Analytical chemistry
Maryam Ebrahimi; Hadi Beitollahi
Abstract
This study reported the electrochemical sensor for sensitive determination of methionine based on CuO nanoflowers (CuO NFs) supported on glassy carbon electrode (GCE). Therefore, we utilized cyclic voltammetry (CV), chronoamperometry (CHA) as well as differential pulse voltammetry (DPV) for characterizing ...
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This study reported the electrochemical sensor for sensitive determination of methionine based on CuO nanoflowers (CuO NFs) supported on glassy carbon electrode (GCE). Therefore, we utilized cyclic voltammetry (CV), chronoamperometry (CHA) as well as differential pulse voltammetry (DPV) for characterizing the sensor performance. This CuO NFs/GCE has been found to have very good electrochemical catalytic activity toward methionine oxidation. The oxidation overpotential of methionine decreased significantly and its oxidation peak current increased dramatically at CuO NFs/GCE. Moreover, the sensor showed a linear response for detecting methionine in the broad ranges from 1.0-300.0 µM with a low limit of detection (LOD) equal to 0.3 µM. Finally, we employed CuO NFs/GCE as a highly sensitive tool to analyze methionine in real sample (urine).
Analytical chemistry
Hadi Beitollahi; Sajedeh Salari
Abstract
The present research presented a novel modification approach for modifying a glassy carbon electrode on the basis of the Ce3+/NiO hexagonal nanoparticles (Ce3+/NiO hexagonal NPs/GCE). In so doing, we devised the new modified electrode for using as one of the sensitive sensors for detecting the trace ...
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The present research presented a novel modification approach for modifying a glassy carbon electrode on the basis of the Ce3+/NiO hexagonal nanoparticles (Ce3+/NiO hexagonal NPs/GCE). In so doing, we devised the new modified electrode for using as one of the sensitive sensors for detecting the trace amounts of hydrochlorothiazide. Moreover, it is an acceptable electrocatalyst for catalytic oxidation of hydrochlorothiazide by shifting the overpotential toward less positive potential and enhancing catalytic current in comparison to the bare GCE. In a concentration range 0.1 to 700.0 μM in a phosphate buffer solution (PBS) at a pH of 7.0, the responses were linear and hydrochlorothiazide detection limit for this method was 0.03 μM (S/N=3). Furthermore, this sensor successfully detected hydrochlorothiazide in hydrochlorothiazide tablets and urine samples with satisfactory recovery ranges, indicating a promising application in biological samples, pharmaceutical compounds analysis and clinical diagnosis.
Analytical chemistry
Swati Sinha; Tapan Kumar Nailwal
Abstract
Oroxylum indicum is an important Ayurvedic medicinal plant used in medicinal formulations to treat many diseases. In this research, an effective, sensitive, reliable, cost effective and comprehensive assessment of quality of Oroxylum indicum has been developed based on high performance liquid chromatography ...
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Oroxylum indicum is an important Ayurvedic medicinal plant used in medicinal formulations to treat many diseases. In this research, an effective, sensitive, reliable, cost effective and comprehensive assessment of quality of Oroxylum indicum has been developed based on high performance liquid chromatography (HPLC) fingerprint analysis combined with the quantitative analysis of multi-components by a single marker (QAMS) method. The contents of four components i.e., Scutellarin, Hispidulin, Baicalein and Biochanina-A, has been determined, simultaneously, and Baicalein is used as internal reference standard. It was established that there is no major difference between the QAMS method and the traditional external standard method (ESM) (RSD<2.00%). This signifies that QAMS is a consistent and expedient method for the content determination of multiple components, particularly when there is non-availability of multiple reference standards. This method was also validated in terms of linearity, precision, stability, recovery and reproducibility. Hence it can be effectively applied for quality assessment of Oroxylum indicum in various Ayurvedic formulations.
Analytical chemistry
Kirsh Irina Anatolyevna; Beznaeva Olga Vladimirovna; Bannikova Olga Anatolyevnaa; Gubanova Marina Ivanovna; Tveritnikova Isabella Sergeevna; Romanova Valentina Alexandrovna; Novikov Maxim Nikolaevich
Abstract
Nowadays, environmental protection has become a global issue due to the sharp increase of waste as a result of the rapid and almost uncontrollable growth in the consumption of synthetic plastics in many sectors of the economy. The issue of the disposal of the products is therefore becoming increasingly ...
