Publications by authors named "Tayyebeh Madrakian"

87 Publications

Preparation and characterization of γ-FeO nanoparticles and investigation of its adsorption performance for sulfide, sulfite and thiosulfate from aqueous solutions using ultrasonic assisted method: Modeling and optimization.

Ultrason Sonochem 2018 Jan 30;40(Pt A):1049-1058. Epub 2017 Aug 30.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

Maghemite nanoparticles, as an adsorbent, was used for the removal of sulfur species including sulfide, sulfite and thiosulfate from waste water samples by ultrasonic-assisted adsorption method. The characterization of the prepared nanoparticles was carried out by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and BET technique. The nanoparticles well dispersed in the water. The adsorbent was easily separated magnetically from the solution after loading with adsorbate. According to central composite design, the best experimental conditions including initial pH, the dosage of adsorbent and sonication time were obtained for sulfide, sulfite and thiosulfate. After optimization of the parameters, the removal of analytes in these conditions lead to the highest analytes removal efficiency (above 98%). The adsorption capacity was evaluated using different adsorption isotherm models. The maximum predicted adsorption capacities for sulfide, sulfite and thiosulfate were obtained as 148.5, 122.5 and 119.6mgg, respectively. Then, desorption process of the adsorbed thiosulfate was also investigated using sodium hydroxide solution as the solvent and the other conditions affect to desorption were optimized.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ultsonch.2017.08.035DOI Listing
January 2018

Graphene nanoribbon/FePt bimetallic nanoparticles/uric acid as a novel magnetic sensing layer of screen printed electrode for sensitive determination of ampyra.

Talanta 2018 Jan 16;176:350-359. Epub 2017 Aug 16.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A novel electrochemical sensor for sensitive determination of ampyra (Am) based on graphene nanoribbons modified by iron-platinum bimetallic nanoparticles and uric acid (SPCE/FePtGNR/UA) dropped on the screen-printed carbon electrode (SPCE) surface and magnetically captured onto an SPCE working electrode surface is reported in the present work. The modified nanocomposite and sensing layer was characterized by different techniques, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray powdered diffraction (XRD). Am determination by conventional electrochemical methods is not possible, because of its high redox overpotential. Therefore, the differential pulse voltammetry (DPV) signals of UA were used as a redox probe for indirect electrochemical determination of Am. The limit of detection (LOD) and linear concentration range were obtained as 0.028 and 0.08-9.0µmolL (3S/m = 3), respectively. The feasibility of the proposed method was examined by the detection of Am in biological and pharmaceutical samples with satisfactory results. The constructed electrochemical sensor was applied for fast, simple and sensitive detection of Am in real environments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2017.08.046DOI Listing
January 2018

Fabrication of a novel impedimetric sensor based on l-Cysteine/Cu(II) modified gold electrode for sensitive determination of ampyra.

Anal Chim Acta 2017 Sep 30;984:185-192. Epub 2017 Jun 30.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

This paper presents a novel impedimetric sensor for the sensitive determination of ampyra (Am) based on the l-Cysteine/Cu (II) modified gold electrode (Cu (II)/L-Cys/AuE). This novel sensing layer was characterized by different techniques, including atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Am determination by conventional electrochemical methods is not possible, because of its high redox overpotential. Therefore, [Fe(CN)] was used as a redox probe for the impedimetric determination of Am. Under the optimized conditions, the calibration curve for Am concentration was linear in the range 0.010-40.0 nM with a detection limit of 0.0028 nM. The practical applicability of the proposed sensor was examined by evaluating the detection of Am in biological fluids and pharmaceutical samples with satisfied recoveries. Therefore, the prepared sensor can hold great promise for fast, simple and sensitive detection of Am in various real samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2017.06.038DOI Listing
September 2017

A label-free electrochemical biosensor based on tubulin immobilized on gold nanoparticle/glassy carbon electrode for the determination of vinblastine.

Anal Bioanal Chem 2017 Sep 30;409(22):5269-5278. Epub 2017 Jun 30.

Department of Production of Medical Plant, Nahavand University, Nahavand, 6591913989, Iran.

Vinblastine (VLB) is prescribed for a wide variety of cancers. Therefore, development of sensitive methods for early diagnosis is urgently required. In this work, a highly sensitive and label-free impedimetric biosensor was fabricated for the electrochemical detection of VLB. First, the gold nanoparticles (AuNPs) were electrodeposited on the surface of a glassy carbon electrode (GCE). 3-Mercaptopropionic acid (MPA) was self-assembled over the AuNPs. Then, tubulin (TUB), as a receptor, was covalently immobilized at the AuNPs/GCE surface via carbodiimide coupling reaction using N-(3 dimethylaminopropyl)-N'-ethyl carbodiimide (EDC) and N-hydroxy succinimide (NHS). The step-by-step modification process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of a redox probe [Fe(CN)]. The VLB concentration was measured through the increase of impedance values in the corresponding specific binding of VLB and TUB. The increased electron-transfer resistance (R ) values were proportional to the value of VLB concentrations in the range of 0.4 to 65.0 nmol L with a detection limit of 8.4 × 10 nmol L (SN = 3). The practical analytical performance of the proposed method was demonstrated by determination of VLB in plant extracts and human serum samples with satisfactory recoveries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00216-017-0471-yDOI Listing
September 2017

Magnetic headspace adsorptive extraction of chlorobenzenes prior to thermal desorption gas chromatography-mass spectrometry.

