Biomedical subjects

Mohammad Reza Ganjali

Publications and source records attributed to Mohammad Reza Ganjali.

At least 19 recordsLinked to original sources

PubMed2006

Development of fast Fourier transformation continuous cyclic voltammetry as a highly sensitive detection system for ultra trace monitoring of penicillin V.

Fast continuous cyclic voltammetry was used as a detection method for penicillin V in a flow injection system. Additionally, a special computer-based numerical calculation method (using fast Fourier transformation) providing enhancement of the analyte signal and noise reduction is introduced here. During the measurements, the potential waveform (consisting of the potential steps of cleaning, stripping, and the potential ramp) was continuously applied to an Au disk microelectrode (12.5 microm in radius). In particular, the effects of accumulation potential, sweep rate, and delay time on the sensitivity and selectivity of the method were investigated. Eventually, the stripping time was found to be less than 300 ms, the detection limit of the method was 7.0x10(-12) M, and the associated relative standard deviation at 5.0x10(-6) M penicillin V was 2.3 for eight runs.

Electrochemistry↗

PubMed2006

A sub-second fast Fourier transform-adsorptive voltammetric technique for the nano-level determination of guthion at a gold microelectrode in flowing solutions.

This research demonstrates the quick guthion monitoring with the help of a sensitive method called fast Fourier transformation continuous cyclic voltammetry (FFTCV). Fortunately, FFTCV illustrates the benefits of precision, determination speed, cost-effectiveness, accuracy and simplicity, in comparison with formerly reported techniques. In particular, this method was applied to a gold microelectrode in flowing solutions to detect the guthion concentration in its formulations. The effects of several parameters were examined regarding the sensitivity of the method. After a series of experiments, the detection limit of the method was found to be equal to 1.27 pg/mL, when the optimum conditions were imposed, which is a scan rate value of 40V/s, an accumulation time of 0.4s, an accumulation potential of 0mV and a pH value of 2. During the measurements performance, the integration range of currents included all the potential scan ranges, even the oxidation and reduction of the Au surface electrode, for the achievement of a sensitive determination. Then, the potential waveform, consisting of the potential steps for cleaning, accumulation and the step for the potential ramp, was applied to an Au disk microelectrode in a continuous way. It is also important to refer to the positive points, presented only by the use of this technique. Firstly, it is no longer necessary to remove the oxygen from the test solution. Furthermore, the quick determination of any such compound in many chromatographic methods is possible. Thirdly, the corresponding detection limit is of nanomolar level.

Azinphosmethyl↗

PubMed2006

Sub-second adsorptive fast Fourier transform coulometric technique as a novel method for the determination of nanomolar concentrations of sodium valproate in its pharmaceutical preparation in flowing solution systems.

In this work, a novel electrochemical technique has been developed for determination of nanomolar concentration of sodium valproate in flow-injection systems. The detection was done by adsorptive fast Fourier transform coulometric (AFFTC), in which the potential waveform consists of potential steps for cleaning, accumulation, and a potential ramp that was continuously applied on an Au disk microelectrode. Moreover, a special computer program is introduced based on numerical method, for calculation of the analyte signal (which is the partial and total charge exchanges at the electrode surface) and noise reduction. The optimum parameters were: pH value of 2.0, scan rate value of 40 Vs(-1), accumulation potential of 200 mV and accumulation time of 0.3 s. Detection limit of the method for sodium valproate was 9.0x10(-9) M. The relative standard deviation of the method at 1.3x10(-7) M was 2.0% for 10 runs.

Electrochemistry↗

PubMed2006

A green method for the electroorganic synthesis of new 1,3-Indandione derivatives.

