Publications by authors named "Hosein Khoshsafar"

17 Publications

  • Page 1 of 1

A colorimetric electronic tongue for point-of-care detection of COVID-19 using salivary metabolites.

Talanta 2022 May 14;246:123537. Epub 2022 May 14.

Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran. Electronic address:

The monitoring of profile concentrations of chemical markers in saliva samples can be used to diagnose COVID-19 patients, and differentiate them from healthy individuals. Here, this purpose is achieved by designing a paper-based colorimetric sensor with an origami structure, containing general receptors such as pH-sensitive organic dyes, Lewis donors or acceptors, functionalized nanoparticles, and ion metal complexes. The color changes taking place in the receptors in the presence of chemical markers are visually observed and recorded with a digital instrument. Different types and amounts of the chemical markers provide the sensor with a unique response for patients (60 samples) or healthy (55 samples) individuals. These two categories can be discriminated with 84.3% accuracy. This study evidences that the saliva composition of cured and healthy participants is different from each other with accuracy of 85.7%. Moreover, viral load values obtained from the rRT-PCR method can be estimated by the designed sensor. Besides COVID-19, it may possible to simultaneously identify smokers and people with kidney disease and diabetes using the specified electronic tongue. Due to its high efficiency, the prepared paper device can be employed as a rapid detection kit to detect COVID-19.
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http://dx.doi.org/10.1016/j.talanta.2022.123537DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9107099PMC
May 2022

Wearable Potentiometric Sensor Based on NaMnO for Non-invasive Monitoring of Sodium Ions in Sweat.

Anal Chem 2022 02 20;94(4):2263-2270. Epub 2022 Jan 20.

Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran 1435916471, Iran.

Here, we present a wearable potentiometric ion sensor for real-time monitoring of sodium ions (Na) in human sweat samples using NaMnO as the sensing material. NaMnO is an attractive material for developing wearable electrochemical sensors due to its good Na incorporation ability, electrical conductivity, stability, and low fabrication cost. In the first step, the analytical performance of the electrode prepared using NaMnO is presented. Then, a miniaturized potentiometric cell integrated into a wearable substrate is developed, which reveals a Nernstian response (58 mV dec). We achieved the detection of Na in the linear ranges of 0.21-24.54 mmol L, which is well within the physiological range of Na. Finally, for on-body sweat analysis, the potentiometric sensor is fully integrated into a headband textile. This platform can be employed for non-invasive analysis of Na in human sweat for healthcare and disease diagnosis.
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http://dx.doi.org/10.1021/acs.analchem.1c04960DOI Listing
February 2022

Enzymeless voltammetric sensor for simultaneous determination of parathion and paraoxon based on Nd-based metal-organic framework.

Chemosphere 2022 Apr 29;292:133440. Epub 2021 Dec 29.

Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.

The aim of this work is to fabricate a sensitive and novel enzymeless electrochemical sensor for the simultaneous determination of parathion and paraoxon using the [email protected] nanocomposite. For this purpose, Neodymium (Nd) was introduced into a Universitetet i Oslo (UiO-66) structure to construct Nd-UiO-66 and then, adding multi-walled carbon nanotubes to the Nd-UiO-66 to increase the electrocatalytic activity and surface area of the obtained composite. The [email protected] has numerous advantages like excellent conductivity, tunable texture, and large surface area and can be used as a distinctive structure for the construction of modified glassy carbon electrode (GCE) to enhance the charge-transfer and the efficiency of electrochemical sensors. This modified electrode showed sensitive and selective determination of paraoxon and parathion over the linear ranges of 0.7-100 and 1-120 nM, with detection limits of 0.04 and 0.07 nM, respectively. The proposed [email protected]/GCE sensor in this study can be applied in environmental and toxicological laboratories and field tests to detect parathion and paraoxon levels.
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http://dx.doi.org/10.1016/j.chemosphere.2021.133440DOI Listing
April 2022

Dual-template rectangular nanotube molecularly imprinted polypyrrole for label-free impedimetric sensing of AFP and CEA as lung cancer biomarkers.