Anal Chim Acta 2017 Jun 10;971:40-47. Epub 2017 Apr 10.

Department of Analytical Chemistry, Nutrition and Food Sciences and University Institute of Materials, University of Alicante, P.O. Box 99, E-03080, Alicante, Spain. Electronic address:

This study presents a new, user-friendly, cost-effective and portable headspace solid-phase extraction technique based on graphene oxide decorated with iron oxide magnetic nanoparticles as sorbent, located on one end of a small neodymium magnet. Hence, the new headspace solid-phase extraction technique has been called Magnetic Headspace Adsorptive Extraction (Mag-HSAE). In order to assess Mag-HSAE technique applicability to model analytes, some chlorobenzenes were extracted from water samples prior to gas chromatography-mass spectrometry determination. A multivariate approach was employed to optimize the experimental parameters affecting Mag-HSAE. The method was evaluated under optimized extraction conditions (i.e., sample volume, 20 mL; extraction time, 30 min; sorbent amount, 10 mg; stirring speed, 1500 rpm, and ionic strength, non-significant), obtaining a linear response from 0.5 to 100 ng L for 1,3-DCB, 1,4-DCB, 1,2-DCB, 1,3,5-TCB, 1,2,4-TCB and 1,2,3-TCB; from 0.5 to 75 ng L for 1,2,4,5-TeCB, and PeCB; and from 1 to 75 ng L for 1,2,3,4-TeCB. The repeatability of the proposed method was evaluated at 10 ng L and 50 ng L spiking levels, and coefficients of variation ranged between 1.5 and 9.5% (n = 5). Limits of detection values were found between 93 and 301 pg L. Finally, tap, mineral and effluent water were selected as real water samples to assess method applicability. Relative recoveries varied between 86 and 110% showing negligible matrix effects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2017.04.002DOI Listing
June 2017

Application of nickel zinc ferrite/graphene nanocomposite as a modifier for fabrication of a sensitive electrochemical sensor for determination of omeprazole in real samples.

J Colloid Interface Sci 2017 06 2;495:1-8. Epub 2017 Feb 2.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

In the present study, a simple and highly sensitive sensor for the determination of omeprazole based on nickel-zinc ferrite/graphene modified glassy carbon electrode is reported. The morphology and electro analytical performance of the fabricated sensor were characterized with X-ray diffraction spectrometry, Fourier transform infrared spectrometry, scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry, differential pulse voltammetry and operation of the sensor. Results were compared with those achieved at the graphene modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions, linear response was over the range of 0.03-100.0µmolL. The lower detection limit was found to be 0.015µmolL. The effect of different interferences on the anodic current response of OMZ was investigated. By measuring the concentrations of omeprazole in plasma and pharmaceutical samples, the practical application of the modified electrode was evaluated. This revealed that the nickel-zinc ferrite/graphene modified glassy carbon electrode shows excellent analytical performance for the determination of omeprazole with a very low detection limit, high sensitivity, and very good accuracy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2017.01.116DOI Listing
June 2017

Nanomaterials as sorbents for sample preparation in bioanalysis: A review.

Anal Chim Acta 2017 03 7;958:1-21. Epub 2016 Dec 7.

Department of Environmental and Analytical Chemistry, Stockholm University, SE10691 Stockholm, Sweden. Electronic address:

In recent years, application of nanomaterials as sorbent has gained the attention of researchers in bioanalysis. Different nanomaterials have been utilized as the sorbent in extraction techniques such as solid phase extraction, dispersive solid phase extraction, magnetic solid phase extraction, microextraction by packed sorbent, solid phase microextraction, dispersive μ-solid phase extraction, and stir bar sorptive extraction. In the present review, different nanomaterials which have recently been utilized as sorbent for bioanalysis are classified into six main groups, namely metallic, metallic and mixed oxide, magnetic, carbonaceous, silicon, and polymer-based nanomaterials. Application of these nanomaterials in different extraction techniques for bioanalysis has been reviewed. This study shows that magnetic nanomaterials have gained significant attention owing to their magnetic separation ability. In addition, the present review shows that there is a lack in the application of nanomaterials for on-line analysis procedures, most probably due to some intrinsic properties of nanomaterials such as spontaneous agglomeration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2016.11.062DOI Listing
March 2017

Determination of ᴅ-phenylglycine in the presence of its ʟ-enantiomer using a turn-on fluorescent nano-chemosensor.

