Ashraf Salmanipour; Sara Hooshmand
Volume 1, Issue 1 , March 2014, , Pages 1-6
Abstract
In this work, an optical sensor for detection of ascorbic acid is described. The sensor is fabricated by casting and spin-coating silica sol-gel doped with 2,6-dichlorophenol indophenol on the glass plates. The sols are in turn obtained by acidic hydrolysis of various precursors such as tetraethoxysilane, ...
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In this work, an optical sensor for detection of ascorbic acid is described. The sensor is fabricated by casting and spin-coating silica sol-gel doped with 2,6-dichlorophenol indophenol on the glass plates. The sols are in turn obtained by acidic hydrolysis of various precursors such as tetraethoxysilane, triethoxymethylsilane and triethoxyoctylsilane in the presence of 2,6-dichlorophenol indophenol as dopant. Prepared sols then were coated on glass plates to form sol-gel films. UV-Vis spectrophotometric properties of 2,6-dichlorophenol indophenol doped in sol-gel films were studied and compared with in solution. At the optimum conditions the response of film to ascorbic acid is fast and linear in 0.07 – 3.34 mmol L-1 range. Detection limit and relative standard deviation of presented sensor for determination ascorbic acid were 0.05 mmol L-1 and 1.32 %, respectively.
Ashraf Salmanipour; Mohammad Ali Karimi; Alireza Mohadesi; Mohammad Ali Taher; Shabnam Shafiee
Volume 3, Issue 1 , March 2016, , Pages 1-26
Abstract
Considerable interest in the analysis of urea in clinical, environmental and industrial samples has generated diverse research activities in the fabrication of urea biosensors over the past decades. These activities have been directed towards the use of wide ranging materials, including conducting polymers, ...
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Considerable interest in the analysis of urea in clinical, environmental and industrial samples has generated diverse research activities in the fabrication of urea biosensors over the past decades. These activities have been directed towards the use of wide ranging materials, including conducting polymers, non-conducting polymers, redox dyes, redox polymers, oxides, clays, zeolite, sol gel, carbon pastes, epoxy activated support and nanomaterials, for the immobilisation of urease and its use for the detection of urea. Many of these activities have also employed various modes of transduction, including amperometric, potentiometric, conductometric, optical, manometric, thermal and piezoelectric detection, for reliable biosensing of urea. This article reviews the various research efforts that have been carried out over the past decades on the construction and utilisation of urea biosensors for urea analysis in various samples.
Soleiman Bahar
Volume 2, Issue 1 , March 2015, , Pages 1-6
Abstract
In this study, a sensitive method of dispersive liquid phase microextraction based on ion-pair combined with the flame atomic absorption spectrometry was proposed for the determination of trace Ni(II) using Aliquat 336-chloride as ion pair agent. Several factors which have effect on the microextraction ...
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In this study, a sensitive method of dispersive liquid phase microextraction based on ion-pair combined with the flame atomic absorption spectrometry was proposed for the determination of trace Ni(II) using Aliquat 336-chloride as ion pair agent. Several factors which have effect on the microextraction efficiency of Ni(II), such as pH, extraction and dispersive solvent type and their volume, concentration of the Aliquat 336-chloride, extraction time were investigated and the optimized experimental conditions were established. After extraction, the enrichment factor was 47. The detection limit of the method was 8.0 µg L-1 and the relative standard deviation for eight determinations of 100 µg L-1 Ni(II) was 2.1 %. The results for the determination of Ni(II) in food samples (black tea, lettuce, parsley and carrot) have demonstrated the accuracy, recovery and applicability of the proposed method.
Mohsen Nekoeinia; Saeed Yousefinejad; Mohammad Reza Abdi; Behnam Ebrahimpour
Volume 4, Issue 2 , September 2017, , Pages 1-9
Abstract
A simple and a green methodology has been developed for the preconcentration of Ni2+ based on the adsorption of its dimethylglyoximate complex on polydopamine coated Fe3O4 nanoparticles. The adsorbed complex was easily desorbed using 1.0 mL of CHCl3 and the concentration of nickel was determined by UV-Vis ...
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A simple and a green methodology has been developed for the preconcentration of Ni2+ based on the adsorption of its dimethylglyoximate complex on polydopamine coated Fe3O4 nanoparticles. The adsorbed complex was easily desorbed using 1.0 mL of CHCl3 and the concentration of nickel was determined by UV-Vis spectrophotometry. The effects of pH, sorbent mass, extraction time on the sorption of nickel dimethylglyoximate complex were investigated using Box–Behnken design. In optimal experimental conditions, a wide linear range of 5.0-600.0 μg/L with detection limit of 1.49 μg/L was obtained. The proposed method was applied for extraction and preconcentration of Ni2+ in various food samples and the results were compared with the official AOAC method.
