΔG) were measured at different temperatures. The Van der Waals and hydrogen-bond forces were found to stabilize OXM–HSA complex. The distance (r) between the donor and acceptor was obtained from Förster׳s theory of fluorescence resonance energy transfer (FRET) and found to be 1.67 nm. The 3D EEM showed that OXM slightly changes the secondary structure of HSA. Furthermore, the molecular docking was employed for identification of drug binding sites and interaction of OXM with amino acid residues.
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The adsorption of iodine onto silica coated magnetite nanoparticles (im-SCMNPs) that modified with imidazole was investigated for removal of high concentrations of iodine from wastewater. Modified silica magnetite nanoparticles showed... more
The adsorption of iodine onto silica coated magnetite nanoparticles (im-SCMNPs) that modified with imidazole was investigated for removal of high concentrations of iodine from wastewater. Modified silica magnetite nanoparticles showed high efficiency in removing iodine from wastewater samples. The optimum pH for iodine removal was 7.0–8.0. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. The size of the produced magnetite nanoparticles was determined by X-ray diffraction analysis and scanning electron microscopy. Synthesized magnetite nanoparticles showed the high adsorption capacity and would be a good method to increase adsorption efficiency for the removal of iodine in a wastewater treatment process. The Langmuir adsorption capacity (qmax) was found to be 140.84 mg/g of the adsorbent.