Mahmoud Roushani - Academia.edu (original) (raw)

Papers by Mahmoud Roushani

Microchimica Acta

A dual recognition biosensor was developed via introducing aptamer strings and molecular imprinti... more A dual recognition biosensor was developed via introducing aptamer strings and molecular imprinting polymer (MIP) for the selective detection of intact SARS-CoV-2 virus based on screen printed carbon electrode (SPCE) modified with nickelbenzene tricarboxylic acid-metal-organic framework (Ni 3 (BTC) 2 MOF) synthesized by in situ growth method, SARS-CoV-2 S protein-specific amino-aptamer and electropolymerization of dopamine (ePDA). The proposed biosensor showed an excellent linear relationship between charge transfer resistance (R ct) and increase in virus concentration in the range 10 to 10 8 plaque-forming units/mL (PFU/mL) with a low detection limit of 3.3 ± 0.04 PFU/mL and response time of 20 min. Compared with single-element sensors (aptamer or MIP), it showed higher selectivity for the SARS-CoV-2 virus and facilitated detection in real samples.

Analytical and Bioanalytical Chemistry, 2022

This study purposes designing a new aptasensor to detect aflatoxin B1 (AFB1). The AFB1 aptasensor... more This study purposes designing a new aptasensor to detect aflatoxin B1 (AFB1). The AFB1 aptasensor was developed by growing gold nanoparticles on the surface of nickel-based metal-organic framework nanosheets (AuNPs/Ni-MOF) and an electroactive indicator (p-biphenol, PBP). The AFB1 aptamer was immobilized on the AuNPs/Ni-MOF and then hybridized with the complementary DNA (cDNA). PBP was intercalated within the double helix of the cDNA-aptamer. The difference between electrochemical responses of intercalated PBP before and after incubation of AFB1 with the immobilized aptamer was considered as an analytical response. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to monitor the construction processes of the aptasensor. By recording the differential pulse voltammograms of PBP in phosphate buffer (pH 7.0, 0.1 M), the linear range and the detection limit of AFB1 were found to be 5.0 × 10-3-150.0 ng mL-1 and 1.0 × 10-3 ng mL-1 (S/N = 3), respectively. Finally, the designed aptasensor has been successfully used to measure AFB1 in a rice flour sample with satisfying results. Schematic illustrated the different steps of constructing the electrochemical aptasensor based on Au nanoparticles decorated on Ni-metal-organic framework nanosheets and p-biphenol electroactive label for measuring aflatoxin B1 (AFB1).

Materials Science and Engineering: C, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Electroanalytical Chemistry, 2018

In this work, a newly competitive electrochemical sensor for oxazepam detection was successfully ... more In this work, a newly competitive electrochemical sensor for oxazepam detection was successfully achieved. Ag-Pt core-shell nanoparticles supported on graphene nanosheets were used for the sensor construction (Ag-Pt/GRs/GCE) for the determination of oxazepam in real samples including serum, urine and tablets. The properties of materials were characterized by transmission electron microscopy, scanning electron microscope, electrochemical impedance spectroscopy and voltammetry. The voltammetric obtained data confirm the significant enhancement of reduction current and reduction overvoltage oxazepam at a surface of Ag-Pt/GRs/GCE. After optimization of electrochemical parameters employing this modified electrode at pH 7.0, the reduction peak currents for oxazepam was found linearly with concentrations in the range of 0.05-150.0 µM with detection limit of 42 ± 1 nM using differential pulse voltammetry method. The simple fabrication method, specificity, high sensitivity, good reproducibility and long-term stability as well as acceptable accuracy for oxazepam detection in real samples are the main advantages of this sensor, which might have broad applications in drug diagnostics.

Communications in Soil Science and Plant Analysis, 2017

In this study, a new Co 3 O 4 nanoparticles (NPs) coated with sodium dodecyl sulphate (SDS) is de... more In this study, a new Co 3 O 4 nanoparticles (NPs) coated with sodium dodecyl sulphate (SDS) is developed for preconcentration of trace amounts of cadmium ions (Cd 2+) as a prior step to its determination by flame atomic absorption spectrometry (FAAS). The effects of various parameters, including pH of sample solution, amount of sorbent, flow rates of solution and eluent, sample volume, type, and least amount of the eluent for elution of the Cd 2+ from Co 3 O 4 NPs were studied and optimized. Experimental conditions for effective separation of trace levels of the Cd 2+ were optimized with respect to different experimental parameters in Column method. Under the best experimental conditions, the calibration curve was linear in the range of 1.0-500.0 ng.mL −1 of cadmium (Cd) with R 2 = 0.999. The detection limit was 0.4ng.mL −1 in the original solution (3S b /m) and the relative standard deviation for eight replicate determination of 0.1µg.mL −1 Cd was ±2.1%. The method was validated by the analysis of a certified reference material with the results being in agreement with those quoted by manufactures. The developed method was successfully applied to the extraction and determination of Cd in water and food samples with satisfactory results.