Talanta 2017 Jan 13;162:547-551. Epub 2016 Oct 13.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

This paper reports on application of ʟ-tryptophan modified magnetite nanospheres (TryMNSs) as a novel fluorescent chiral selector for selective and sensitive determination of ᴅ-phenylglycine (ᴅ-Phy) in the presence of its enantiomer (i.e. ʟ-phenylglycine, ʟ-Phy). The results showed that the nanospheres could be used as a "turn-on" fluorescence nanosensor based on enhancement of its fluorescence peak intensity in the presence of ᴅ-Phy. Unlike its enantiomer, ʟ-Phy did not affect the nanosensor fluorescence behaviour suggesting that using the synthesized nanospheres selective determination of ᴅ-Phy in the presence of ʟ-Phy was achievable. The enhancing effect can be attributed to the initial formation of hydrogen-bonded complex followed by π-π interaction between the aromatic tryptophan moieties and ᴅ-Phy. After various affecting factors optimizing, the results showed that using the enhancing effect, selective and sensitive determination of ᴅ-Phy in the presence of ʟ-Phy in the concentration range of 0.5-200.0mgL with a detection limit as low as 190ngmL was achievable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2016.10.054DOI Listing
January 2017

Impedimetric immunosensor for the label-free and direct detection of botulinum neurotoxin serotype A using Au nanoparticles/graphene-chitosan composite.

Biosens Bioelectron 2017 Jul 18;93:124-131. Epub 2016 Sep 18.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

In this work, a novel nanocomposite film consisting of the Au nanoparticles/graphene-chitosan has been designed to construct an impedimetric immunosensor for a rapid and sensitive immunoassay of botulinum neurotoxin A (BoNT/A). BoNT/A antibody was immobilized on glassy carbon electrode modified with Au nanoparticles/graphene-chitosan for the signal amplification. The fabrication of immunosensor was extensively characterized by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The impedance changes, due to the specific immuno-interactions at the immunosensor surface that efficiently restricted the electron transfer of redox probe Fe(CN) were utilized to detect BoNT/A. The measurements were highly targeted specific and linear with logarithmic BoNT/A concentrations in PBS, milk and human serum across a 0.27-268pgmL range and associated with a detection limit of 0.11pgmL.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2016.09.059DOI Listing
July 2017

An electrochemical sensor for rizatriptan benzoate determination using Fe3O4 nanoparticle/multiwall carbon nanotube-modified glassy carbon electrode in real samples.

Mater Sci Eng C Mater Biol Appl 2016 Jun 16;63:637-43. Epub 2016 Mar 16.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

In this paper a sensitive and selective electrochemical sensor for determination of rizatriptan benzoate (RZB) was proposed. A glassy carbon electrode was modified with nanocomposite of multiwalled carbon nanotubes (MWCNTs) and Fe3O4 nanoparticles (Fe3O4/MWCNTs/GCE). The results obtained clearly show that the combination of MWCNTs and Fe3O4 nanoparticles definitely improves the sensitivity of modified electrode to RZB determination. The morphology and electroanalytical performance of the fabricated sensor were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), square wave voltammetry (SWV) and cyclic voltammetry (CV). Also, the effect of experimental and instrumental parameters on the sensor response was evaluated. The square wave voltammetric response of the electrode to RZB was linear in the range 0.5-100.0 μmol L(-1) with a detection limit of 0.09 μmol L(-1) under the optimum conditions. The investigated method showed good stability, reproducibility and repeatability. The proposed sensor was successfully applied for real life samples of blood serum and RZB determination in pharmaceutical.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2016.03.041DOI Listing
June 2016

Electrochemically oxidized multiwalled carbon nanotube/glassy carbon electrode as a probe for simultaneous determination of dopamine and doxorubicin in biological samples.

Anal Bioanal Chem 2016 Apr 12;408(10):2577-86. Epub 2016 Feb 12.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, 65174, Iran.

A facile and effective approach of fabricating oxidized multiwalled carbon nanotube/glassy carbon electrode (OMWCNT/GCE) is herein reported. The OMWCNT/GCE was prepared by electrochemical oxidation method in basic media (0.5 mol L(-1) NaOH solution) and used as a sensor for simultaneous determination of dopamine (DA) and doxorubicin (DOX). Scanning electron microscopy, energy dispersive X-ray spectroscopy and cyclic voltammetry were used for characterization and performance study of the OMWCNT/GCE. The modified electrode exhibited good electrocatalytic properties toward the oxidation of DA and DOX. Peaks potential difference of 240 mV between DA and DOX was large enough to determine DA and DOX individually and simultaneously. Square wave voltammetry (SWV) was used for the simultaneous determination of DA and DOX in their binary mixture. Under the optimum conditions, the linear concentration dependences of SW peak current responses were observed for DA and DOX in the concentration ranges of 0.03-55 μmol L(-1) and 0.04-90 μmol L(-1), respectively. The detection limits (S/N = 3) were 8.5 × 10(-3) μmol L(-1), and 9.4 × 10(-3) μmol L(-1) for DA and DOX, respectively. The analytical utility of OMWCNT/GCE was also successfully demonstrated for the simultaneous determination of DA and DOX in human blood serum and urine samples. Graphical Abstract Fabrication of new oxidized multiwalled carbon nanotube/glassy carbon electrode for simultaneous determination of dopamine and doxorubicin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00216-016-9361-yDOI Listing
April 2016

Solid phase extraction of amoxicillin using dibenzo-18-crown-6 modified magnetic-multiwalled carbon nanotubes prior to its spectrophotometric determination.

