Maryam Abbasghorbani - Academia.edu (original) (raw)
Papers by Maryam Abbasghorbani
Bulletin of the Korean Chemical Society, 2005
Bis(2-methylbenzaldehyde)butane-2,3-dihydrazone(TDSB) was used as new N-N Schiff's base which pla... more Bis(2-methylbenzaldehyde)butane-2,3-dihydrazone(TDSB) was used as new N-N Schiff's base which plays the role of an excellent ion carrier in the construction of a La(III) membrane sensor. The best performance was obtained with a membrane containing, 30% poly(vinyl chloride), 60% benzyl acetate, 6% TDSB and 4% sodium tetraphenyl borate. This sensor reveals a very good selectivity towards La(III) ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The proposed electrode exhibits a Nernstian behavior (with slope of 19.8 mV per decade) over a wide concentration range (1.0 × 10 −5-1.0 × 10 −1 M). The detection limit of the sensor is 7.0 × 10 −6 M. It has a very short response time, in the whole concentration range (~5 s), and can be used for at least twelve weeks in the pH range of 3.0-9.4. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a La(III) solution, with EDTA. It was also successfully applied in the determination of fluoride ions in three mouth wash preparations.
Bulletin of the Korean Chemical Society, 2004
A highly selective membrane electrode based on1,3,5-triphenylpyrylium perchlorate (TPPP) is prese... more A highly selective membrane electrode based on1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of-29.7 mV per decade. The working concentration ranges of the electrode is 1.0 x 10-1-6.3 x 10-6 M with a detection limit of 4.0 x 10-6 M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate.
Journal of Solution Chemistry
Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial... more Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial gas streams such as natural gas, liquefied natural gas and liquefied petroleum gas streams and it has to be removed down to very low concentrations to meet the required specifications. In this article, the propane was contaminated (400–5200 ppmw, part per million by weight) with hydrogen sulfide and carbonyl sulfide and was treated using diethanolamine, 30 mass%, at temperatures 313.15 and 333.15 and the effect of aqueous DEA solution on the separation was investigated.
A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) c... more A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) carbon paste electrode (NiO/NPs/CPE) as high sensitive sensors for voltammetric determination of Nalbuphine (NB). The NiO/NPs was characterized with different methods such as SEM and XRD. The cyclic voltammogram showed an irreversible oxidation peak at 0.57 V (vs. Ag/AgClsat), which corresponded to the oxidation of NB. Compared to common carbon paste electrode, the electrochemical response was greatly improved. The electro-oxidation of NB occurred in a pH-dependent 1e− and 1H + process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions, the voltammetric oxidation peak current of NB showed linear dynamic ranges with a detection limit of 0.5 μM for NB. The novel sensor has been found selective and successfully implemented for the determination of NB in water, serum and urine samples.
Journal of Solution Chemistry
Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial... more Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial gas streams such as natural gas, liquefied natural gas and liquefied petroleum gas streams and it has to be removed down to very low concentrations to meet the required specifications. In this article, the propane was contaminated (400–5200 ppmw, part per million by weight) with hydrogen sulfide and carbonyl sulfide and was treated using diethanolamine, 30 mass%, at temperatures 313.15 and 333.15 and the effect of aqueous DEA solution on the separation was investigated.
A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) c... more A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) carbon paste electrode (NiO/NPs/CPE) as high sensitive sensors for voltammetric determination of Nalbuphine (NB). The NiO/NPs was characterized with different methods such as SEM and XRD. The cyclic voltammogram showed an irreversible oxidation peak at 0.57 V (vs. Ag/AgClsat), which corresponded to the oxidation of NB. Compared to common carbon paste electrode, the electrochemical response was greatly improved. The electro-oxidation of NB occurred in a pH-dependent 1e− and 1H + process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions, the voltammetric oxidation peak current of NB showed linear dynamic ranges with a detection limit of 0.5 μM for NB. The novel sensor has been found selective and successfully implemented for the determination of NB in water, serum and urine samples.