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Nowadays, environmental protection has become a global issue due to the sharp increase of waste as a result of the rapid and almost uncontrollable growth in the consumption of synthetic plastics in many sectors of the economy. The issue of the disposal of the products is therefore becoming increasingly important. The creation of biodegradable materials is one of the most acceptable ways to solve the issue, along with the development and research of new biodegradable polymer materials. This study approached the physicochemical properties and the decomposition time of biodegradable polymer compositions obtained by the impact of the ultrasonic treatment on their melts under the laboratory and experimental industrial conditions. The results indicated that The ultrasonic treatment of polymer composite materials (PCMs), based on starch and polyethylene, could lead to the increase in their physicomechanical properties by 1.5-2 times, compared with the control samples, which is associated with the uniform distribution of the filler in the polymer matrix.
Analytical chemistry
Kirsh Irina Anatolyevna; Frolova Yulia Vladimirovna; Beznaeva Olga Vladimirovna; Bannikova Olga Anatolyevna; Gubanova Marina Ivanovna; Kondratova Tamara Alexandrovna
Abstract
Ensuring the microbiological safety of food products is a problem currently at issue. The use of antimicrobial packaging materials is a way of solving the problem. Accordingly, the aim of this work was to create packaging materials based on polyethylene (PE) and silver nanoparticles (Ag-NPs) using the ...
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Ensuring the microbiological safety of food products is a problem currently at issue. The use of antimicrobial packaging materials is a way of solving the problem. Accordingly, the aim of this work was to create packaging materials based on polyethylene (PE) and silver nanoparticles (Ag-NPs) using the ultrasonic treatment of the melt to obtain antimicrobial materials that provide an extended shelf life of packaged food products. Materials based on PE were obtained with Ag-NPs concentrations of 0.5%, 1.0%, 2.0% and 5.0% with and without ultrasonic treatment of melts. Standard methods for studying rheological, physicomechanical, antimicrobial properties and sanitary-chemical indicators of materials were used in the article. It was found that ultrasonic treatment increases the melt flow and contributes to the production of materials with the uniform distribution of additives. The Ag-NPs content from 1.0% and higher in the contents of the material provides antimicrobial properties. The prolongation of the shelf life of the food product, stored in a material based on PE and Ag-NPs 2.0%, was established. In the study of oxygen and water vapour permeability of polymer compositions based on PE and Ag-NPs, it was found that the introduction of a filler increased vapour permeability by about 8-10%, compared with the control samples. The development of polymer composite materials (PCM) with antimicrobial properties and degradability was carried out.
Analytical chemistry
Maryam Pirozmand; Azizallah Nezhadali; Mahmood Payehghadr; Lotfali Saghatforoush
Abstract
A novel chemically modified carbon paste electrode (CMCPE) impregnated with 4′-(4-chlorophenyl)-2,2′:6′,2′′-terpyridine ligand was prepared and applied for voltammetric determination of Cd2+ ion in petrochemical samples. The effects of pH, ligand amount and supporting electrolyte ...
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A novel chemically modified carbon paste electrode (CMCPE) impregnated with 4′-(4-chlorophenyl)-2,2′:6′,2′′-terpyridine ligand was prepared and applied for voltammetric determination of Cd2+ ion in petrochemical samples. The effects of pH, ligand amount and supporting electrolyte on the selective adsorption properties for the Cd2+ ion were explored. The sensor displayed substantially good resistance against interfering agents. In the presence of a large excess of Na+, K+, Ca2+, Mg2+ and Pb2+, the adsorption capacity for Cd2+ was slightly changed, suggesting the high selectivity of CMCPE for Cd2+ions. The parameters controlling the response of the electrode were investigated. The limit of detection (LOD) and relative standard deviation (n = 5) were obtained by 3.77 ng/Land 0.45%, respectively. The preconcentration procedure revealed a linear curve within the concentration range of 4 – 3000 ng/L and a good linearity with squared correlation coefficient of (R2) 0.9988 was achieved. The CV was run starting from –1.5 V to 0.0 V and back (Scan rate: 100 mV/s). The best ratio of the Cd2+-Ligand in carbon paste was 8% (w/w) for a good detection of Cd2+ ions. Optimum pH for maximum adsorption was 4.0 ±0.2. All the instrumental parameters involved in the analytical procedure were optimized. The study was accomplished in Britton–Robinson (B-R) buffer solution of 2 ng/mL Cd2+ ions. The optimal values of scan rate, pulse amplitude, pulse time, voltage step, voltage step time, deposition potential and deposition time were obtained 100 mV/s, 0.20 V, 0.04 s, 0.005 V, 1.2 s, – 0.95 V and 150 s, respectively.