This is an environmentally friendly method in the field of electroorganic reactions under controlled potential electrolysis, without toxic reagents at a carbon electrode in an undivided cell which involves the (EC) mechanism reaction and comprises two steps alternatively; (i) electrochemical oxidation and (ii) chemical reaction. In particular, the electrochemical oxidation of 4-tert-butylcatechol, 4-methylcatechol and 2,3-dihydroxybenzoic acid in the presence of 2-phenyl-1,3-indandione has been studied in a water-acetonitrile (90 : 10) mixture. The research includes the use of a variety of experimental techniques, such as cyclic voltammetry, controlled-potential electrolysis, and spectroscopic identification of products (FT-IR, (1)H-NMR, and MS spectrometry).

Carbon↗

PubMed2006

Synthesis of N'-(1-pyridin-2-ylmethylene)-2-furohydrazide and its application in construction of a highly selective PVC-based membrane sensor for La(III) ions.

A highly La(III) ion-selective PVC membrane sensor based on N'-(1-pyridin-2-ylmethylene)-2-furohydrazide (NPYFH) as an excellent sensing material was successfully developed. The electrode shows a good selectivity for La(III) ion with respect to most common cations including alkali, alkaline earth, transition and heavy metal ions. The proposed sensor exhibits a wide linear response with slope of 19.2 +/- 0.6 mV per decade over the concentration range of 1.0 x 10(-6) - 1.0 x 10(-1) M, and a detection limit of 7.0 x 10(-7) M of La(III) ions. The sensor response is independent of pH in the range of 3.5-10.0. The proposed electrode was applied as an indicator electrode in potentiometric titration of La(III) ion with EDTA.

Furans↗

PubMed2004

ppt level detection of samarium(III) with a coated graphite sensor based on an antibiotic.

N-[2-[4-[[[(Cyclohexylamino)carbonyl]amino]sulfonyl]phenyl]ethyl]-5-methyl pyrazine carboxamide (glipizid) was explored as an electro-active material for preparing a polymeric membrane-based sensor selective to samarium ions. The membrane incorporated 30% poly(vinyl chloride) (PVC), 53% benzyl acetate (BA), 11% glipizid and 6% sodium tetraphenyl borate. When coated on the surface of a graphite electrode, it exhibits Nernstian responses in the concentration range of 1.0 x 10(-5) to 1.0 x 10(-10) M, with a detection limit of 8.0 x 10(-11)M samarium. The electrode shows high selectivity towards samarium over several cations (alkali, alkaline earth, transition and heavy metal ions), and specially lanthanide ions. The proposed sensor has a very short response time (< 15 s), and can be used in a wide pH range for at least ten weeks. It was used as an indicator electrode in potentiometric titration of Sm(III) ions with an EDTA solution, and for determination of samarium in binary and ternary mixtures.

Anti-Bacterial Agents↗

PubMed2004

An Eu(III) sensor based on N,N-diethyl-N-(4-hydroxy-6-methylpyridin-2-yl)guanidine.

A highly selective poly(vinyl chloride)-based membrane sensor produced by using N,N-diethyl-N-(4-hydroxy-6-methylpyridin-2-yl)guanidine (GD) as active material is described. The electrode displays Nernstian behavior over the concentration range 7.0 x 10(-5) - 1.0 x 10(-1) M. The detection limit of the electrode is 5.0 x 10(-5) M. The best performance was obtained with the membrane containing 30% PVC, 55% benzyl acetate, 5% GD and 10% oleic acid. The response of the sensor is pH-independent in the range of 3.0 - 7.0. The sensor possesses satisfactory reproducibility, fast response time (< 20 s), and specially excellent discriminating ability for Eu(III) ion with respect to the alkali, alkaline earth, transition and heavy metal ions. The membrane sensor was used as an indicator electrode in potentiometric titration of Eu(III) ion with EDTA. It was also applied in determination of fluoride ions in mouth wash preparations.

Europium↗

PubMed2004

Synthesis of a new oxime and its application to the construction of a highly selective and sensitive Co(II) PVC-based membrane sensor.