Talanta 2022 Mar 13;239:123146. Epub 2021 Dec 13.

Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran. Electronic address:

A high-performance sensing layer based on dual-template molecularly imprinted polymer (DMIP) was fabricated and successfully applied for one-by-one detection of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) as lung cancer biomarkers. The plastic antibodies of AFP and CEA were created into the electropolymerized polypyrrole (PPy) on a fluorine-doped tin oxide (FTO) electrode. Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests were performed to pursue the formation and characterization of the sensing layer. Methyl orange (MO) increased the conductivity of PPy and induced the formation of MO doped PPy (PPy-MO) rectangular-shaped nanotubes. Using impedimetric detection, the rebinding of the template antigens was evaluated, the charge transfer resistance increased as the concentration of AFP and CEA increased. The linear dynamic ranges of 5-10 and 10-10 pg mL and detection limits of 1.6 and 3.3 pg mL were obtained for CEA and AFP, respectively. Given satisfactory results in the determination of AFP and CEA in the human serum samples, high sensitivity, and good stability of DMIP sensor made it a promising method for sensing of AFP and CEA in serum samples.
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http://dx.doi.org/10.1016/j.talanta.2021.123146DOI Listing
March 2022

Electrochemical sandwich-type immunosensor for the detection of PSA based on a trimetallic AgAuPt nanocomposite synthesized using the galvanic replacement reaction.

Anal Methods 2021 09 28;13(33):3676-3684. Epub 2021 Jul 28.

Research and Development Department, Farin Behbood Tashkhis LTD, Tehran, Iran.

A sandwich-type electrochemical immunoassay was introduced for the determination of the prostate-specific antigen (PSA) biomarker. A direct and simple galvanic replacement reaction was performed between the Ag framework and metallic salts of tetrachloroauric(iii) acid trihydrate and chloroplatinic acid to produce a trimetallic composite of AgAuPt. The trimetallic composite of AgAuPt was applied to the preparation of the capture layer of the immunoassay for stabilizing the primary Ab at the surface of the prepared composite. The immunoassay detection layer was also prepared using a labeled antibody containing a bimetallic composite of AgPt as a label. The various procedures in the immunoassay fabrication were monitored step by step using cyclic voltammetry and electrochemical impedance spectroscopy. Also, the electrochemical determination of PSA was performed using differential pulse voltammetry in the presence of the ferrocene redox probe and HO. Furthermore, the effective parameters in the fabrication of the immunoassay included the drop volume of the AgAuPt trimetallic composite and the incubation time for the immobilization of biomolecules (i.e., Ab, BSA, PSA, and labeled Ab), and the concentration of HO were optimized during the determination of PSA. Then, the determination of PSA was performed under optimized conditions. It could be seen that there was a linear relation between the PSA concentration and DPV responses in the concentration range of 50 pg mL to 500 ng mL and the limit of detection (LOD) for the proposed immunoassay was calculated as 17.0 pg mL. In the following investigation, the cross-reactivity of the proposed immunoassay was studied in the presence of BSA, CEA, IgG, and human hepatitis surface antigen, in which the results showed a negligible change in the performance of the immunoassay.
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http://dx.doi.org/10.1039/d1ay01004bDOI Listing
September 2021

Colorimetric immunosensor for determination of prostate specific antigen using surface plasmon resonance band of colloidal triangular shape gold nanoparticles.

Spectrochim Acta A Mol Biomol Spectrosc 2019 Nov 29;222:117218. Epub 2019 May 29.

Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran. Electronic address:

In this work, we demonstrated the development of a colorimetric immunosensor using surface plasmon resonance band of gold nanoparticles for the detection of prostate specific antigen (PSA). To develop this biosensing tool, triangular gold nanoparticles (AuNPs) were synthesized using Tween-20 as a nonionic surfactant and then, conjugated with PSA capture antibody (Ab-AuNPs). When exposed to Ab-AuNPs, PSA antigens were found to be successfully captured by nanosystem (PSA)-Ab-AuNPs. Next, (PSA)-Ab-AuNPs were incubated with second PSA antibody (2)-decorated magnetite (FeO-Ab) and separated by an external magnetic force to leave Ab-AuNPs in the supernatant solution to be directly analyzed using UV-Vis spectroscopy. It was found that the absorption intensity was directly proportional to the PSA concentration. As a result, the linear range for PSA detection was found to be 0.01-20 ng mL with a detection limit of 0.009 ng mL. Because of significant stability of the prepared Ab-AuNPs and excellent selectivity to the PSA antigen, this simple and sensitive sensing system is proposed to be potentially effective in the fast and real-time analysis of clinical samples from prostate cancer patients. We believe that the simple platform of this immunosensor to be useful in the development of future point-of-care sensing tools, working on the quantification of biomarkers in a drop of blood.
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http://dx.doi.org/10.1016/j.saa.2019.117218DOI Listing
November 2019

Dual-modality impedimetric immunosensor for early detection of prostate-specific antigen and myoglobin markers based on antibody-molecularly imprinted polymer.

Talanta 2019 Sep 27;202:111-122. Epub 2019 Apr 27.

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

A new dual-modality immunosensor based on molecularly imprinted polymer (MIP) and a nanostructured biosensing layer has fabricated for the simultaneous detection of two important markers including prostate-specific antigen (PSA) and myoglobin (Myo) in human serum and urine samples. In the first step, 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) (DSP) was self-assembled on a gold screen printed electrode (SPE). Then, the target proteins were attached covalently to the DSP-SPE. The imprinted cocktail polymer ((MIP(PSA, Myo)-SPE)) was synthesized at the SPE surface using acrylamide as monomer, N,N'-methylenebisacrylamide as a crosslinker, and PSA and Myo as the templates, respectively. The MIP-SPE was specific for the impedimetric sensing of PSA and Myo. After that, a nanocomposite (NCP) was synthesized based on the decorated magnetite nanoparticles with multi-walled carbon nanotube, graphene oxide and specific antibody for PSA (Ab). Then, NCP incubated with (MIP(PSA, Myo)-SPE. The modified electrodes and synthesized nanoparticles were characterized using electrochemical impedance spectroscopy, dynamic light scattering, surface plasmon resonance and scanning electron microscopy. The limits of detections were found to be 5.4 pg mL and 0.83 ng mL with the linear dynamic ranges of 0.01-100 and 1-20000 ng mL for PSA and Myo, respectively. The ability of proposed biosensor to detect PSA and Myo simultaneously with high sensitivity and specificity offers a powerful opportunity for the new generation of biosensors. This dual-analyte specific receptors-based device is highly desired for the integration with lab-on-chip kits to measure a wide panel of biomarkers present at ultralow levels during early stages of diseases progress.
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http://dx.doi.org/10.1016/j.talanta.2019.04.061DOI Listing
September 2019

Reduced graphene oxide decorated on Cu/CuO-Ag nanocomposite as a high-performance material for the construction of a non-enzymatic sensor: Application to the determination of carbaryl and fenamiphos pesticides.

Mater Sci Eng C Mater Biol Appl 2019 Sep 7;102:764-772. Epub 2019 May 7.

Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran. Electronic address:

A novel electrochemical sensor based on the reduced graphene oxide-Cu/CuO-Ag nanocomposite modified glassy carbon electrode (rGO/Cu/CuO-Ag/GCE) has been applied for the simultaneous analysis of carbaryl and fenamiphos as two important pesticides. The electrochemical behavior of carbaryl and fenamiphos at rGO/Cu/CuO-Ag/GCE was studied by cyclic voltammetry and differential pulse voltammetry. The modified electrode exhibited two separated oxidation signals for the simultaneous determination of both carbaryl and fenamiphos with excellent sensitivity. The characteristics of the modified electrode were studied with transmission electron microscopy, X-ray diffraction and Fourier transform-infrared spectroscopy techniques. Under optimized conditions, the rGO/Cu/CuO-Ag/GCE detected carbaryl and fenamiphos with the wide linear ranges of 0.05-20 and 0.01-30 μM, and the detection limits were 0.005 and 0.003 μM, respectively. This developed electrochemical platform applied as a simple and cost-effective sensor for the detection of low levels of carbaryl and fenamiphos in fruit and vegetable samples successfully.
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http://dx.doi.org/10.1016/j.msec.2019.05.010DOI Listing
September 2019

Enhanced Visual Wireless Electrochemiluminescence Immunosensing of Prostate-Specific Antigen Based on the Luminol Loaded into MIL-53(Fe)-NH Accelerator and Hydrogen Evolution Reaction Mediation.

Anal Chem 2019 05 23;91(9):6383-6390. Epub 2019 Apr 23.

Chemical Injuries Research Center, Systems Biology and Poisonings Institute , Baqiyatallah University of Medical Sciences , 14359-16471 Tehran , Iran.

A sensitive prostate-specific antigen (PSA) detection method using a visual-readout closed bipolar electrode (BPE) system has been introduced by integration of hydrogen evolution reaction (HER) in cathodic pole and electrochemiluminescence (ECL) of luminol loaded within the MIL-53(Fe)-NH ([email protected](Fe)-NH) in the anodic pole. The cathode of the BPE was electrochemically synthesized by 3D porous copper foam, followed by decorating with nitrogen-doped graphene nanosheet and ruthenium nanoparticles. As an alternative, we employed carboxylate-modified magnetic nanoparticles (MNPs) for immobilization of the primary antibody (Ab1) and utilized the [email protected](Fe)-NH conjugated to secondary antibody (Ab2) as a signaling probe and coreaction accelerator. After sandwiching the target PSA between Ab1 and Ab2, the MNP/Ab1-PSA-Ab2/[email protected](Fe) were introduced to a gold anodic BPE. Finally, the resulting ECL of luminol and HO at the anodic poles was monitored using a photomultiplier tube (PMT) or digital camera. The PMT and visual (camera)-based detections showed linear responses from 1 pg mL to 300 ng mL (limit of detection 0.2 pg mL) and 5 pg mL to 200 ng mL (limit of detection 0.1 pg mL), respectively. This strategy provides an effective method for high-performance bioanalysis and opens a new door toward the development of the highly sensitive and user-friendly device.
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http://dx.doi.org/10.1021/acs.analchem.9b01506DOI Listing
May 2019

Nanomolar simultaneous determination of tryptophan and melatonin by a new ionic liquid carbon paste electrode modified with [email protected] nanocomposite.

Mater Sci Eng C Mater Biol Appl 2017 Feb 17;71:386-394. Epub 2016 Oct 17.

Laboratory for Sensors, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges Köhler Allee 103, 79110 Freiburg, Germany.

This work describes the development of a new sensor for simultaneous determination of tryptophan and melatonin. The proposed sensor was an ionic liquid carbon paste electrode modified with reduced graphene oxides decorated with SnO-CoO nanoparticles. The voltammetric oxidation of the analytes by the proposed sensor confirmed that the electrooxidation process undergoes a two-electron/one-proton reaction for melatonin and a two-electron/two-proton reaction for tryptophan in diffusion-controlled processes. Moreover, based on the excellent electrochemical properties of the modified electrode, a sensitive voltammetric method was used for individual and simultaneous determination of melatonin and tryptophan in the aqueous solutions. Under the optimized experimental conditions, a linear response obtained in the range of 0.02 to 6.00μmolL with detection limits of 4.1 and 3.2nmolL for melatonin and tryptophan, respectively. The prepared sensor possessed accurate and rapid response toward melatonin and tryptophan with a good sensitivity, selectivity, stability, and repeatability. Finally, the applicability of the proposed sensor was verified by evaluation of melatonin and tryptophan in various real samples including human serum and tablet samples.
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http://dx.doi.org/10.1016/j.msec.2016.10.020DOI Listing
February 2017

Protein capped Cu nanoclusters-SWCNT nanocomposite as a novel candidate of high performance platform for organophosphates enzymeless biosensor.