Talanta 2016 22;148:122-8. Epub 2015 Oct 22.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

This work reports on a method for selective extraction and sensitive determination of amoxicillin drug (AMX). The method is based on solid phase extraction of AMX by a novel modified magnetic nanoadsorbent prior to spectrophotometric determination of AMX using a procedure based on formation a colored azo-derivative of the investigated drug. The nanoadsorbent has been synthesized by modification of magnetic-multiwalled carbon nanotube with dibenzo-18-crown-6 moieties. The synthesized nanoparticles were characterized using TEM, XRD and FT-IR measurements. At the next step, various factors that could potentially affect adsorption and desorption efficiencies of AMX, have been optimized. The results showed that under the optimized conditions, sensitive and selective determination of the investigated drug in concentration range of 5.0-1000.0 ng mL(-1) with the limit of detection of 3.0 ng mL(-1) was achievable. Furthermore, the real sample analysis (i.e. amoxicillin capsules and human urine samples) results indicated that a reliable promising candidate method has been developed for the determination of AMX in the investigated real samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2015.10.051DOI Listing
September 2016

Construction of novel sensitive electrochemical sensor for electro-oxidation and determination of citalopram based on zinc oxide nanoparticles and multi-walled carbon nanotubes.

Mater Sci Eng C Mater Biol Appl 2016 Feb 30;59:847-854. Epub 2015 Oct 30.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A new chemically modified carbon paste electrode (CMCPE) was applied to the simple, rapid, highly selective and sensitive determination of citalopram in human serum and pharmaceutical preparations using adsorptive square wave voltammetry (ASWV). The ZnO nanoparticles and multi-walled carbon nanotubes modified CPE (ZnO-MWCNT/CPE) electrode was prepared by incorporation of the ZnO nanoparticles and multi-walled carbon nanotubes (MWCNT) in carbon paste electrode. The limit of detection and the linear range were found to be 0.005 and 0.012 to 1.54μmolL(-1) of citalopram, respectively. The effects of potentially interfering substances on the determination of this compound were investigated and found that the electrode is highly selective. The proposed CMCPE was used to the determination of citalopram in human serum, urine and pharmaceutical samples. This reveals that ZnO-MWCNT/CPE shows excellent analytical performance for the determination of citalopram in terms of very low detection limit, high sensitivity, very good repeatability and reproducibility over other methods reported in the literature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2015.10.088DOI Listing
February 2016

Gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode as a sensitive voltammetric sensor for the determination of diclofenac sodium.

Mater Sci Eng C Mater Biol Appl 2016 Feb 3;59:168-176. Epub 2015 Oct 3.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A simple and highly sensitive sensor for the determination of diclofenac sodium based on gold nanoparticle/multi-walled carbon nanotube modified glassy carbon electrode is reported. Scanning electron microscopy along with energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry was used to characterize the nanostructure and performance of the sensor and the results were compared with those obtained at the multi-walled carbon nanotube modified glassy carbon electrode and bare glassy carbon electrode. Under the optimized experimental conditions diclofenac sodium gave linear response over the range of 0.03-200μmolL(-1). The lower detection limits were found to be 0.02μmolL(-1). The effect of common interferences on the current response of DS was investigated. The practical application of the modified electrode was demonstrated by measuring the concentration of diclofenac sodium in urine and pharmaceutical samples. This revealed that the gold nanoparticle/multiwalled carbon nanotube modified glassy carbon electrode shows excellent analytical performance for the determination of diclofenac sodium in terms of a very low detection limit, high sensitivity, very good accuracy, repeatability and reproducibility.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2015.09.097DOI Listing
February 2016

A novel electrochemical sensor based on magneto Au nanoparticles/carbon paste electrode for voltammetric determination of acetaminophen in real samples.

Mater Sci Eng C Mater Biol Appl 2015 Dec 31;57:205-14. Epub 2015 Jul 31.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

An electrochemical magneto Au nanoparticles/carbon paste electrodes (MAuNP/CPE) which is used for the determination of acetaminophen (AC) in real samples was developed. Initially, Au nanoparticles were immobilized at the surface of Fe3O4 ([email protected]), which was used as a sorbent for capturing AC molecules. After adding [email protected] to the AC solution and stirring for 20 min, the [email protected] was gathered on the magneto electrode based on its magnetic field. The AC molecules which became adsorbed at [email protected] were analyzed by differential pulse voltammetry (DPV). For characterization and investigation of the performance of [email protected] and MAuNPs/CPE, various methods, including scanning electron microscopy, X-ray diffraction, UV-Vis spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and DPV were used. Under the optimized conditions, the anodic peak current was linear to the concentration of AC in the range of 0.1 to 70.0μmol L(-1) with the detection limit of 4.5×10(-2)μmol L(-1). This method was also successfully used to detect the concentration of AC in pharmaceutical formulations and human serum samples. In addition, the proposed magneto sensor exhibited good reproducibility, long-term stability and fast current response.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2015.07.054DOI Listing
December 2015

Construction a magneto carbon paste electrode using synthesized molecularly imprinted magnetic nanospheres for selective and sensitive determination of mefenamic acid in some real samples.