Analytical chemistry
Mahmood Payehghadr; Yeganeh Taherkhani; Abbas Maleki; Farzaneh Nourifard
Abstract
A molecularly imprinted polymer modified carbon paste electrode for determination of methocarbamol drug was constructed and used in aqueous and biological samples. The MIP was synthesized by methacrylic acid as monomer, azobis isobutyronitrile as initiator and methocarbamol as analyte with precipitation ...
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A molecularly imprinted polymer modified carbon paste electrode for determination of methocarbamol drug was constructed and used in aqueous and biological samples. The MIP was synthesized by methacrylic acid as monomer, azobis isobutyronitrile as initiator and methocarbamol as analyte with precipitation polymerization process. The oxidation voltamograms of analyte using MIP modified nickel ferrite catalyst electrode with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) by potentiostat – galvanostat device were obtained. The methocarbamol drug has amine groups in its structure, thus it is affected by the medium pH, and the effect of this factor on the electrode response was investigated. In optimum conditions, 4% MIP, 8% nanoparticles catalyst, and pH 3, 1.0×10-5M standard solution of methocarbamol was prepared and studied by DPV and CV mode. The dynamic calibration ranges, 3.0×10-8 - 3.0×10-6 M, detection limit of the method 1.3×10-8 M and RSD of the method for two measurements 3.33% and 1.00% was obtained.
Analytical chemistry
Bilal Yilmaz; Nurullah Yilmaz
Abstract
This research study discusses two rapid, sensitive and specific methods for simultaneous determination of rosuvastatin (ROS) and amlodipine (AML) in pharmaceutical preparations using the differential pulse voltammetry (DPV) and high-performance liquid chromatography (HPLC). Electrochemical behavior and ...
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This research study discusses two rapid, sensitive and specific methods for simultaneous determination of rosuvastatin (ROS) and amlodipine (AML) in pharmaceutical preparations using the differential pulse voltammetry (DPV) and high-performance liquid chromatography (HPLC). Electrochemical behavior and simultaneous voltammetric determination of ROS and AML were investigated using the platinum disk electrode. HPLC was also developed for the comparison. The flow rate of the mobile phase was 1.0 mL/min and all the detections were carried out at 225 nm using the UV detection. The calibration curve was established over the concentration range of 0.5-4 mg/mLfor DPV and 0.1-2 mg/mLfor HPLC. The intra- and inter-day relative standard deviation was less than 2.96 and 3.07% for DPV and HPLC, respectively. Limits of quantification were determined as 0.21 and 0.06 mg/mLfor DPV and HPLC, respectively. Both the drugs along with their degradation products were separated in less than 8 min. No interference was found from tablet excipients at the selected assay conditions. The methods were applied for the quality control of the commercial ROS and AML drug.
Analytical chemistry
Amir Yaghoubi Nezhad; Atieh Soltantabar Shahabedini; Husam Ali
Abstract
The entry of drugs produced into nature causes many environmental problems, which shows the importance of controlling and measuring these drugs more than before. Due to the importance of this measurement, some environmental laboratories are dedicated for improving a method to determine small amounts ...
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The entry of drugs produced into nature causes many environmental problems, which shows the importance of controlling and measuring these drugs more than before. Due to the importance of this measurement, some environmental laboratories are dedicated for improving a method to determine small amounts of fluoxetine as pollutant in water and a biological sample. In this research study, new techniques were applied for solid phase extraction of insignificant amounts of fluoxetine in water samples by carbon nanotubes and its measurement with ultraviolet-visible spectroscopy in biological samples. These techniques are two-phase systems in which donor phases are fluoxetine-containing aqueous samples and acceptor phases are amino-functionalized carbon nanotubes. The experiments were carried out in two stages of extraction from desolate water samples of fluoxetine using methanol as solvent and the desolate samples were taken to UV-Vis spectrophotometer for further analysis. This method is inexpensive, simple and fast, and is consistent with many of the existing machine methods. Extraction parameters such as the effect of desolating organic solvents, pH of donor and acceptor phases, extraction time, desolation time, mixing speed, volume of donor phase and surfactant effect were optimized and quantitative investigations and measurements were done under optimum conditions. The aforementioned techniques have many advantages including short extraction time, low consumption of organic solvents, deleting the effect of previous experiments, low detection limit, and high concentration factor. Concentration factor and detection limit for fluoxetine were found to be 14.3 and 13.6 μg, respectively.