Journal of the Taiwan Institute of Chemical Engineers, 2021
Abstract Background Amine degradation products are very important for industrials not only leads ... more Abstract Background Amine degradation products are very important for industrials not only leads to amine losses but also contribute to operational problems such as high corrosion effects. In this research, a new quantitative method has been developed for the analysis of 2-methylaminoethanol (MAE) and tris(2-hydroxyethylethyl)ethylenediamine (THEED) in the diethanolamine solution by cation-exchange chromatography. Methods The mobile phase was optimized for the interference-free determination of THEED and MAE. For THEED, the final composition was included 8 mmol L−1 HNO3 and 15% (v/v) acetonitrile. The linear range of the calibration curve was achieved in the range of 0.5 to 1000 ppm with the correlation coefficient of 0.9998. The relative standard deviation was 3.89%. Also, the mobile phase was optimized for MAE determination. The optimal composition was 1.45 mmol L−1 of HNO3, 0.15 mmol L−1 of 18-crown-6, and 3.4 mmol L−1 of dipicolinic acid. The mobile phase also was contained 0.75% (v/v) of acetonitrile. Significant Findings The linear range of the calibration curve was from 0.1 to 200 ppm with a correlation coefficient of 0.9999, and the relative standard deviation is 0.46%. Very low detection limits including 0.03 and 0.17 ppm were found for MAE and THEED respectively. Acceptable precisions, below the 3.89%, were accomplished by the method. The proposed method was used for the determination of desired compounds in the real natural gas sweetening solution.
International Journal of Thermophysics, 2020
The measure of stability of sulfolane (SFL) in aqueous alkanolamine solution was investigated. Fo... more The measure of stability of sulfolane (SFL) in aqueous alkanolamine solution was investigated. For this purpose, degradation of SFL was experimentally studied under the stripping operational condition ( T = 130 °C). The experiments were divided into two general categories: (1) aqueous solution of SFL with and without presence of oxygen to receive a sense of thermal and oxidative SFL degradation; (2) aqueous solution of MDEA/PZ/SFL loaded by hydrogen sulfide and carbon dioxide (both gas-loadings were set to be 0.25 to roughly make a real condition). The results of the experiments showed that SFL resists thermal degradation, but in the presence of oxygen and temperatures of 130 °C which is in accordance with the desorption operational conditions, it would be prone to degradation to anions such as sulfite, sulfate and thiosulfate.
Journal of Molecular Liquids, 2016
A novel, sensitive, selective and simple method for the direct and quantitative determination of ... more A novel, sensitive, selective and simple method for the direct and quantitative determination of L-tryptophan (Trp) was proposed in this work. Pt/CNTs nanocompoite made by polyol technique, were used to modify ionic liquid carbon paste electrode (CPE) without any treatment to study the electrochemical behaviors of the Trp using cyclic voltammetry (CV) and chronoamperometry (CA) and square wave voltammetry (SWV) methods. The results demonstrated that the 1-butyl-3-methylimidazolium hexafluoro phosphate (([C 4 mim]-[PF 6 ])) Pt/ CNTs modified carbon paste electrode ([C 4 mim]-[PF 6 ]/Pt/CNTs/CPE) exhibited high catalytic activity and analytical performance towards the electro-oxidation of Trp. The linear oxidation response range and limit of detection were found to be 0.1-400 μM and 0.04 μM, respectively. The [C 4 mim]-[PF 6 ]/Pt/CNTs/CPE was successfully applied for the voltammetric determination of Trp in food and pharmaceutical samples.
Journal of Chemical & Engineering Data, 2016
The solubility of hydrogen sulfide in 1,2-ethanediol, 1-propanol, 2-propanol, and 1,2-propanediol... more The solubility of hydrogen sulfide in 1,2-ethanediol, 1-propanol, 2-propanol, and 1,2-propanediol were experimentally measured. Gas concentrations were systematically measured by isochoric saturation method at temperatures from (303.15 to 353.15) K and total pressure from vapor pressure of solvent up to about 1.5 MPa. Results show that H2S dissolves in mentioned organic solvents in order 2-propanol ∼ 1-propanol > 1,2 -propanediol > 1,2-ethanediol. The experimental data were correlated by using (1) the Krichevsky–Ilinskaya (KI) equation and (2) a generic Redlich–Kwong (GRK) cubic equation of state.
Food Analytical Methods, 2015
The electrochemical oxidation of bisphenol A has been studied by CdO nanoparticle ionic liquid ca... more The electrochemical oxidation of bisphenol A has been studied by CdO nanoparticle ionic liquid carbon paste electrode. Cyclic voltammetry, square wave voltammetry, and chronoamperometry were used to investigate the suitability of new sensor for the electrooxidation of bisphenol A in aqueous solution. The electrooxidation of bisphenol A occurs at a potential about 50 mV less positive than with the unmodified carbon paste electrode at pH 7.0. The square wave voltammetry (SWV) peak currents of the electrode increased linearly with the corresponding bisphenol A concentration in the range of 0.3–650 μM with a detection limit of 0.1 μM. The influence of pH value and potential interfering substances on the determination of bisphenol A were studied. Finally, the proposed novel sensor was also examined as a sensitive, high selective, simple, and precise electrochemical sensor for the determination of bisphenol A in food samples.