Shahed Hassanpoor; Gholamreza Khayatian; Amin Zolali
Volume 4, Issue 1 , March 2017, , Pages 1-11
Abstract
A solid phase extraction method based on new functionalized silica gel sorbent for the preconcentration and determination of trace mercury (II) ions by cold vapor atomic absorption spectrometry (CV- AAS) was developed. The effective parameters on mercury extraction were optimized using two optimization ...
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A solid phase extraction method based on new functionalized silica gel sorbent for the preconcentration and determination of trace mercury (II) ions by cold vapor atomic absorption spectrometry (CV- AAS) was developed. The effective parameters on mercury extraction were optimized using two optimization methods: fractional factorial design and central composite design. Various factors affecting the recovery of the analyte were investigated using batch equilibrium technique. The best eluent for desorption of mercury was 5 mL of 0.1 M thiourea. Many anions and cations were examined in interference studies and the method shows very high selectivity for determination of mercury in presence of other species. Under the optimum conditions, the analytical curve was found to be linear in the range of 10- 1600 ng L-1 with a detection limit of 2.3 ng L-1. The method was successfully applied to determination of mercury in tap, river, sea water, urine and fish samples with good spike recoveries. The obtained results were in accordance with electrothermal atomic absorption spectrometric method. Student’s t-test indicated the validity and accuracy of the proposed method for analysis of mercury in real samples.
Sayed Zia Mohammadi; Maryam Balengei; Alieyeh Pourhasanghani; Samieh Fozooni; Asghar Amiri
Volume 5, Issue 1 , March 2018, , Pages 1-8
Abstract
A preconcentration procedure, based on the coprecipitation of Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions using a new organic coprecipitant, (2-(4-{[(4-{5-oxo-4-[1-(2-thienyl) methylidene]- 4,5-dihydro- 1,3- oxazole-2-yl} phenyl) imino] methyl} phenyl) methylidene ] amino} phenyl) -4-[ 1-phenyl methylidene] ...
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A preconcentration procedure, based on the coprecipitation of Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions using a new organic coprecipitant, (2-(4-{[(4-{5-oxo-4-[1-(2-thienyl) methylidene]- 4,5-dihydro- 1,3- oxazole-2-yl} phenyl) imino] methyl} phenyl) methylidene ] amino} phenyl) -4-[ 1-phenyl methylidene] -1,3-oxazole-5(4H)-one (OTMDO) without adding any carrier element has been developed. The resultant concentrated elements were determined by using flame atomic absorption spectrometer. The influences of some analytical parameters including pH, amount of the coprecipitant, standing time, centrifugation rate and time, sample volume and diverse ions were investigated on the quantitative recoveries of analyte ions. Under the optimized experimental conditions, the calibration curves for the analyte ions were studied. The relative standard deviations for seven replicate determinations of a mixture of 0.1 mg mL−1 Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions in the original solution were 2.5, 2.4, 2.2, 2.1 and 2.5%, respectively. The detection limits based on 3Sb/m for Mn2+, Co2+, Ni2+, Cd2+ and Cu2+ ions in the original solution were 1.2, 1.3, 1.2, 0.6 and 1.5 ng mL−1, respectively. The proposed method has been applied for determination of trace amounts of the analyte ions in the standard, water samples; brewed tea; tobacco samples and satisfactory results were obtained.
Hadi Farahani
Volume 5, Issue 2 , September 2018, , Pages 1-8
Abstract
A simple and efficient hollow fiber-based method, namely magnetic solvent bar liquid-phase microextraction (MSB-LPME) combined with gas chromatography-flame ionization detection (GC-FID) has been successfully developed for the sensitive determination of selected phthalate esters (PEs) in environmental ...
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A simple and efficient hollow fiber-based method, namely magnetic solvent bar liquid-phase microextraction (MSB-LPME) combined with gas chromatography-flame ionization detection (GC-FID) has been successfully developed for the sensitive determination of selected phthalate esters (PEs) in environmental water samples. The analytes were extracted from sample solution to the organic solvent immobilized in a fiber. Following the extraction, the analyte-adsorbed magnetic solvent bar can be easily isolated from the sample solution by a magnet which could greatly simplify the operation and also reduce the total pretreatment time. The bar was primarily eluted with methanol, evaporated to dryness while the residue was dissolved in toluene and finally injected into GC-FID. Begin with, effective parameters controlling the performance of the microextraction were evaluated and optimized. The values of the detection limit of the method were in the range of 0.02-0.09 µg L-1 and the RSD% values for the analysis of 25.0 g µL-1 of the analytes was below than 6.0% (n = 7). A worthy linearity (0.996 ≥ r2 ≥ 0.993) and a broad linear range (0.2-250 µg L-1) were achieved. The method was finally employed for the preconcentration and determination of the PEs in environmental water samples and satisfactory results were obtained.