Bulletin of Environmental Contamination and Toxicology, 2017

2011). Understanding the persistence and degradation of herbicides in soil is essential to the ac... more 2011). Understanding the persistence and degradation of herbicides in soil is essential to the accurate assessment of its effects on environment and important in warranting the safe use of these products for next sensitive crops in rotation. Sulfosulfuron and tribenuron methyl belong to the class of sulfonylurea herbicides used extensively throughout the world for control of broadleaf and grass weeds in crops including cereals and corn (Geir et al. 1998; He et al. 2012). The inhibiting of acetolactate synthase (ALS) an essential enzyme in the biosynthetic pathway of branched chain amino acid is a known mode of action for these herbicides (Walter et al. 2014). Degradation and persistence of these herbicides is widely affected by several soil-related factors such as pH, texture, organic matter content, moisture, and microorganisms (Grey and McCullough 2012; Pankaj et al. 2015; Cessna et al. 2015). Bedmar et al. (2006) in the study of dissipation and persistence of sulfonylurea herbicides in different soils found more degradation rates in the soil with low level of pH and high level of organic matter content. Based on different conditions the half-life of these herbicides in agricultural fields ranges from few days to couple of years. These herbicides have a wide range of carry over effect on different crop depending on factors such as crop species, herbicide application rate, soil characteristics and environmental conditions. Mehdizadeh et al. (2016) found that sulfosulfuron and tribenuron methyl soil residues affect barley, corn, oilseed rape and sugar beet at very low concentration levels such as 0.06 and 0.1 μg a.i. kg −1 soil. Detection the trace concentration of sulfonylurea residues in soil samples requires the use of sensitive instrumental methods along with accurate extraction and purification procedures. Different instrumental methods have been developed for analysis of these compounds in soil environment. HPLC (Wang et al. 2012; Yan et al. 2016) GC (Rouchaud et al. 2001) and LC/MS (Ghosh Abstract A HPLC-UV detection system was used for determination of sulfosulfuron and tribenuron methyl residues from soils. The soils were fortified with sulfosulfuron and tribenuron methyl at rates of 26 and 15 g a.i. ha −1 respectively and samples were taken randomly on 0 (2 h), 1, 2, 4, 10, 20, 40, 60, 90 and 120 days after treatment. The final extracts were prepared for analysis by HPLC. The results showed that degradation of both herbicides in the silty loam soil was faster than sandy loam soil. Half-life of sulfosulfuron was ranged from 5.37 to 10.82 days however this value for tribenuron methyl was ranged from 3.23 to 5.72 days on different soils. The residue of both herbicides at 120 days after application in wheat field had no toxicitic effect on lentil. It was concluded that HPLC analysis procedure was an appropriate method for determination of these herbicides from soils.

Microchimica Acta, 2016

A carbon ceramic electrode (CCE) was fabricated from a composite consisting of sol-gel, ceramic g... more A carbon ceramic electrode (CCE) was fabricated from a composite consisting of sol-gel, ceramic graphite, multi-walled carbon nanotubes and the natural carotenoid crocin. The resulting sensor is shown to allow for the determination of NADH at a rather low working potential of 0.22 V (vs. Ag/AgCl). The heterogeneous electron transfer rate constant (k s) and the surface coverage of the modified electrode are 16.8 s −1 and 22 pmol•cm −2 , respectively. The sensor shows excellent and linear response in solutions of pH 7.0 over the 0.5 to 100 μM NADH concentration range, a 0.1 μM detection limit, and a sensitivity of 251.3 nA•μM −1 •cm −2 .