Journal of Molecular Liquids, 2016
Abstract A highly sensitive sensor based on a carbon paste electrode modified with a CdO nanopart... more Abstract A highly sensitive sensor based on a carbon paste electrode modified with a CdO nanoparticle and 1-methyl-3-butylimidazolium bromide was used for the voltammetric analysis of vitamin C in the presence of nicotin amide adenine dinucleotide. The highly sensitive sensor shows excellent enhancement and electrocatalytic activity towards vitamin C. The variation of pH shows the number of protons is equal to number of electrons for vitamin C electrooxidation. The electrooxidation peak current of vitamin C and nicotin amide adenine dinucleotide increased linearly with their concentration in the ranges of 0.07–480 μmol L− 1 vitamin C and 0.5–700 μmol L− 1 nicotin amide adenine dinucleotide. The limits of detection for vitamin C and nicotin amide adenine dinucleotide were 0.03 μmol L− 1 and 0.1 μmol L− 1, respectively. Simultaneous determination of vitamin C and nicotin amide adenine dinucleotide was investigated by using the square wave voltammetry technique. The proposed sensor showed good stability, sensitivity, selectivity, and reproducibility and can be used for some important food sample analyses.
Journal of Molecular Liquids, 2016
Abstract A highly sensitive and quick voltammetric sensor based on CuFe2O4 nanoparticle/room temp... more Abstract A highly sensitive and quick voltammetric sensor based on CuFe2O4 nanoparticle/room temperature ionic liquids carbon paste electrode (CuFe2O4/ILs/CPE) is proposed for the determination of adrenaline in the biological condition (pH = 7.4). CuFe2O4 are nanoparticles synthesized by co-precipitation method and characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). In continuous, we study application of the CuFe2O4 nanoparticle for the preparation of carbon paste electrode modified with 1,3-dipropylimidazolium bromide as a suitable and high conductive binder. At the best condition (pH 7.4), the peak currents of square wave voltammograms (SWV) of adrenaline increased linearly with its concentration in the ranges of 0.1–400 μM. The detection limit for adrenaline was 0.07 μM. The modified sensor has been successfully applied for the assay of adrenaline in biological and pharmaceutical samples such as urine and injection in comparison with other method.
ABSTRACT Ionic liquid/CdO/NPs carbon paste electrode (IL/CdO/NPs/CPE) has been used as a high sen... more ABSTRACT Ionic liquid/CdO/NPs carbon paste electrode (IL/CdO/NPs/CPE) has been used as a high sensitive sensor for the professional quantitative determination of sudan I in food samples in aqueous solution. In the first step, CdO/NPs synthesis using chemical precipitation method and characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The propose sensor shows a better electrochemical response with lower over-potential and high sensitivity for sudan I compared with unmodified carbon paste electrode using linear sweep voltammetry (LSV). The electro-oxidation of sudan I occurred in a pH-dependent e− and H+ process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions in square wave voltammetry (SWV), the voltammetric oxidation peak current of sudan I showed linear dynamic ranges with a detection limit of 0.05 μM for sudan I. The modified electrode was successfully used for the determination of the analytes in real samples with satisfactory result.
Talanta, 2005
This work introduce an easy and fast continuous cyclic voltammetric technique for the propose mon... more This work introduce an easy and fast continuous cyclic voltammetric technique for the propose monitoring of ultra trace amounts of salbutamol in a flow-injection system. The potential waveform, which consisted of the potential steps for cleaning, stripping and potential ramp, was continuously applied on an Au disk microelectrode (with a radius of 12.5 m). The detection method we propose has some advantages, the greatest of which are: (1) removing oxygen from the analyte solution is no longer necessary, and (2) it is a very fast and appropriate technique for the determination of the drug compound in a wide variety of chromatographic analysis methods. The detection limit for salbutamol was 2.0 × 10 −9 M. The relative standard deviation (R.S.D.) of the proposed technique at 10 ng/mL was 3.5% for 10 runs. The effects of pH of eluent, accumulation potential, sweep rate, and accumulation time on the sensitivity of the method for the determination of the salbutamol were investigated. The proposed method was applied to the determination of salbutamol in pharmaceutical preparation and biological samples.
Microchimica Acta, 2005
This study presents an easy and fast stripping voltammetric detection technique for the determina... more This study presents an easy and fast stripping voltammetric detection technique for the determination of amikacin sulfate in a flow-injection system. For a very sensitive determination, the currents were integrated for a whole potential scan range including oxidation and reduction of the gold surface electrode. The potential waveform, which consisted of potential steps for cleaning, stripping and potential ramp, was continuously applied to a gold disk ultramicroelectrode (with a diameter of 50 mm). The greatest advantages of the proposed detection method are a) very low detection limit (picomolar level), b) removing oxygen from the test solution is not necessary, c) very fast and appropriate for monitoring drug compounds in a wide variety of chromatographic analysis methods. The detection limit for amikacin sulfate was 2.0Â10 À11 M ($15 pg mL À1), and the relative standard deviation for 10 determinations of 1.0 ng mL À1 of amikacin was 3.2%. The effects of scan rate, accumulation potential, accumulation time and pH of eluent on the performance of the method were investigated. The results were used for the determination of amikacin sulfate in pharmaceutical preparations.