Biosens Bioelectron 2017 Mar 4;89(Pt 2):829-836. Epub 2016 Oct 4.

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

A biocompatible nanocomposite including bovine serum albumin (BSA) template Cu nanoclusters ([email protected]) and single-walled carbon nanotubes (SWCNT) was synthesized to fabricate a highly sensitive electrochemical biosensor for paraoxon as a model of organophosphates. The UV-vis, fluorescence and Fourier transform infrared (FTIR) demonstrated that BSA entrapped in the nanocomposite film have been changed in its secondary structure so that it provided an enzyme like activity attributing to the high electrical conductivity of the entrapped copper nanoclusters. Also, the morphology and structure of prepared nanocomposites were investigated by transmission electronic microscopy (TEM) and scanning electron microscopy (SEM). In the prepared nanocomposite, the [email protected] found to play as a conductive holder as well as an accumulator of redox active centers on the surface of the electrode, and SWCNT improves the electrocatalytic activity along with conductivity of glassy carbon electrode (GCE) surface. The fabricated biosensor exhibited excellent sensitivity, acceptable stability, fast response, and high electrocatalytic activity toward the reduction of paraoxon. The reduction peak current vs paraoxon concentration was linear over the range 50nM to 0.5μM and 0.5-35μM, with a limit of detection of 12.8nM. Notable electrocatalytic properties of the developed electrode toward paraoxon indicated that the nanocomposite possesses a promising potential to fabricate the third generation enzyme-free electrochemical biosensors, bioelectronics and state-of-the-art biomedical devices in the future.
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http://dx.doi.org/10.1016/j.bios.2016.10.003DOI Listing
March 2017

Simultaneous electrochemical sensing of thallium, lead and mercury using a novel ionic liquid/graphene modified electrode.

Anal Chim Acta 2015 Apr 3;870:56-66. Epub 2015 Mar 3.

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

In the present manuscript, an electrochemical sensor for the sensitive detection of Tl(+), Pb(2+) and Hg(2+) is described. A new composite electrode has been fabricated using graphene, 1-n-octylpyridinum hexafluorophosphate (OPFP), and [2,4-Cl2C6H3C(O)CHPPh3] (L), as a new synthetic phosphorus ylide. The physicochemical and electrochemical characterizations of fabricated sensor were investigated in details. The advantages of the proposed composite electrode are its ability in simultaneous electrochemical detection of Tl(+), Pb(2+) and Hg(2+) with good selectivity, stability and no need for separating of the three species from complex mixtures prior to electrochemical measurements. The analytical performance of the proposed electrode was examined using square wave voltammetry. Tl(+), Pb(2+) and Hg(2+) can be determined in linear ranges from 1.25×10(-9) to 2.00×10(-7) mol L(-1). Low detection limits of 3.57×10(-10) mol L(-1) for Tl(+), 4.50×10(-10) mol L(-1) for Pb(2+) and 3.86×10(-10) mol L(-1) for Hg(2+) were achieved. Finally, the proposed electrochemical sensor was applied to detect trace analyte ions in various water and soil samples with satisfactory results.
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http://dx.doi.org/10.1016/j.aca.2015.03.004DOI Listing
April 2015

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

Facile stripping voltammetric determination of haloperidol using a high performance magnetite/carbon nanotube paste electrode in pharmaceutical and biological samples.

Mater Sci Eng C Mater Biol Appl 2014 Apr 18;37:264-70. Epub 2014 Jan 18.