Biosens Bioelectron 2015 Jun 3;68:712-718. Epub 2015 Feb 3.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A novel magneto multiwalled carbon nanotube/carbon paste electrode (MMW/CPE) for the determination of mefenamic acid (MFA) was introduced. Magnetic molecularly imprinted polymer nanoparticles (MMIPNPs) were synthesized and then added to the solution of MFA. After stirring for 20 min, the MMW/CPE was immersed in the solution of MFA (contain MMIPNPs) and the MMIPNPs were captured by it. Then oxidation of MFA was analyzed by differential pulse voltammetry (DPV). Electrochemical impedance spectroscopy, cyclic voltammetry, and DPV were employed to characterize the MMW/CPE. The MMIPNPs exhibited a high selectivity and sensitivity toward MFA. The effect of various experimental parameters including pH, MMIPNPs dosage, stirring time, accumulation potential and time on the voltammetric response of MFA were investigated. Under the optimal conditions, selective detection of MFA in a linear concentration range of 2.0-1000.0 nmol L(-1) was performed with the detection limit of 1.2 nmol L(-1) (3S/N). To further study the practical applicability of this method, it was applied to the analysis of some real samples and the obtained results were satisfactory.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2015.02.001DOI Listing
June 2015

Molecularly imprinted polymer coated magnetite nanoparticles as an efficient mefenamic acid resonance light scattering nanosensor.

Anal Chim Acta 2014 Dec 26;852:250-6. Epub 2014 Sep 26.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

In this work, a mefenamic acid (MFA) nanosensor was synthesized by the aid of molecularly imprinted polymer (MIP) technique. MIP layer was coated on magnetite nanoparticles as magnetic nano-carriers. Synthesized nanoparticles were characterized using various measurements techniques. Light scattering properties of the synthesized nanoparticles in the presence or absence of MFA have been selected as the detection signal. In this regard, resonance light scattering has been used as the detection method. Various factors that can potentially affect light scattering efficiency (i.e., pH, ultrasonication time and nanoparticle dosage) were optimized using "one-at-a-time" method. A linear dynamic range was established from 100.0 to 2000.0 ng L(-1) of MFA and the limit of detection was found to be 50.0 ng L(-1) using the proposed method.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2014.09.039DOI Listing
December 2014

Determination of human albumin in serum and urine samples by constant-energy synchronous fluorescence method.

Luminescence 2015 Aug 6;30(5):576-82. Epub 2014 Nov 6.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A sensitive spectrofluorimetric method using constant-energy synchronous fluorescence technique is proposed for the determination of human albumin without separation. In this method, no reagent was used for enhancement of the fluorescence signal of albumin in the solution. Effects of some parameters, such as energy difference between excitation and emission monochromators (ΔE), emission and excitation slit widths and scan rate of wavelength were studied and the optimum conditions were established. For this purpose factorial design and response surface method were employed for optimization of the effective parameters on the fluorescence signal. The results showed that the scan rate of the wavelength has no significant effect on the analytical signal. The calibration curve was linear in the range 0.1-220.0 µg mL(-1) of albumin with a detection limit of 7.0 × 10(-3)  µg mL(-1). The relative standard deviations (RSD) for six replicate measurements of albumin were calculated as 2.2%, 1.7% and 1.3% for 0.5, 10.0 and 100.0 µg mL(-1) albumin, respectively. Furthermore the proposed method has been employed for the determination of albumin in human serum and urine samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/bio.2788DOI Listing
August 2015

New nano-composite potentiometric sensor composed of graphene nanosheets/thionine/molecular wire for nanomolar detection of silver ion in various real samples.

Talanta 2015 Jan 20;131:548-55. Epub 2014 Aug 20.

Chemical Injuries Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.

A novel nanographene carbon composite potentiometric sensor for the determination of trace amounts of silver(I) ion was fabricated. Its sensing layer was prepared with the addition of graphene nanosheets into the matrix consisting of graphite powder, diphenylacetylene "a typically molecular wire (MW) as the conductive binder" and thionine as an efficient ionophore. For investigation of the ion-to-electron transducing ability of graphene nanosheets and molecular wire on the electrode surface, the electrochemical impedance spectroscopy measurements were done and the morphology and properties of the electrode surfaces were characterized by scanning electron microscopy. Under the optimized experimental conditions, the suggested potentiometric silver(I) sensor exhibited an excellent Nernstian slope of 59.70 mV decade(-1) with a rapid response to silver(I) ion within ~ 6s. The response was linear in the range 8.00 × 10(-9) to 1.00 × 10(-2) mol L(-1) and calculated detection limit was 4.17 × 10(-9) mol L(-1). The suggested sensor was successfully applied to the determination of silver in radiological film, environmental and drug samples with satisfactory results.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2014.08.004DOI Listing
January 2015

Simultaneous determination of mycophenolate mofetil and its active metabolite, mycophenolic acid, by differential pulse voltammetry using multi-walled carbon nanotubes modified glassy carbon electrode.