Journal of the Brazilian Chemical Society, 2013
A eletrooxidação da cisteamina (CA) foi estudada por eletrodos de pasta de nanotubos de carbono m... more A eletrooxidação da cisteamina (CA) foi estudada por eletrodos de pasta de nanotubos de carbono modificados com ácido 3,4-diidroxicinâmico (3,4-DHCA) usando voltametria cíclica, cronoamperometria e voltametria de varredura linear. Usando o eletrodo modificado, a cinética de eletrooxidação da CA foi consideravelmente intensificada através da redução do potencial anódico por meio de uma reação catalítica. O mecanismo de comportamento eletroquímico da CA na superfície do eletrodo modificado foi analisado por vários métodos eletroquímicos, na presença de mediador. O eletrodo modificado preparado apresentou respostas voltamétricas com alta sensibilidade para CA, o que o torna muito adequado para a detecção de CA em quantidades de traço. Um intervalo dinâmico linear de 0,25-400 µmol L −1 para a CA foi obtida em solução tamponada com pH 7,0. O limite de detecção foi de 0,09 µmol L −1. The electrooxidation of cysteamine (CA) was studied by modified carbon nanotubes paste electrode in the presence of 3,4-dihydroxycinnamic acid (3,4-DHCA) using cyclic voltammetry, chronoamperometry and linear sweep voltammetry. Using the modified electrode, the kinetics of CA electrooxidation was considerably enhanced by lowering the anodic over-potential through a catalytic fashion. The mechanism of CA electrochemical behavior at the modified electrode surface was analyzed by various electrochemical methods in the presence of mediator. The prepared modified electrode showed voltammetric responses with high sensitivity for CA, making it very suitable for the detection of CA at trace levels. A linear dynamic range of 0.25-400 µmol L −1 for CA was obtained in buffered solutions with pH 7.0. The limit of detection was 0.09 µmol L −1 .
Journal of Pharmaceutical Sciences, 2007
In this work a novel method for the determination of nortriptyline in flowinjection systems has b... more In this work a novel method for the determination of nortriptyline in flowinjection systems has been developed. The proposed method was used for the fast determination of nortriptyline in its pharmaceutical formulations. The developed technique is very simple, precise, accurate, time saving, and economical, compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance obtained at pH value of 2, scan rate value of 30 V/s, accumulation potential of 400 mV, and accumulation time of 0.5 s. The proposed method has some advantages over other reported methods such as, no need for the removal of oxygen from the test solution, a subnanomolar detection limit, and finally the method is sufficiently fast for the determination of any such compound, in a wide variety of chromatographic methods. The potential waveform, consisting of the potential steps for cleaning, accumulation and potential ramp of analyte, was continuously applied on an Au disk microelectrode (12.5 mm in radius). The detection limit of the method was 2.0 Â 10 À11 M. The relative standard deviation of the method at 1.2 Â 10 À8 M was 2.1% for eight runs.
Analytical Sciences, 2011
Two amino acids, L-cysteine and tryptophan, could be simultaneously determined in an aqueous solu... more Two amino acids, L-cysteine and tryptophan, could be simultaneously determined in an aqueous solution (pH 6.0) using a carbon nanotube paste electrode (CNPE) modified with p-aminophenol as a mediator. The results indicate that the electrode is efficient in terms of its electrocatalytic activity for the oxidation of L-cysteine, leading to an overpotential reduced by more than 550 mV. Using differential pulse voltammetry, we could measure L-cysteine and tryptophan in one mixture independently from each other by a potential difference of about 600 mV. Electrochemical techniques are used to determine the diffusion coefficients, kinetic parameters such as electron transfer coefficient, and the rates of electro-oxidation of L-cysteine at the surface of the p-aminophenol-modified CNPE. The peak current is found to depend linearly on L-cysteine and tryptophan concentrations within the ranges of 0.5-100 μmol L-1 L-cysteine and 10.0-300 μmol L-1 tryptophan. The detection limits for L-cysteine and tryptophan are found to be 0.3 and 5.7 μmol L-1 , respectively. The proposed method is also used for the determination of L-cysteine and tryptophan in urine, river water, blood plasma, and serum samples using standard addition methods.