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

Multi-walled carbon nanotubes decorated with Fe3O4 nanoparticles were prepared to construct a novel sensor for the determination of haloperidol (Hp) by voltammetric methods. The morphology and properties of electrode surface were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy. This modified sensor was used as a selective electrochemical sensor for the determination of trace amounts of Hp. The peak currents of differential pulse and square wave voltammograms of Hp increased linearly with its concentration in the ranges of 1.2×10(-3)-0.52 and 6.5×10(-4)-0.52μmol L(-1), respectively. The detection limits for Hp were 7.02×10(-4) and 1.33×10(-4)μmol L(-1) for differential pulse and square wave voltammetric methods, respectively. The results show that the combination of multi-walled carbon nanotubes and Fe3O4 nanoparticles causes a dramatic enhancement in the sensitivity of Hp quantification. This sensor was successfully applied to determine Hp in pharmaceutical samples and biological fluids. The fabricated electrode showed excellent reproducibility, repeatability and stability.
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http://dx.doi.org/10.1016/j.msec.2014.01.023DOI 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.
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http://dx.doi.org/10.1016/j.msec.2013.10.025DOI Listing
February 2014

Simultaneous trace-levels determination of Hg(II) and Pb(II) ions in various samples using a modified carbon paste electrode based on multi-walled carbon nanotubes and a new synthesized Schiff base.

Anal Chim Acta 2012 Oct 23;746:98-106. Epub 2012 Aug 23.

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

A modified carbon paste electrode based on multi-walled carbon nanotubes (MWCNTs) and 3-(4-methoxybenzylideneamino)-2-thioxothiazolodin-4-one as a new synthesized Schiff base was constructed for the simultaneous determination of trace amounts of Hg(II) and Pb(II) by square wave anodic stripping voltammetry. The modified electrode showed an excellent selectivity and stability for Hg(II) and Pb(II) determinations and for accelerated electron transfer between the electrode and the analytes. The electrochemical properties and applications of the modified electrode were studied. Operational parameters such as pH, deposition potential and deposition time were optimized for the purpose of determination of traces of metal ions at pH 3.0. Under optimal conditions the limits of detection, based on three times the background noise, were 9.0×10(-4) and 6.0×10(-4) μmol L(-1) for Hg(II) and Pb(II) with a 90 s preconcentration, respectively. In addition, the modified electrode displayed a good reproducibility and selectivity, making it suitable for the simultaneous determination of Hg(II) and Pb(II) in real samples such as sea water, waste water, tobacco, marine and human teeth samples.
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http://dx.doi.org/10.1016/j.aca.2012.08.024DOI Listing
October 2012

Preparation and characterization of magnetic nanocomposite of Schiff base/silica/magnetite as a preconcentration phase for the trace determination of heavy metal ions in water, food and biological samples using atomic absorption spectrometry.

Talanta 2012 Aug 24;97:87-95. Epub 2012 Apr 24.

Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran.

A versatile and robust solid phase with both magnetic property and a very high adsorption capacity is presented on the basis of modification of iron oxide-silica magnetic particles with a newly synthesized Schiff base (Fe(3)O(4)/SiO(2)/L). The structure of the resulting product was confirmed by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) spectrometry and transmission electron microscopy (TEM). We developed an efficient and cost-effective method for the preconcentration of trace amounts of Pb(II), Cd(II) and Cu(II) in environmental and biological samples using this novel magnetic solid phase. Prepared magnetic solid phase is an ideal support because it has a large surface area, good selectivity and can be easily retrieved from large volumes of aqueous solutions. The possible parameters affecting the enrichment were optimized. Under the optimal conditions, the method detection limit was 0.14, 0.19 and 0.12 μg L(-1) for Pb(II), Cd(II) and Cu(II) ions, respectively. The established method has been successfully applied to analyze real samples, and satisfactory results were obtained. All these indicated that this magnetic phase had a great potential in environmental and biological fields.
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http://dx.doi.org/10.1016/j.talanta.2012.03.066DOI Listing
August 2012
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