Mater Sci Eng C Mater Biol Appl 2014 Sep 15;42:38-45. Epub 2014 May 15.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A highly sensitive electrochemical sensor for the simultaneous determination of mycophenolate mofetil (MPM) and mycophenolic acid (MPA) was fabricated by multi-walled carbon nanotubes modified glassy carbon electrode (MWCNTs/GCE). The electrochemical behavior of these two drugs was studied at the modified electrode using cyclic voltammetry and adsorptive differential pulse voltammetry. MPM and MPA were oxidized at the GCE during an irreversible process. DPV analysis showed two oxidation peaks at 0.87V and 1.1V vs. Ag/AgCl for MPM and an oxidation peak at 0.87V vs. Ag/AgCl for MPA in phosphate buffer solution of pH5.0. The MWCNTs/GCE displayed excellent electrochemical activities toward oxidation of MPM and MPA relative to the bare GCE. The experimental design algorithm was used for optimization of DPV parameters. The electrode represents linear responses in the range 5.0×10(-6) to 1.6×10(-4)molL(-1) and 2.5×10(-6)molL(-1) to 6.0×10(-5)molL(-1) for MPM and MPA, respectively. The detection limit was found to be 9.0×10(-7)molL(-1) and 4.0×10(-7)molL(-1) for MPM and MPA, respectively. The modified electrode showed a good sensitivity and stability. It was successfully applied to the simultaneous determination of MPM and MPA in plasma and urine samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2014.05.012DOI Listing
September 2014

A sensitive electrochemical sensor for rapid determination of methadone in biological fluids using carbon paste electrode modified with gold nanofilm.

Talanta 2014 Oct 17;128:203-10. Epub 2014 Mar 17.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A novel and effective electrochemical sensor for the determination of methadone (MET) at pH 9.0 using gold nanoparticles, electrodeposited on a multi-walled carbon nanotube modified carbon paste electrode (GNPs/MWCPE), is introduced. The voltammetric behavior of MET at this modified electrode was studied using cyclic and square wave voltammetric techniques and the results were compared with those obtained at the multi-walled carbon nanotube modified carbon paste electrode (MWCPE). The oxidation of MET was irreversible and exhibited an adsorption controlled process at the GNPs/MWCPE and a diffusion controlled process at the MWCPE. The effect of various experimental parameters including pH, scan rate, and accumulation potential and time on the voltammetric response of MET was investigated. At the optimum conditions, the concentration of MET was determined using square wave voltammetry (SWV) in a linear range of 0.1-500.0 µmol L(-1) with a correlation coefficient of 0.9901 at the GNPs/MWCPE, and 0.5-300.0 µmol L(-1) with a correlation coefficient of 0.993 at the MWCPE and the detection limits were found to be 0.005 and 0.3 µmol L(-1), respectively. The proposed electrode was successfully applied to the determination of MET in a pharmaceutical dosage form, urine and saliva samples. The effects of common interferences, namely some of different cations and anions, on the current response of MET were investigated. This revealed that the GNPs/MWCPE shows excellent analytical performance for the determination of MET in terms of a very low detection limit, high sensitivity, very good repeatability and reproducibility.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2014.03.003DOI Listing
October 2014

Preparation of NiFe₂O₄/graphene nanocomposite and its application as a modifier for the fabrication of an electrochemical sensor for the simultaneous determination of tramadol and acetaminophen.

Anal Chim Acta 2014 Jun 2;831:50-9. Epub 2014 May 2.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

An effective electrochemical sensor for the rapid and simultaneous determination of tramadol and acetaminophen based on carbon paste electrode (CPE) modified with NiFe2O4/graphene nanoparticles was developed. The structures of the synthesized NiFe2O4/graphene nanocomposite and the electrode composition were confirmed by X-ray diffraction (XRD) spectrometry, Fourier transform infrared (FT-IR) spectrometry and scanning electron microscopy (SEM). The peak currents of square wave voltammetry of tramadol and acetaminophen increased linearly with their concentration in the range of 0.01-9 μmol L(-1). The detection limit for their determination was found to be 0.0036 and 0.0030 μmol L(-1), respectively. The results show that the combination of graphene and NiFe2O4 nanoparticles causes a dramatic enhancement in the sensitivity of the sensor. The fabricated sensor exhibited high sensitivity and good stability, and would be valuable for the clinical assay of tramadol and acetaminophen.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2014.04.061DOI Listing
June 2014

Electro-oxidation and voltammetric determination of oxymetholone in the presence of mestanolone using glassy carbon electrode modified with carbon nanotubes.