A cobalt(II) ion-selective membrane sensor has been fabricated from a poly vinyl chloride (PVC) matrix membrane containing a new oxime compound (oxime of 1-(2-oxocyclohexyl)-1,2-cyclohexanediol, OXCCD) as a neutral carrier, sodium tetraphenyl borate (NaTPB) as an anionic excluder and o-nitrophenyloctylether (o-NPOE) as a plasticizing solvent mediator. The membrane sensor exhibits a linear potential response in the concentration range of 1.0 x 10(-1) - 1.0 x 10(-6) M of Co2+. The electrode displays a Nernstian slope of 29.8 mV decade(-1) in the pH range of 3.5 - 8.0. The sensor also exhibits a fast response time of < 25 s. The detection limit of the proposed sensor is 9.0 x 10(-7) M (approximately 40 ng/ml), and it can be used over a period of two months. The selectivity of the sensor with respect to other cations (alkali, alkaline earth, transition and heavy metal ions) is excellent. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of Co2+ with EDTA and for the direct determination of Co(II) in wastewater of the electroplating industry.

Journal Article↗

PubMed2004

Novel method for the fast preconcentration and monitoring of a ppt level of lead and copper with a modified hexagonal mesoporous silica compound and inductively coupled plasma atomic emission spectrometry.

A novel method for the rapid extraction and determination of a ppt level of Pb2+ and Cu2+ ions using partial silylated MCM-41 modified by a new salophen and inductively coupled plasma atomic emission spectrometry (ICP-AES) is introduced. The preconcentration factor of the method is 500, and the detection limits of Pb2+ and Cu2+ are 335 and 34 ng L(-1), respectively. The time and efficiency of extraction, the pH and flow rate, the type and minimum amount of acid for stripping of Pb2+ and Cu2+ from modified MCM-41 and the break-through volume were investigated. The maximum capacity of 4 mg of silylated MCM-41 modified by salophen used was found to be 150 +/- 4 and 117 +/- 3 microg of Pb2+ and Cu2+, respectively.

Journal Article↗

PubMed2003

PVC membrane and coated graphite potentiometric sensors based on Et4todit for selective determination of samarium(III).

Solution studies on the binding properties of 4,5,6,7-tetrathiocino[1,2-b:3,4-b']diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione (Et(4)todit) toward a number of cationic species including some lanthanide ions revealed the occurrence of a selective 1:1 complexation of the ligand with Sm(3+) ion. Consequently, Et(4)todit was used as a suitable neutral ionophore for the preparation of novel polymeric membrane (PME) and coated graphite (CGE) Sm(3+)-selective electrodes. The electrodes exhibit a Nernstian behavior for Sm(3+) ions over wide concentration ranges (1.0 x 10(-5)-1.0 x 10(-1) M for PME and 1.0 x 10(-7)-1.0 x 10(-1) M for CGE) and very low limits of detection (8.0 x 10(-6) M for PME and 1.6 x 10(-8) M for CGE). The proposed potentiometric sensors manifest advantages of relatively fast response, and, most importantly, good selectivities relative to wide variety of other cations, including other lanthanide ions. The selectivity behavior of the proposed Sm(3+)-selective electrodes revealed a great improvement compared to the best previously reported electrode for samarium(III) ion. The potentiometric responses of the electrodes are independent of the pH of the test solution in the pH range 4.0-6.5. The electrodes were successfully applied to the recovery of Sm(3+) ion from tap water samples and also, as an indicator electrode, in potentiometric titration of samarium(III) ions.

Journal Article↗

PubMed2003

PVC-membrane ion-selective bulk optode for Ag+ ion based on hexathia-18-crown-6 and 1,2-benzo-3-octadecanoylimino-7-diethylaminophenoxazine.

A silver-selective optode membrane incorporating hexathia-18-crown-6 for cation recognition and a lipophilic chromoionophore 1,2-benzo-3-octadecanoylimino-7-diethylaminophenoxazine for transduction has been prepared. The PVC membrane composition was optimized to result in the largest working concentration range. The response range of the proposed optode is 5.0 x 10(-9)-5.0 x 10(-5) mol L(-1) Ag(+) with a limit of detection of 1.0 x 10(-9) mol L(-1). The probe works well at pH 5.0 and revealed small ion interference and good selectivity, reproducibility and stability.