Analytical chemistry
Atieh Soltantabar Shahabedini; Mohammad Alinezhad Chamazketi; Amir Yaghoubi Nezhad; Seyed Mojtaba Mostafavi
Abstract
SDS removal is an important process in proteomics after protein digestion. The research study evaluated an offline SDS removal, as well as, the capability of the offline electrophoretic system for SDS removal. Tyr-Tyr-Tyr, Glu-Val-Phe, and Bradykinin were three peptides to be tested at the presence of ...
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SDS removal is an important process in proteomics after protein digestion. The research study evaluated an offline SDS removal, as well as, the capability of the offline electrophoretic system for SDS removal. Tyr-Tyr-Tyr, Glu-Val-Phe, and Bradykinin were three peptides to be tested at the presence of the SDS. The electrophoretic system included a 20 µL glass micropipette containing sample which was immersed into acetonitrile at one end and hydrogel at another end. The SDS removal was driven by applying voltage to the system and after removal, the sample inside micropipette can be collected for liquid chromatography, capillary electrophoresis, and mass spectrometry.
Analytical chemistry
Morteza Motahharinia; Hassan Ali Zamani; Hassan Karimi Maleh
Abstract
In the present study, ZnO nanoparticle doped with Pd (ZnO-Pd) using one simple chemical precipitation method has been synthesized and characterized by different characterization methods. The synthesized nanoparticle presented a nano-size spherical shape with d
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In the present study, ZnO nanoparticle doped with Pd (ZnO-Pd) using one simple chemical precipitation method has been synthesized and characterized by different characterization methods. The synthesized nanoparticle presented a nano-size spherical shape with d
Analytical chemistry
Esmat Shojaei; Mahboubeh Masrournia; Ali Beyramabadi; Hossein Behmadi
Abstract
Chromium has been widely applied in industrial of pigment, stainless steel and electroplating and tanning procedure that enters the water sources. In this work, a simple and reproducible potentiometric sensor was developed for the determination of Cr(III) ions in real solid samples. For this purpose, ...
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Chromium has been widely applied in industrial of pigment, stainless steel and electroplating and tanning procedure that enters the water sources. In this work, a simple and reproducible potentiometric sensor was developed for the determination of Cr(III) ions in real solid samples. For this purpose, a new Schiff base (4-((E)-(2-amino-4 chlorophenylimino) methyl) -5-(hydroxymethyl)-2-methylpyridin-3-ol) were synthesized based on a chemical methods and utilized as a novel and sensitive ionophore for the preparation of Cr(III)-carbon paste electrode. Percentage of carbon paste electrode composition including, graphite powder, ionophore, paraffin oil as a binder, and graphene oxide(GO), was optimized with a chemometric approach using a central composite design method. The optimum percentage of ionophore and nanomaterial in the electrode was obtained 15%w/w. The predicted slope by the computational method and the obtained slope by the experimental method for the proposed sensor was not significantly different. The sensor was linear in the range of 1×10-10- 1×10-2 M for the determination of Cr(III).The effects of other parameters such as pH, response time, lifetime, and interfering ions were studied with one factor at the time method in the optimal composition of the sensor. Proper range of pH, lifetime and response time were acquired 3.5-9.0, 8 weeks and 10 s, respectively. The essential advantages of the proposed sensor were the suitable linear range, a wide range of pH, proper sensor stability, and fast response for the Cr(III) determination. Finally, the analytical application of prepared sensor evaluated to determine Cr(III) in waste and tap water samples.
Analytical chemistry
Ranjhan Junejo; Shahabuddin Memon; Ismail Murat Palabiyik
Abstract
Water might be contaminated by different metal ions, resulting in different water-borne diseases in human and aquatic life. This research study aimed at synthesizing the diethylamine functionalized calix[4]arene based silica (DFCS) resin for the effective removal of heavy metals such as Cd2+, Pb2+, and ...
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Water might be contaminated by different metal ions, resulting in different water-borne diseases in human and aquatic life. This research study aimed at synthesizing the diethylamine functionalized calix[4]arene based silica (DFCS) resin for the effective removal of heavy metals such as Cd2+, Pb2+, and Hg2+ from water. The DFCS resin was characterized using the FTIR spectroscopy and SEM techniques. The efficiency of the DFCS resin for the removal of metal ions was evaluated by performing equilibrium studies under the optimized conditions. Moreover, the experimental data were subjected to isotherm models; however, the Freundlich model was best-fit one as compared to the Langmuir model. The energy calculated from the D-R model was 10.3, 9.7 and 9.2 KJ/mol for Cd2+, Pb2+, and Hg2+,respectively, suggesting that the ion exchange process is involved. The thermodynamic values revealed that the reaction is spontaneous and exothermic, following the pseudo second-order kinetic model equation.