Analytical Biochemistry, 2016

Design of folding-based impedimetric aptasensor for determination of the non-steroidal anti-infla... more Design of folding-based impedimetric aptasensor for determination of the non-steroidal anti-inflammatory drug,

Catalysis Communications, 2015

Analytica chimica acta, 2015

Based on the conformational changes of the aptamer-functionalized gold nanoparticles (AuNPs) onto... more Based on the conformational changes of the aptamer-functionalized gold nanoparticles (AuNPs) onto MWCNTs/IL/Chit nanocomposite as the support platform, we have developed a sensitive and selective electrochemical aptasensor for the detection of cocaine. The 5'-amine-3'-AuNP terminated aptamer is covalently attached to a MWCNTs/IL/Chit nanocomposite. The interaction of cocaine with the aptamer functionalized AuNP caused the aptamer to be folded and the AuNPs with negative charge at the end of the aptamer came to the near of electrode surface therefore, the electron transfer between ferricyanide (K3Fe(CN)6) as redox probe and electrode surface was inhibited. A decreased current of (K3Fe(CN)6) was monitored by differential pulse voltammetry technique. In an optimized condition the calibration curve for cocaine concentration was linear up to 11 μM with detection limit (signal-to-noise ratio of 3) of 100 pM. To test the selectivity of the prepared aptasensor sensing platform appli...

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015

A highly sensitive method is presented for the colorimetric determination of malathion using gold... more A highly sensitive method is presented for the colorimetric determination of malathion using gold nanoparticles (AuNPs). In this approach, the synthesized AuNPs solution was stabilized by the citrate anions as their repulsion protected the AuNPs from aggregation. The synthesized AuNPs were characterized morphologically by using transmission electron microscopy technique. Malathion caps the surface of AuNPs and induces the aggregation of AuNPs in Britton-Robinson buffer solution. The reaction was monitored spectrophotometrically by measuring the decrease in the plasmon resonance band of the AuNPs at 527 nm after 9 min. The effect of reaction variables on the reaction sensitivity was investigated and furthermore, the interference of common ions was effectively avoided. The calibration curve is linear over the concentration range 3.3 × 10 À7 to 3.3 × 10 À6 mol/L of malathion with good precision and accuracy and the detection limit was down to 1.5 × 10 À7 mol/L. The developed approach does not use complex and expensive instruments. The high sensitivity of the proposed method allowed its successful application to wheat and water samples. Thus, the proposed strategy can serve as a powerful method for the rapid diagnosis of malathion in agriculture products.

Sensors and Actuators B: Chemical, 2014

This work reported the facile fabrication of a silver nanoparticle (AgNP)/graphene oxide (GO)-bas... more This work reported the facile fabrication of a silver nanoparticle (AgNP)/graphene oxide (GO)-based nanocomposite with glucose as a reducing and stabilization agent using an eco-friendly and low-cost method. The synthetic process could be conveniently employed in the fabrication of a disposable electrochemical sensor using a glassy carbon electrode (GCE). Based on the experimental results, this nanocomposite displayed the integrated properties of graphene and silver nanoparticles, which significantly promoted its electrocatalytic behavior. The electrochemical features of the AgNPs/GO/GCE with the tumor-supplied group of factors (TSGF) was evaluated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Compared with the GO film, the AgNPs/GO film displayed an obviously higher activity for TSGF electro-oxidation with a tenfold enhancement in the peak current. Under the selected test conditions, the oxidation peak currents were found to be proportional to the concentration of TSGF within the ranges of 0.01 μM-50.0 μM and 50.0 μM-800.0 μM. The developed sensor was used for the detection of TSGF in real specimens and showed desirable recoveries in the range of 98.18%-102.52%.

Química Nova, 2014

In this study, a procedure is developed for cloud point extraction of Pd(II) and Rh(III) ions in ... more In this study, a procedure is developed for cloud point extraction of Pd(II) and Rh(III) ions in aqueous solution using Span 80 (nonionic surfactant) prior to their determination by flame atomic absorption spectroscopy. This method is based on the extraction of Pd(II) and Rh(III) ions at a pH of 10 using Span 80 with no chelating agent. We investigated the effect of various parameters on the recovery of the analyte ions, including pH, equilibration temperature and time, concentration of Span 80, and ionic strength. Under the best experimental conditions, the limits of detection based on 3S b for Pd(II) and Rh(III) ions were 1.3 and 1.2 ng mL −1 , respectively. Seven replicate determinations of a mixture of 0.5 µg mL −1 palladium and rhodium ions gave a mean absorbance of 0.058 and 0.053 with relative standard deviations of 1.8 and 1.6%, respectively. The developed method was successfully applied to the extraction and determination of the palladium and rhodium ions in road dust and standard samples and satisfactory results were obtained.