Bulletin of the Korean Chemical Society, 2005
Bis(2-methylbenzaldehyde)butane-2,3-dihydrazone(TDSB) was used as new N-N Schiff's base which pla... more Bis(2-methylbenzaldehyde)butane-2,3-dihydrazone(TDSB) was used as new N-N Schiff's base which plays the role of an excellent ion carrier in the construction of a La(III) membrane sensor. The best performance was obtained with a membrane containing, 30% poly(vinyl chloride), 60% benzyl acetate, 6% TDSB and 4% sodium tetraphenyl borate. This sensor reveals a very good selectivity towards La(III) ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The proposed electrode exhibits a Nernstian behavior (with slope of 19.8 mV per decade) over a wide concentration range (1.0 × 10 −5-1.0 × 10 −1 M). The detection limit of the sensor is 7.0 × 10 −6 M. It has a very short response time, in the whole concentration range (~5 s), and can be used for at least twelve weeks in the pH range of 3.0-9.4. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a La(III) solution, with EDTA. It was also successfully applied in the determination of fluoride ions in three mouth wash preparations.
Bulletin of the Korean Chemical Society, 2004
A highly selective membrane electrode based on1,3,5-triphenylpyrylium perchlorate (TPPP) is prese... more A highly selective membrane electrode based on1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of-29.7 mV per decade. The working concentration ranges of the electrode is 1.0 x 10-1-6.3 x 10-6 M with a detection limit of 4.0 x 10-6 M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate.
Journal of Solution Chemistry
Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial... more Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial gas streams such as natural gas, liquefied natural gas and liquefied petroleum gas streams and it has to be removed down to very low concentrations to meet the required specifications. In this article, the propane was contaminated (400–5200 ppmw, part per million by weight) with hydrogen sulfide and carbonyl sulfide and was treated using diethanolamine, 30 mass%, at temperatures 313.15 and 333.15 and the effect of aqueous DEA solution on the separation was investigated.
A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) c... more A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) carbon paste electrode (NiO/NPs/CPE) as high sensitive sensors for voltammetric determination of Nalbuphine (NB). The NiO/NPs was characterized with different methods such as SEM and XRD. The cyclic voltammogram showed an irreversible oxidation peak at 0.57 V (vs. Ag/AgClsat), which corresponded to the oxidation of NB. Compared to common carbon paste electrode, the electrochemical response was greatly improved. The electro-oxidation of NB occurred in a pH-dependent 1e− and 1H + process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions, the voltammetric oxidation peak current of NB showed linear dynamic ranges with a detection limit of 0.5 μM for NB. The novel sensor has been found selective and successfully implemented for the determination of NB in water, serum and urine samples.
Journal of Solution Chemistry
Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial... more Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial gas streams such as natural gas, liquefied natural gas and liquefied petroleum gas streams and it has to be removed down to very low concentrations to meet the required specifications. In this article, the propane was contaminated (400–5200 ppmw, part per million by weight) with hydrogen sulfide and carbonyl sulfide and was treated using diethanolamine, 30 mass%, at temperatures 313.15 and 333.15 and the effect of aqueous DEA solution on the separation was investigated.
A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) c... more A b s t r a c t In this study we report synthesis and application of NiO nanoparticle (NiO/NPs) carbon paste electrode (NiO/NPs/CPE) as high sensitive sensors for voltammetric determination of Nalbuphine (NB). The NiO/NPs was characterized with different methods such as SEM and XRD. The cyclic voltammogram showed an irreversible oxidation peak at 0.57 V (vs. Ag/AgClsat), which corresponded to the oxidation of NB. Compared to common carbon paste electrode, the electrochemical response was greatly improved. The electro-oxidation of NB occurred in a pH-dependent 1e− and 1H + process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions, the voltammetric oxidation peak current of NB showed linear dynamic ranges with a detection limit of 0.5 μM for NB. The novel sensor has been found selective and successfully implemented for the determination of NB in water, serum and urine samples.