Journal Article↗

PubMed2003

Highly selective PVC-membrane electrodes based on Co(II)-Salen for determination of nitrite ion.

A cobalt(II) derivative was used as a suitable ionophore for the preparation of a polymeric membrane nitrite-selective electrode. The electrode reveals a Nemstian behavior over a very wide NO2- ion concentration range (1.0 x 10(-6)-1.0 x 10(-1) M) and a very low detection limit (5.0 x 10(-7) M). The potentiometric response is independent of the pH of solution in the pH range 4.0-9.5. The electrode shows advantages such as low resistance, fast response and, most importantly, good selectivity relative to a wide variety of inorganic and organic anions. In fact, the selectivity behavior of the proposed NO2- ion-selective electrode shows great improvements compared to the previously reported electrodes for nitrite ion. The proposed electrodes could be used for at least 2 months without any significant changes in potentials. The electrode was successfully applied to the determination of nitrate ion concentrations in sausage and milk samples.

Journal Article↗

PubMed2003

Novel imidazole PVC-based sensor based on a thiopyrilium compound.

A novel imidazole membrane sensor based on 2,4,6-triphenyl thiopyrilium perchlorate (TTP) as an excellent charged carrier, poly(vinyl chloride) (PVC), the plasticizer dibutyl phthalate (DBP) and oleic acid as an additive is described. The sensor responds to imidazole over a wide concentration range from 1.0 x 10(-5) to 1.0 x 10(-1) M with a slope of +33.5 +/- 0.5 mV per decade. The detection limit of the electrode is 3.0 x 10(-6) M and it can be used for at least four weeks without any measurable change in sensitivity. The sensitivity of the electrode is high enough to permit the detection of as little as 0.2 microg/ml of imidazole without any significant interference from high levels of other components and especially, amino acids. The potentiometric selectivity coefficient data revealed negligible interference from common cations, anions and amino acids. The electrode has a relatively fast response time (<30 s), and good slope stability. The proposed sensor was successfully applied to the determination of imidazole in synthetic serum samples.

Journal Article↗

PubMed2003

Novel PVC-based copper(II) membrane sensor based on 2-(1'-(4'-(1''-hydroxy-2''-naphthyl)methyleneamino)butyl iminomethyl)-1-naphthol.

A copper(II) ion-selective PVC membrane sensor based on 2-(1'-(4'-(1''-hydroxy-2''-naphthyl)methyleneamino)butyl iminomethyl)-1-naphthol (BHNB) as a novel Schiff base containing a sensing material has been successfully developed. The sensor exhibits a good linear response of 29 mV per decade within the concentration range of 10(-1)-10(-6) M of Cu2+. The sensor shows good selectivity for copper(II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. The BHNB-based sensor is suitable for use with aqueous solutions of pH 3.5-7.0 and displays minimal interference by Sr(II), Cd(II), Hg(II), Zn(II) and Pb(II), which are known to interfere with other previously suggested electrodes. The proposed membrane electrode was used as a sensor for determining the Cu(II) content in black tea samples. It was also applied as an indicator electrode in the potentiometric titration of Cu2+ ions with EDTA.

Copper↗

PubMed2003

Novel potentiometric membrane sensor for the determination of trace amounts of chromium(III) ions.