RSC Advances, 2012

COF-1 was prepared using 250 mg of 1,4-benzene diboronic acid (BDBA, Aldrich) in 40 mL of a 1:1 v... more COF-1 was prepared using 250 mg of 1,4-benzene diboronic acid (BDBA, Aldrich) in 40 mL of a 1:1 v:v solution mixture of mesitylene (Aldrich) and 1,4-dioxane (Aldrich). The substrate mixture was introduced to a custom-made horn type Pyrex reactor, which was then fitted to a sonicator unit (VCX500, SONICS, USA) with an adjustable power output (maximum 500 W at 20 kHz). The reaction mixture was subjected to an ultrasonic treatment for 1 h. A white solid at bottom of the tube was isolated by centrifugation, washed with acetone (2×50 mL×10) and dried overnight at 353 K. 2. Synthesis of COF-5 As a standard synthesis, COF-5 was prepared using 177 mg of BDBA and 242 mg of 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP, TCI) in 40 mL of a 1:1 v:v solution mixture of mesitylene and 1,4-dioxane. The synthesis mixture was subjected to an ultrasonic treatment for 0.5 to 2 h at various power levels (40, 50, and 100%). A gray-purple solid powder at the bottom of the reactor was isolated by centrifugation, washed with acetone (2×50 mL×10) and dried at 353 K overnight.

RSC Adv., 2014

ABSTRACT Toluene–water interface has traditionally been employed to prepare particle assemblies a... more ABSTRACT Toluene–water interface has traditionally been employed to prepare particle assemblies and films of metals and semiconductors. The interface between water and an organic liquid, however, has not been investigated sufficiently for possible use in preparing nanocrystals and thin films of magnetic alloys. In this article, we demonstrate the use of liquid–liquid interface as a medium for preparing ultrathin films of magnetic Pt/Fe/Fe2O3 nanohybrid catalyst for methanol electrooxidation in NaOH medium. The resulting Pt/Fe/Fe2O3 hybrid catalyst shows the highest activity and CO tolerance (jf/jb = 8.09) among all other catalysts that tested up to now toward methanol electrooxidation. The results reported in this article demonstrate the versatility and potential of the liquid–liquid interface for preparing nanomaterials and ultrathin films and encourage further research in this area.

Water Science & Technology, 2014

A simple and sensitive adsorptive stripping voltammetry method was developed for determination of... more A simple and sensitive adsorptive stripping voltammetry method was developed for determination of Zn using N-nitrozo-N-phenylhydroxylamine (cupferron) as a selective complexing agent. This complex absorbed on the hanging mercury drop electrode and created a sensitive peak current. The peak current and concentration of zinc accorded with a linear relationship in the range of 0.85–320 ng mL−1. The influence of pH and the nature of supporting electrolytes, concentration of ligand, preconcentration time and applied potential were investigated. The relative standard deviation at a concentration level of 50 ng mL−1 was 1.8%. The method was applied to the determination of zinc in city, river and mineral water samples, with satisfactory results.

Microchimica Acta, 2011

An electrochemical method is presented for the preparation of sulfur nanoparticles (S-NPs) from t... more An electrochemical method is presented for the preparation of sulfur nanoparticles (S-NPs) from thiosulfate ion. The particle size of the S-NPs can be adjusted between 35 and 65 nm by varying parameters such as the initial concentration of thiosulfate. The solvent/non-solvent precipitation method was also applied to the preparation of S-NPs for comparison. In this case, the use of hot alcohol and cold water as solvent/non-solvent system along with 100 ml•min −1 flow rate for co-mixing of non-solvent resulted in the formation of S-NPs in a typical size of 250 nm that are fairly homogeneous in shape and have a narrow particle size distribution. The results revealed that, in comparison to the precipitation process, the electrosynthetic method offers simplicity, higher efficiency, improved size control, and less environmental contamination.

Journal of the Iranian Chemical Society, 2011

Nanocrystals provide a confinement effect for nanoscale engineering. In this work the cadmium sel... more Nanocrystals provide a confinement effect for nanoscale engineering. In this work the cadmium selenide quantum dot and its nanoparticle films have been deposited by chemical bath deposition method (CBD). Effects of deposition time, pH and annealing operation on the optical and structural of CdSe nanoparticle film were studied. The energy band gap, structure and morphology of the samples are investigated by X-ray diffraction (XRD), UV-Vis spectrometer and scanning electron microscope (SEM). It was found that the optical band gap, nanoparticle size and thin film configuration are changed by varying pH, deposition time and annealing operation.