![Efficient adsorption of heavy metal ions onto diethylamine functionalized calix[4]arene based silica resin](data/ecc/coversheet/501587187473.png)
Analytical chemistry
Amin Amraei; Afshin Akbari Dehkharghani
Abstract
Aggregation of solid particles in the drilling fluid has adverse effects on the drilling performance, including blocking drilling pipe, reducing fluid lubrication, and the blowout action. The purpose of this study was to prepare a solution for breaking the adhesion forces between the suspended solids ...
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Aggregation of solid particles in the drilling fluid has adverse effects on the drilling performance, including blocking drilling pipe, reducing fluid lubrication, and the blowout action. The purpose of this study was to prepare a solution for breaking the adhesion forces between the suspended solids and drilling fluid molecules. To investigate the effect of the ultrasonic waves on the separation of solid particles from reversed emulsion fluid, in vitro studies were conducted. Drilling mud was prepared in the form of different samples and the samples were then irradiated with ultrasonic waves for 2, 5, and 10 min and the intensities of 50, 100, and 150 W/m2. To evaluate the stability of the emulsions and the efficiency of the separation process, caliper (volumetric) and density measurement methods were utilized. The results revealed increased time and intensity of the ultrasonic radiation separates the phases and fine particles from the emulsion, and also increased the stability of reversed emulsion. The increased radiation time and intensity did not have any effect on the drilling mud and only delayed the optimal operation time and energy consumption.
Analytical chemistry
Sareh Sadat Moshirian-Farahi; Hassan Ali Zamani; Mohamadreza Abedi
Abstract
A high sensitive electroanalytical-based sensor for determination of isoprenaline was fabricated by modification of carbon paste electrode (CPE) by NiO-Pt-Pd/CNTs composite as conductive mediator and n-hexyl-3-methylimidazolium hexafluoro phosphate (NHIHP) as conductive binder. The NHIHP/NiO-Pt-Pd/CNTs/CPE ...
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A high sensitive electroanalytical-based sensor for determination of isoprenaline was fabricated by modification of carbon paste electrode (CPE) by NiO-Pt-Pd/CNTs composite as conductive mediator and n-hexyl-3-methylimidazolium hexafluoro phosphate (NHIHP) as conductive binder. The NHIHP/NiO-Pt-Pd/CNTs/CPE was improved the oxidation signal of isoprenaline ⁓3.47 times and reduced oxidation over-potential of drug ⁓180 mV. The pH investigation confirmed that redox behavior of isoprenaline is depended of pH solution with equal value of electron and proton in redox mechanism. The NHIHP/NiO-Pt-Pd/CNTs/CPE was successfully used for determination of isoprenaline in the concertation range 0.003-300 µM with detection limit 0.9 nM by square wave voltammetric method. The standard addition results showed powerful ability of NHIHP/NiO-Pt-Pd/CNTs/CPE as an electroanalytical tool for determination of isoprenaline in the pharmaceutical and clinical samples with recovery data 98.76-105.06%.
Analytical chemistry
Mohammad Reza Aflatoonian; Somayeh Tajik; Behnaz Aflatoonian; Mehri-Saddat Ekrami-Kakhki; Reza Alizadeh
Abstract
Electrochemical behaviors of epinephrine and acetylcholine were investigated, using cyclic voltammetry, on the Ag-ZnO modified screen-printed electrode (Ag-ZnO/SPE). Ag-ZnO nanoplates showed excellent electrocatalytic activity toward the oxidation of epinephrine and acetylcholine compared with bare SPE ...
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Electrochemical behaviors of epinephrine and acetylcholine were investigated, using cyclic voltammetry, on the Ag-ZnO modified screen-printed electrode (Ag-ZnO/SPE). Ag-ZnO nanoplates showed excellent electrocatalytic activity toward the oxidation of epinephrine and acetylcholine compared with bare SPE in 0.1 M PBS. Under the optimized experimental conditions, a linear response obtained in the range of 0.13 to 450.00 μM with detection limit of 0.04 μM for epinephrine. Ag-ZnO/SPE exhibits good stability, reproducibility and repeatability, and the method has been successfully applied for detection of epinephrine and acetylcholine in their pharmaceutical and biological samples with satisfactory recovery.
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