Journal of the Taiwan Institute of Chemical Engineers, 2021
Abstract Background Amine degradation products are very important for industrials not only leads ... more Abstract Background Amine degradation products are very important for industrials not only leads to amine losses but also contribute to operational problems such as high corrosion effects. In this research, a new quantitative method has been developed for the analysis of 2-methylaminoethanol (MAE) and tris(2-hydroxyethylethyl)ethylenediamine (THEED) in the diethanolamine solution by cation-exchange chromatography. Methods The mobile phase was optimized for the interference-free determination of THEED and MAE. For THEED, the final composition was included 8 mmol L−1 HNO3 and 15% (v/v) acetonitrile. The linear range of the calibration curve was achieved in the range of 0.5 to 1000 ppm with the correlation coefficient of 0.9998. The relative standard deviation was 3.89%. Also, the mobile phase was optimized for MAE determination. The optimal composition was 1.45 mmol L−1 of HNO3, 0.15 mmol L−1 of 18-crown-6, and 3.4 mmol L−1 of dipicolinic acid. The mobile phase also was contained 0.75% (v/v) of acetonitrile. Significant Findings The linear range of the calibration curve was from 0.1 to 200 ppm with a correlation coefficient of 0.9999, and the relative standard deviation is 0.46%. Very low detection limits including 0.03 and 0.17 ppm were found for MAE and THEED respectively. Acceptable precisions, below the 3.89%, were accomplished by the method. The proposed method was used for the determination of desired compounds in the real natural gas sweetening solution.
International Journal of Thermophysics, 2020
The measure of stability of sulfolane (SFL) in aqueous alkanolamine solution was investigated. Fo... more The measure of stability of sulfolane (SFL) in aqueous alkanolamine solution was investigated. For this purpose, degradation of SFL was experimentally studied under the stripping operational condition ( T = 130 °C). The experiments were divided into two general categories: (1) aqueous solution of SFL with and without presence of oxygen to receive a sense of thermal and oxidative SFL degradation; (2) aqueous solution of MDEA/PZ/SFL loaded by hydrogen sulfide and carbon dioxide (both gas-loadings were set to be 0.25 to roughly make a real condition). The results of the experiments showed that SFL resists thermal degradation, but in the presence of oxygen and temperatures of 130 °C which is in accordance with the desorption operational conditions, it would be prone to degradation to anions such as sulfite, sulfate and thiosulfate.
Journal of Molecular Liquids, 2016
A novel, sensitive, selective and simple method for the direct and quantitative determination of ... more A novel, sensitive, selective and simple method for the direct and quantitative determination of L-tryptophan (Trp) was proposed in this work. Pt/CNTs nanocompoite made by polyol technique, were used to modify ionic liquid carbon paste electrode (CPE) without any treatment to study the electrochemical behaviors of the Trp using cyclic voltammetry (CV) and chronoamperometry (CA) and square wave voltammetry (SWV) methods. The results demonstrated that the 1-butyl-3-methylimidazolium hexafluoro phosphate (([C 4 mim]-[PF 6 ])) Pt/ CNTs modified carbon paste electrode ([C 4 mim]-[PF 6 ]/Pt/CNTs/CPE) exhibited high catalytic activity and analytical performance towards the electro-oxidation of Trp. The linear oxidation response range and limit of detection were found to be 0.1-400 μM and 0.04 μM, respectively. The [C 4 mim]-[PF 6 ]/Pt/CNTs/CPE was successfully applied for the voltammetric determination of Trp in food and pharmaceutical samples.
Journal of Chemical & Engineering Data, 2016
The solubility of hydrogen sulfide in 1,2-ethanediol, 1-propanol, 2-propanol, and 1,2-propanediol... more The solubility of hydrogen sulfide in 1,2-ethanediol, 1-propanol, 2-propanol, and 1,2-propanediol were experimentally measured. Gas concentrations were systematically measured by isochoric saturation method at temperatures from (303.15 to 353.15) K and total pressure from vapor pressure of solvent up to about 1.5 MPa. Results show that H2S dissolves in mentioned organic solvents in order 2-propanol ∼ 1-propanol > 1,2 -propanediol > 1,2-ethanediol. The experimental data were correlated by using (1) the Krichevsky–Ilinskaya (KI) equation and (2) a generic Redlich–Kwong (GRK) cubic equation of state.
Food Analytical Methods, 2015
The electrochemical oxidation of bisphenol A has been studied by CdO nanoparticle ionic liquid ca... more The electrochemical oxidation of bisphenol A has been studied by CdO nanoparticle ionic liquid carbon paste electrode. Cyclic voltammetry, square wave voltammetry, and chronoamperometry were used to investigate the suitability of new sensor for the electrooxidation of bisphenol A in aqueous solution. The electrooxidation of bisphenol A occurs at a potential about 50 mV less positive than with the unmodified carbon paste electrode at pH 7.0. The square wave voltammetry (SWV) peak currents of the electrode increased linearly with the corresponding bisphenol A concentration in the range of 0.3–650 μM with a detection limit of 0.1 μM. The influence of pH value and potential interfering substances on the determination of bisphenol A were studied. Finally, the proposed novel sensor was also examined as a sensitive, high selective, simple, and precise electrochemical sensor for the determination of bisphenol A in food samples.