Talanta 2014 Apr 30;121:1-8. Epub 2013 Dec 30.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A new chemically modified electrode was constructed and applied to the electro-oxidation of the oxymetholone. Also, the electrode was applied to the simple, rapid, highly selective and sensitive determination of oxymetholone (OXM) in pharmaceutical and plasma samples using square wave voltammetry (SWV). The multi-walled carbon nanotubes modified glassy carbon electrode (MWCNT/GCE) were prepared by casting of the multi-walled carbon nanotubes (MWCNT) suspension on the glassy carbon electrode surface. The limit of detection and the linear range were found to be 1.36 and 2.00-90.00 ng mL(-1) of OXM, respectively. The effects of potentially interfering substances on the determination of this compound were investigated and found that the electrode is highly selective. The proposed modified electrode was used for the determination of OXM in human plasma and pharmaceutical samples. This reveals that MWCNT/GCE shows excellent analytical performance for the determination of OXM in terms of very low detection limit, high sensitivity, very good repeatability and reproducibility over other methods reported in literature.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2013.12.047DOI Listing
April 2014

Construction of a carbon ionic liquid paste electrode based on multi-walled carbon nanotubes-synthesized Schiff base composite for trace electrochemical detection of cadmium.

Mater Sci Eng C Mater Biol Appl 2014 Feb 31;35:8-14. Epub 2013 Oct 31.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A simple, highly sensitive and selective carbon nanocomposite electrode has been developed for the electrochemical trace determination of cadmium. This sensor was designed by incorporation of multi-walled carbon nanotubes (MWCNTs) and a new synthesized Schiff base into the carbon paste ionic liquid electrode (CPE(IL)) which provides remarkably improved sensitivity and selectivity for the electrochemical stripping assay of Cd(II). The detection limit of the method was found to be 0.08 μg L(-1) (S/N=3) that is lower than the maximum contaminant level of Cd(II) allowed by the Environmental Protection Agency (EPA) in standard drinking waters. The proposed electrode exhibits good applicability for monitoring Cd(II) in various real samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2013.10.025DOI Listing
February 2014

Preconcentration and spectrophotometric determination of oxymetholone in the presence of its main metabolite (mestanolone) using modified maghemite nanoparticles in urine sample.

Talanta 2013 Oct 11;115:468-73. Epub 2013 Jun 11.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran. Electronic address:

A novel and sensitive extraction procedure using maghemite nanoparticles (γ-Fe2O3) modified with sodium dodecyl sulfate (SDS), as an efficient solid phase, was developed for removal, preconcentration and spectrophotometric determination of trace amounts of oxymetholone (OXM), in the presence of mestanolone (MSL). Combination of nanoparticle adsorption and easily magnetic separation was used for the extraction and desorption of OXM. The preparation of γ-Fe2O3 nanoparticles were obtained by co-precipitation method and their surfaces were modified by SDS. The size and properties of the produced γ-Fe2O3 nanoparticles were determined by X-ray diffraction analysis, FT-IR and scanning electron microscopy measurements. OXM and MSL became adsorbed at pH 3.0. The adsorbed drugs were then desorbed and determined spectrophotometrically using a selective complexation reaction for OXM. The calibration graph was linear in the range 15.0-3300.0 ng mL(-1) of OXM with a correlation coefficient of 0.9948. The detection limit of the method for determination of OXM was 4.0 ng mL(-1). The method was applied for the determination of OXM in human urine samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2013.05.056DOI Listing
October 2013

Surface decoration of multi-walled carbon nanotubes modified carbon paste electrode with gold nanoparticles for electro-oxidation and sensitive determination of nitrite.

Biosens Bioelectron 2014 Jan 16;51:379-85. Epub 2013 Aug 16.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran. Electronic address:

In this paper, a highly sensitive and selective voltammetric sensor for the determination of nitrite is proposed. We described a fast and easy method for the fabrication of gold nanoparticles/multi-walled carbon nanotube/carbon paste electrode (GNPs /MWCPE) by one-step electrodeposition under controlled potential, the whole procedure takes only several minutes. Scanning electron microscopy (SEM) image demonstrated that the gold nanoparticles deposited on MWCNTs/CPE were uniform, with an average size of 30 nm. By combining the benefits of GNPs/MWCNTs and CPE, the resulted modified electrode exhibited outstanding electrocatalytic activity in terms of nitrite oxidation by giving much higher peak currents than those found for the unmodified CPE and also the MWCNTs-modified electrode. The effect of various experimental parameters on the voltammetric response of nitrite was investigated. At the optimum conditions the sensor has a linear response in the 0.05-250.0 µmol L(-1) concentration range, a very good detection sensitivity (0.4177 μA L µmol(-1)), and a low detection limit of 1×10(-2) μmol L(-1) of nitrite. Most common ions and many environmental organic pollutants do not interfere. The proposed chemically modified electrode was used to the determination of NO2(-) in several foodstuffs and water samples and the results were found to be consistent with the values obtained by the Griess protocol.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2013.07.056DOI Listing
January 2014

Selective solid-phase extraction of naproxen drug from human urine samples using molecularly imprinted polymer-coated magnetic multi-walled carbon nanotubes prior to its spectrofluorometric determination.

Analyst 2013 Aug 6;138(16):4542-9. Epub 2013 Jun 6.

Faculty of Chemistry, Bu Ali Sina University, Hamedan, Iran.

