Amirkhosro Beheshti; Sayed Zia Mohammadi; Mahdokht Arjmand Kermani; Tahereh Rohani
Abstract
Addressed herein, Bismuth sulfide (Bi2S3) as a synthetic semiconductor chalcogenide applied in fabrication process of an aptasensor as a signal promoter for ultra-trace detection of aflatoxin B1(AFB1). The analytical signal was improved by using optimized amounts of Bi2S3 for electrode modification. ...
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Addressed herein, Bismuth sulfide (Bi2S3) as a synthetic semiconductor chalcogenide applied in fabrication process of an aptasensor as a signal promoter for ultra-trace detection of aflatoxin B1(AFB1). The analytical signal was improved by using optimized amounts of Bi2S3 for electrode modification. The AFB1 Aptamer single strand type(SSDNA) was simply immobilized on the cross section of a pencil lead through polydopamine layers. A wide concentration range of trace amounts of AFB1(0.3-630nM) was supported by the fabricated aptasensor (pencil/polydopamine@Bi2S3/aptamer) using differential pulse voltammetry. Simple fabrication and no needing to electrode refreshment were part of the advantages of the suggested aptasensor. Finally, very low resulted detection limit(0.04nM) with a great sensitivity (0.076µA/nM) and also appropriate stability and repeatability led to application of the aptasensor in real sample analysis such as wheat flour with brilliant recovery percentages.
Amirkhosro Beheshti; Tahereh Rohani; Sayed Zia Mohammadi; Maryam Dadkhodazadeh
Abstract
Molybdenum disulfide as a transition metal dichalcogenide was prepared by a hydrothermal method and hybridized with graphene oxide (MoS2/GO). The as-prepared materials were investigated by Fourier transform infra-red spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray elemental analysis ...
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Molybdenum disulfide as a transition metal dichalcogenide was prepared by a hydrothermal method and hybridized with graphene oxide (MoS2/GO). The as-prepared materials were investigated by Fourier transform infra-red spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray elemental analysis (EDX) techniques as well transmission electron microscopy (TEM) image. The nanomaterial with its electrocatalytic properties was applied as an electro-nanocatalyst for loading on a glassy carbon electrode (MoS2/GO-GCE) for detection of carbamazepine as an anti-epileptic in real body samples. The simple and low-cost developed electrochemical sensor detected carbamazepine with a vast linear concentration range(30-350nM), very low detection limit about 6.0nM and significant sensitivity equal to 0.134µA/nM.
Tahereh Rohani; Sayed Zia Mohammadi; Amirkhosro Beheshti; Hooshang Hamidian; Nasrin Gholamhosein Zadeh
Abstract
Herein, the electrooxidation of ascorbic acid and folic acid, as two essential vitamins, on the surface of the carbon ceramic electrode modified by polydopamine and copper (Cu/PDA/CCE) was investigated. Poly dopamine was fabricated by applying electro deposition conditions. Initial electrochemical characteristics ...
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Herein, the electrooxidation of ascorbic acid and folic acid, as two essential vitamins, on the surface of the carbon ceramic electrode modified by polydopamine and copper (Cu/PDA/CCE) was investigated. Poly dopamine was fabricated by applying electro deposition conditions. Initial electrochemical characteristics were performed to study the behavior of the fabricated electrode for simultaneous detection of two biomolecules. From voltametric studies using the developed electrode, two separated anodic peaks for folic acid and ascorbic acid were found promisingly for concurrent detection of the compounds. Linear calibration diagrams were obtained in the range of 0.5 to 360 μM and 0.83 to 380 μM with detection limits of about 0.031 and 0.057 μM for folic acid and ascorbic acid, respectively. The developed electrode was applied in human urine sample analysis with satisfying results
Nosrat Madadi Mahani; Khadije Anjomshoaa; Sayed Zia Mohammadi
Abstract
N-salicyloyl tryptamine derivatives as anti-neuroinflammatory agents have a potent strategy to cure neuroinflammatory diseases including Alzheimer and Parkinson. Computational methods of quantitative structure properties relationships (QSPR) and molecular dynamics were successfully used to design of ...
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N-salicyloyl tryptamine derivatives as anti-neuroinflammatory agents have a potent strategy to cure neuroinflammatory diseases including Alzheimer and Parkinson. Computational methods of quantitative structure properties relationships (QSPR) and molecular dynamics were successfully used to design of four novel N-salicyloyl tryptamine with improved properties. The QSPR model of five variables was presented to predict anti- neuroinflammatory activity of N-salicyloyl tryptamine derivatives. The quantum descriptors as Hartree Fock energy, ionization energy, softness, dipole moment and the thermal energy, were calculated with density functional theory at the B3LYP/6-311G level. Cross validation of multivariate linear regression (MLR) was used to build and evaluate the model QSPR. The model possesses coefficients of the highest squared correlation coefficient (R2) of 0.900 for the training set and 0.817 for the test set. The statistical results exhibited high internal and external consistency as demonstrated by the validation methods. Three of designed compounds showed good pharmacokinetic properties by QSPR predictions. These results provided strong guidance for the discovery and design of novel potential anti- neuroinflammatory compounds. Also, the adsorption of the designed compounds on functionalized carbon nanotube (8, 0) was investigated using molecular dynamics simulation with COMPASS force field. Results indicated that the adsorption of designed N-salicyloyl tryptamine derivatives on f-CNT involves a partial π–π interaction and hydrogen bonding. The study of investigation the interactions of N-salicyloyl tryptamine with f-CNT (8, 0) can be useful for finding the main CNT-based carriers for these derrivatives.