A plasticized Cr3+ ion sensor by incorporating 2,3,8,9-tetraphenyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene (TTCT) ionophore exhibits a good potentiometric response for Cr3+ over a wide concentration range (1.0 x 10(-6)-1.0 x 10(-1) M) with a slope of 19.5 mV per decade. The sensor response is stable for at least three months. Good selectivity for Cr3+ in comparison with alkali, alkaline earth, transition and heavy metal ions, and minimal interference are caused by Li+, Na+, K+, Co2+, Hg2+, Ca2+, Pb2+ and Zn2+ ions, which are known to interfere with other chromium membrane sensors. The TTCT-based electrode shows a fast response time (15 s), and can be used in aqueous solutions of pH 3-5.5. The proposed sensor was used for the potentiometric titration of Cr3+ with EDTA and for a direct potentiometric determination of Cr3+ content in environmental samples.

Chromium↗

PubMed2003

Novel potentiometric sensor for monitoring beryllium based on naphto-9-crown-3.

A novel poly(vinyl chloride) (PVC) membrane electrode based on naphto-9-crown-3 was prepared and tested for the selective detection of beryllium ions. A suitable lipophilicity of the carrier and appropriate coordination ability were found to be essential for designing an electrode with good response characteristics. A PVC membrane with 9% naphtho-9-crown-3 carrier, 58% o-NPOE plasticizer, 3% tetraphenylborate anionic excluder and 30% poly(vinyl chloride) satisfied these requirements. The proposed sensor displayed a linear response to beryllium over a wide concentration range of 1.0 x 10(-1)-8.0 x 10(-6) M with a Nernstian slope of 29.5 mV per decade. The electrode showed very short response time (<15 s) and could be used in the pH range 3.5-9.0. The selectivity coefficient for alkali, alkaline earth, transition and heavy metal ions was smaller than 4.0 x 10(-4). The sensor was successfully used as an indicator electrode in the potentiometric titration of Be2+ with EDTA. The proposed Be(II) sensor was also used for the determination of Be2+ ions in binary mixtures.

Journal Article↗

PubMed2003

Novel membrane potentiometric sulfate ion sensor based on zinc-phthalocyanine for the quick determination of trace amounts of sulfate.

Poly(vinyl chloride) (PVC) based membranes of zinc-phthalocyanine (ZPC) with hexadecyltrimethylammonium bromide (HTAB) as a cation excluder, and dibutyl phthalate (DBP) and benzyl acetate (BA) as plasticizing solvent mediators were prepared and investigated as a SO4(2-) selective electrode. The best performance was observed with a membrane having a composition of ZPC-PVC-HTAB-BA in a ratio of 5%:32%:3%:60%, which works well over a wide concentration range (1.0 x 10(-2) - 1.0 x 10(-6) M) with a Nemstian slope of -29.2 mV per decade of activity, between the pH values of 2.0 to 7.0. This sensor shows a very fast response time of 10 s, and can be used over a period of 2 months with good reproducibility. The proposed sensor displays excellent selectivity for SO4(2-) over a large number of common inorganic anions. The sensor has been successfully applied for the direct and indirect determination of sulfate and zinc in zinc sulfate tablets, respectively. It was also used as an indicator electrode in the potentiometric titration of sulfate ions with barium ions.

Journal Article↗

PubMed2002

Lanthanum(IlI) PVC membrane electrodes based on 1,3,5-trithiacyclohexane.

Novel plasticized polymeric membrane (PPME) and membrane-coated graphite (MCGE) electrodes based on 1,3,5-trithiacyclohexane for highly selective determination of La3+ ion have been developed. The electrodes exhibit Nernstian responses over very wide concentration ranges (8.0 x 10(-6)-5.0 x 10(-2) M for PPME and 4.0 x 10(-8)-1.0 x 10(-2) M for MCGE). The limit of detections were 5.0 x 10(-6) and 2.0 x 10(-8) M for PPME and MCGE, respectively. The electrodes possess a fast response time of approximately 10 s and can be used for at least 6 months without observing any deviation. The proposed electrodes revealed excellent selectivities for La3+ over a wide variety of alkali, alkaline earth, transition, and heavy metal ions and could be used in a pH range of 5.0-8.0. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of La3+ ions with EDTA and in determination of F- in some mouthwash preparations.

Cyclohexanes↗