A drug imprinted polymer based on suspension polymerization on magnetic multi-walled carbon nanotubes (MIPMCNTs) was prepared with a synthesized amidoamine as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, naproxen (NAP) as the template and ammonium persulfate as the initiator. The MIPMCNTs were characterized by TEM, FT-IR and XRD measurements. The prepared magnetic adsorbent can be well dispersed in aqueous media and can be easily separated magnetically from the medium after loading with NAP. All the aspects influencing the adsorption (extraction time, adsorbent dosage and pH) and desorption (desorption time and desorption solvent) of the analyte on the MIPMCNTs have been investigated. The extracted NAP could be easily desorbed with a mixture of methanol/sodium hydroxide aqueous solution and determined spectrofluorometrically at λem = 353 nm (λex = 271 nm). A linear dynamic range was established from 4.0 to 40.0 ng mL⁻¹ of NAP and the limit of detection (LOD) was found to be 2.0 ng mL⁻¹. In addition, the equilibrium adsorption data of NAP by imprinted polymer were analyzed by Langmuir and Freundlich isotherm models. The developed method was utilized for the determination of NAP in human urine samples with satisfactory results.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c3an00686gDOI Listing
August 2013

Superparamagnetic surface molecularly imprinted nanoparticles for sensitive solid-phase extraction of tramadol from urine samples.

Talanta 2013 Feb 31;105:255-61. Epub 2012 Dec 31.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A rapid, selective, sensitive and accurate method based on superparamagnetic molecularly imprinted polymer nanoparticles (MMIPNPs) was developed for the determination of tramadol (TRA) in human urine samples. The MMIPNPs were prepared by coating SiO2-Fe3O4 nanoparticles with polyaminoimide homopolymer and TRA as the template. The prepared MMIPNPs adsorbent was characterized by TEM, FT-IR, XRD and magnetometry. TEM images show that the Fe3O4 nanoparticles are well-enwrapped by the SiO2 shell and further by an MIP layer. The prepared magnetic adsorbent is well dispersed in water and can be easily separated magnetically from the medium after loading with the adsorbate. Various parameters affecting the extraction efficiency of the MMIPNPs have been evaluated. The extracted TRA could be easily desorbed with a mixture of methanol and acetic acid and determined spectrophotometrically at 272 nm. A linear dynamic range was established from 3.0 to 200.0 ng mL(-1) of TAR and the limit of detection was found to be 1.5 ng mL(-1). The proposed method was successfully applied for the determination of TRA in human urine samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2012.12.039DOI Listing
February 2013

Fabrication and application of a new modified electrochemical sensor using nano-silica and a newly synthesized Schiff base for simultaneous determination of Cd2+, Cu2+ and Hg2+ ions in water and some foodstuff samples.

Anal Chim Acta 2013 Apr 27;771:21-30. Epub 2013 Feb 27.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A new chemically modified carbon paste electrode was constructed and used for rapid, simple, accurate, selective and highly sensitive simultaneous determination of cadmium, copper and mercury using square wave anodic stripping voltammetry (SWASV). The carbon paste electrode was modified by N,N'-bis(3-(2-thenylidenimino)propyl)piperazine coated silica nanoparticles. Compared with carbon paste electrode, the stripping peak currents had a significant increase at the modified electrode. Under the optimized conditions (deposition potential, -1.100 V vs. Ag/AgCl; deposition time, 60s; resting time, 10s; SW frequency, 25 Hz; pulse amplitude, 0.15 V; dc voltage step height, 4.4 mV), the detection limit was 0.3, 0.1 and 0.05 ng mL(-1) for the determination of Cd(2+), Cu(2+) and Hg(2+), respectively. The complexation reaction of the ligand with several metal cations in methanol was studied and the stability constants of the complexes were obtained. The effects of different cations and anions on the simultaneous determination of metal ions were studied and it was found that the electrode is highly selective for the simultaneous determination of Cd(2+), Cu(2+) and Hg(2+). Furthermore, the present method was applied to the determination of Cd(2+), Cu(2+) and Hg(2+) in water and some foodstuff samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2013.02.031DOI Listing
April 2013

Fabrication of a new electrochemical sensor based on a new nano-molecularly imprinted polymer for highly selective and sensitive determination of tramadol in human urine samples.

Biosens Bioelectron 2013 Jun 16;44:34-40. Epub 2013 Jan 16.

Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.

A new nano-molecularly imprinted polymer bead was synthesized and applied to the fabrication of a chemically modified carbon paste electrode. Nano-molecularly imprinted polymer with molecular recognition capacity was made-up by using [email protected] as the core and the supporting material. The electrode was applied to the simple, rapid, highly selective and sensitive determination of tramadol using square wave voltammetry. The molecularly imprinted polymer and multi-walled carbon nanotubes modified carbon paste electrode was prepared by incorporating the synthesized nano-MIP and multi-walled carbon nanotubes in carbon paste electrode. The limit of detection and the linear range were found to be 0.004 and 0.01 to 20 μmol L(-1) of tramadol, respectively. The effects of potentially interfering substances on the determination of this compound were investigated. And it was found that the electrode is highly selective. The proposed chemically modified carbon paste electrode was used for the determination of tramadol in infected and healthy human urine and pharmaceutical samples.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bios.2012.11.030DOI Listing
June 2013
-->