Journal of Molecular Liquids, 2016
Abstract A highly sensitive sensor based on a carbon paste electrode modified with a CdO nanopart... more Abstract A highly sensitive sensor based on a carbon paste electrode modified with a CdO nanoparticle and 1-methyl-3-butylimidazolium bromide was used for the voltammetric analysis of vitamin C in the presence of nicotin amide adenine dinucleotide. The highly sensitive sensor shows excellent enhancement and electrocatalytic activity towards vitamin C. The variation of pH shows the number of protons is equal to number of electrons for vitamin C electrooxidation. The electrooxidation peak current of vitamin C and nicotin amide adenine dinucleotide increased linearly with their concentration in the ranges of 0.07–480 μmol L− 1 vitamin C and 0.5–700 μmol L− 1 nicotin amide adenine dinucleotide. The limits of detection for vitamin C and nicotin amide adenine dinucleotide were 0.03 μmol L− 1 and 0.1 μmol L− 1, respectively. Simultaneous determination of vitamin C and nicotin amide adenine dinucleotide was investigated by using the square wave voltammetry technique. The proposed sensor showed good stability, sensitivity, selectivity, and reproducibility and can be used for some important food sample analyses.
Journal of Molecular Liquids, 2016
Abstract A highly sensitive and quick voltammetric sensor based on CuFe2O4 nanoparticle/room temp... more Abstract A highly sensitive and quick voltammetric sensor based on CuFe2O4 nanoparticle/room temperature ionic liquids carbon paste electrode (CuFe2O4/ILs/CPE) is proposed for the determination of adrenaline in the biological condition (pH = 7.4). CuFe2O4 are nanoparticles synthesized by co-precipitation method and characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). In continuous, we study application of the CuFe2O4 nanoparticle for the preparation of carbon paste electrode modified with 1,3-dipropylimidazolium bromide as a suitable and high conductive binder. At the best condition (pH 7.4), the peak currents of square wave voltammograms (SWV) of adrenaline increased linearly with its concentration in the ranges of 0.1–400 μM. The detection limit for adrenaline was 0.07 μM. The modified sensor has been successfully applied for the assay of adrenaline in biological and pharmaceutical samples such as urine and injection in comparison with other method.
ABSTRACT Ionic liquid/CdO/NPs carbon paste electrode (IL/CdO/NPs/CPE) has been used as a high sen... more ABSTRACT Ionic liquid/CdO/NPs carbon paste electrode (IL/CdO/NPs/CPE) has been used as a high sensitive sensor for the professional quantitative determination of sudan I in food samples in aqueous solution. In the first step, CdO/NPs synthesis using chemical precipitation method and characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The propose sensor shows a better electrochemical response with lower over-potential and high sensitivity for sudan I compared with unmodified carbon paste electrode using linear sweep voltammetry (LSV). The electro-oxidation of sudan I occurred in a pH-dependent e− and H+ process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions in square wave voltammetry (SWV), the voltammetric oxidation peak current of sudan I showed linear dynamic ranges with a detection limit of 0.05 μM for sudan I. The modified electrode was successfully used for the determination of the analytes in real samples with satisfactory result.
Talanta, 2005
This work introduce an easy and fast continuous cyclic voltammetric technique for the propose mon... more This work introduce an easy and fast continuous cyclic voltammetric technique for the propose monitoring of ultra trace amounts of salbutamol in a flow-injection system. The potential waveform, which consisted of the potential steps for cleaning, stripping and potential ramp, was continuously applied on an Au disk microelectrode (with a radius of 12.5 m). The detection method we propose has some advantages, the greatest of which are: (1) removing oxygen from the analyte solution is no longer necessary, and (2) it is a very fast and appropriate technique for the determination of the drug compound in a wide variety of chromatographic analysis methods. The detection limit for salbutamol was 2.0 × 10 −9 M. The relative standard deviation (R.S.D.) of the proposed technique at 10 ng/mL was 3.5% for 10 runs. The effects of pH of eluent, accumulation potential, sweep rate, and accumulation time on the sensitivity of the method for the determination of the salbutamol were investigated. The proposed method was applied to the determination of salbutamol in pharmaceutical preparation and biological samples.
Microchimica Acta, 2005
This study presents an easy and fast stripping voltammetric detection technique for the determina... more This study presents an easy and fast stripping voltammetric detection technique for the determination of amikacin sulfate in a flow-injection system. For a very sensitive determination, the currents were integrated for a whole potential scan range including oxidation and reduction of the gold surface electrode. The potential waveform, which consisted of potential steps for cleaning, stripping and potential ramp, was continuously applied to a gold disk ultramicroelectrode (with a diameter of 50 mm). The greatest advantages of the proposed detection method are a) very low detection limit (picomolar level), b) removing oxygen from the test solution is not necessary, c) very fast and appropriate for monitoring drug compounds in a wide variety of chromatographic analysis methods. The detection limit for amikacin sulfate was 2.0Â10 À11 M ($15 pg mL À1), and the relative standard deviation for 10 determinations of 1.0 ng mL À1 of amikacin was 3.2%. The effects of scan rate, accumulation potential, accumulation time and pH of eluent on the performance of the method were investigated. The results were used for the determination of amikacin sulfate in pharmaceutical preparations.