Sayed Zia Mohammadi; Somayeh Tajik; Hadi Beitollahi; Zohreh Barani
Abstract
In the present study, the cysteamine electrochemical features were explored by La2O3/Co3O4 nanocomposite-modified screen printed electrode (La2O3/Co3O4/SPE) using voltammetry, chronoamperometry, and differential pulse voltammetry (DPV) techniques. The synthesized La2O3/Co3O4 nanocomposite qualities were ...
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In the present study, the cysteamine electrochemical features were explored by La2O3/Co3O4 nanocomposite-modified screen printed electrode (La2O3/Co3O4/SPE) using voltammetry, chronoamperometry, and differential pulse voltammetry (DPV) techniques. The synthesized La2O3/Co3O4 nanocomposite qualities were considered by SEM, FT-IR, and XRD analyses. Exploiting the modified SPE electrode with La2O3/Co3O4 nanocomposite, the cysteamine electrooxidation kinetics was significantly enhanced by reducing the anodic over-potential. The constructed La2O3/Co3O4/SPE revealed voltammetric reactions of high sensitivity for cysteamine, resulting in a highly appropriate means of trace levels cysteamine measurement. The electrooxidation peak currents for cysteamine were found to change linearly in relation to its concentrations (1.0–700.0 μM) in detection limit of 0.3 μM. La2O3/Co3O4/SPE was utilized for the cysteamine quantification in real specimens.
Sayed Zia Mohammadi; Maryam Balengei; Alieyeh Pourhasanghani; Samieh Fozooni; Asghar Amiri
Volume 5, Issue 1 , March 2018, , Pages 1-8
Abstract
A preconcentration procedure, based on the coprecipitation of Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions using a new organic coprecipitant, (2-(4-{[(4-{5-oxo-4-[1-(2-thienyl) methylidene]- 4,5-dihydro- 1,3- oxazole-2-yl} phenyl) imino] methyl} phenyl) methylidene ] amino} phenyl) -4-[ 1-phenyl methylidene] ...
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A preconcentration procedure, based on the coprecipitation of Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions using a new organic coprecipitant, (2-(4-{[(4-{5-oxo-4-[1-(2-thienyl) methylidene]- 4,5-dihydro- 1,3- oxazole-2-yl} phenyl) imino] methyl} phenyl) methylidene ] amino} phenyl) -4-[ 1-phenyl methylidene] -1,3-oxazole-5(4H)-one (OTMDO) without adding any carrier element has been developed. The resultant concentrated elements were determined by using flame atomic absorption spectrometer. The influences of some analytical parameters including pH, amount of the coprecipitant, standing time, centrifugation rate and time, sample volume and diverse ions were investigated on the quantitative recoveries of analyte ions. Under the optimized experimental conditions, the calibration curves for the analyte ions were studied. The relative standard deviations for seven replicate determinations of a mixture of 0.1 mg mL−1 Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions in the original solution were 2.5, 2.4, 2.2, 2.1 and 2.5%, respectively. The detection limits based on 3Sb/m for Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions in the original solution were 1.2, 1.3, 1.2, 0.6 and 1.5 ng mL−1, respectively. The proposed method has been applied for determination of trace amounts of the analyte ions in the standard, water samples; brewed tea; tobacco samples and satisfactory results were obtained.
Mohammad Ali Karimi; Abdolhamid Hatefi-Mehrjardi; Alireza Mohadesi; Sayed Zia Mohammadi; Mehdi Taghdiri; Javad Yarahmadi; Havva Mahmoodian; Shahla Nezhad Khorasani
Volume 1, Issue 1 , March 2014, , Pages 7-11
Abstract
In this work, a new, simple and fast method for the solid phase extraction-spectrophotometric determination of phosphate using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs) has been developed. The determination of phosphate is based on the molybdenum ...
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In this work, a new, simple and fast method for the solid phase extraction-spectrophotometric determination of phosphate using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs) has been developed. The determination of phosphate is based on the molybdenum blue method which was monitored at λmax of 810 nm. MNPs and ACMNPs characterized by SEM, VSM, and XRD spectroscopy. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. Under the optimal experimental conditions, the preconcentration factor (PF), detection limit (DL), linear range (LR) and relative standard deviation (RSD) of phosphate were 80 (for 400 mL of sample solution), 0.038 µg mL−1, 0.8-10.0 µg mL−1 and 2.5 % (for 5.0 µg mL-1, n=7), respectively. The proposed method was successfully applied to the separation/preconcentration and determination of phosphate in different water samples and suitable recoveries were obtained.