Journal of the Brazilian Chemical Society, 2013
A eletrooxidação da cisteamina (CA) foi estudada por eletrodos de pasta de nanotubos de carbono m... more A eletrooxidação da cisteamina (CA) foi estudada por eletrodos de pasta de nanotubos de carbono modificados com ácido 3,4-diidroxicinâmico (3,4-DHCA) usando voltametria cíclica, cronoamperometria e voltametria de varredura linear. Usando o eletrodo modificado, a cinética de eletrooxidação da CA foi consideravelmente intensificada através da redução do potencial anódico por meio de uma reação catalítica. O mecanismo de comportamento eletroquímico da CA na superfície do eletrodo modificado foi analisado por vários métodos eletroquímicos, na presença de mediador. O eletrodo modificado preparado apresentou respostas voltamétricas com alta sensibilidade para CA, o que o torna muito adequado para a detecção de CA em quantidades de traço. Um intervalo dinâmico linear de 0,25-400 µmol L −1 para a CA foi obtida em solução tamponada com pH 7,0. O limite de detecção foi de 0,09 µmol L −1. The electrooxidation of cysteamine (CA) was studied by modified carbon nanotubes paste electrode in the presence of 3,4-dihydroxycinnamic acid (3,4-DHCA) using cyclic voltammetry, chronoamperometry and linear sweep voltammetry. Using the modified electrode, the kinetics of CA electrooxidation was considerably enhanced by lowering the anodic over-potential through a catalytic fashion. The mechanism of CA electrochemical behavior at the modified electrode surface was analyzed by various electrochemical methods in the presence of mediator. The prepared modified electrode showed voltammetric responses with high sensitivity for CA, making it very suitable for the detection of CA at trace levels. A linear dynamic range of 0.25-400 µmol L −1 for CA was obtained in buffered solutions with pH 7.0. The limit of detection was 0.09 µmol L −1 .
Journal of Pharmaceutical Sciences, 2007
In this work a novel method for the determination of nortriptyline in flowinjection systems has b... more In this work a novel method for the determination of nortriptyline in flowinjection systems has been developed. The proposed method was used for the fast determination of nortriptyline in its pharmaceutical formulations. The developed technique is very simple, precise, accurate, time saving, and economical, compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance obtained at pH value of 2, scan rate value of 30 V/s, accumulation potential of 400 mV, and accumulation time of 0.5 s. The proposed method has some advantages over other reported methods such as, no need for the removal of oxygen from the test solution, a subnanomolar detection limit, and finally the method is sufficiently fast for the determination of any such compound, in a wide variety of chromatographic methods. The potential waveform, consisting of the potential steps for cleaning, accumulation and potential ramp of analyte, was continuously applied on an Au disk microelectrode (12.5 mm in radius). The detection limit of the method was 2.0 Â 10 À11 M. The relative standard deviation of the method at 1.2 Â 10 À8 M was 2.1% for eight runs.
Analytical Sciences, 2011
Two amino acids, L-cysteine and tryptophan, could be simultaneously determined in an aqueous solu... more Two amino acids, L-cysteine and tryptophan, could be simultaneously determined in an aqueous solution (pH 6.0) using a carbon nanotube paste electrode (CNPE) modified with p-aminophenol as a mediator. The results indicate that the electrode is efficient in terms of its electrocatalytic activity for the oxidation of L-cysteine, leading to an overpotential reduced by more than 550 mV. Using differential pulse voltammetry, we could measure L-cysteine and tryptophan in one mixture independently from each other by a potential difference of about 600 mV. Electrochemical techniques are used to determine the diffusion coefficients, kinetic parameters such as electron transfer coefficient, and the rates of electro-oxidation of L-cysteine at the surface of the p-aminophenol-modified CNPE. The peak current is found to depend linearly on L-cysteine and tryptophan concentrations within the ranges of 0.5-100 μmol L-1 L-cysteine and 10.0-300 μmol L-1 tryptophan. The detection limits for L-cysteine and tryptophan are found to be 0.3 and 5.7 μmol L-1 , respectively. The proposed method is also used for the determination of L-cysteine and tryptophan in urine, river water, blood plasma, and serum samples using standard addition methods.