Solomon Sime; Negussie Megersa; Abera Gure
Abstract
In this study, hollow-fiber based liquid-phase microextraction method was developed of for selective extraction and/or preconcentration of triazine herbicides (atratone, desmetryn and atrazine) from locally brewed Ethiopian beverages prior to their separation and quantitative determination by high performance ...
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In this study, hollow-fiber based liquid-phase microextraction method was developed of for selective extraction and/or preconcentration of triazine herbicides (atratone, desmetryn and atrazine) from locally brewed Ethiopian beverages prior to their separation and quantitative determination by high performance liquid chromatography with diode array detector. Parameters influencing extraction efficiency of the method including types of the extraction solvent, volume and pH of the sample solution, shaking speed, extraction time and salt concentration were investigated and optimum conditions were established. Under the optimal conditions limits of detections and quantifications were ranged from 0.02 – 0.04 and 0.05 – 0.12 µg/L, respectively. Calibration curves were linear over the range of 0.1 – 2 µg/L with coefficient of determinations of 0.990 or better. Intra- and inter-day precision studies, which were expressed as relative standard deviations were below 8 %. Satisfactory relative recoveries were also obtained for the target analytes, except for atrazine in Nech Tela and Filter Tela, which exhibited relatively lower recoveries. The results of the study indicated that the proposed method is an efficient alternative for selective extraction and/or preconcentration of residues of the target pesticides form Ethiopian locally brewed beverages as well as other similar sample matrices.
Alaa S. Amin; Ahmed Alharbi
Abstract
Ionic liquid based ultrasound-assisted dispersive liquid–liquid microextraction of trace levels of Rh3+ ions from aqueous samples is illustrated, to investigate a rapid and reliable sample pretreatment to determine Rh3+ ions spectrophotometrically. The Rh3+ is converted into its complex with 5-(4`-chlorophenylazo)-6-hydroxy-pyrimidine-2,4-dione ...
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Ionic liquid based ultrasound-assisted dispersive liquid–liquid microextraction of trace levels of Rh3+ ions from aqueous samples is illustrated, to investigate a rapid and reliable sample pretreatment to determine Rh3+ ions spectrophotometrically. The Rh3+ is converted into its complex with 5-(4`-chlorophenylazo)-6-hydroxy-pyrimidine-2,4-dione (CPAHPD) as a complexing agent, and an ultrasonic bath is used with the ionic liquid, 1-octyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide at room temperature is applied to extract the analyte. The centrifuged rhodium complex is enhanced in the form of ionic liquid droplets and prior to its spectrophotometric analysis, 250 µL ethanol is added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh3+ is examined and optimized. Under optimum conditions, the calibration graph is linear in the range of 10–260 ng mL−1, the detection limit is 3.2 ng mL−1 (3Sb/m, n=7) and the relative standard deviation is ± 1.78 % (n=7, C = 150 ng mL−1). Comparison with other procedures, the proposed procedure reduces the danger of exposure to toxic solvents, applied for extraction in conventional extraction procedures, it also requires a shorter extraction time. The method is successfully validated by the analysis of real samples and compared statistically with FG-AAS method. The proposed method is successfully validated by the analysis different complex materials such as environmental water and alloy samples and compared statistically with ETAAS method.
Ahmed Alharbi; Alaa S. Amin
Abstract
The use of a polymer inclusion membrane (PIM) as a sensing material is a novel approach to overcome the selectivity and stability of the optical chemical sensor (optode). In this work, non-plasticized PIM containing poly vinyl chloride (PVC) as a support base, 2-(2-benzothiazolylazo)phenol (BTAP) ...
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The use of a polymer inclusion membrane (PIM) as a sensing material is a novel approach to overcome the selectivity and stability of the optical chemical sensor (optode). In this work, non-plasticized PIM containing poly vinyl chloride (PVC) as a support base, 2-(2-benzothiazolylazo)phenol (BTAP) as a reagent and Aliquat 336 as a fixed carrier (ionophore) was prepared and its performance was tested for application in an optode to determine Fe3+ ions. The results showed that PIM properties are greatly affected by the membrane composition. The studies revealed that the optode response was dependent on film thickness, the presence of plasticizer, stirring effect, concentration of BTAP, concentration of Aliquat 336 and pH of the aqueous solution used. A linear calibration curve in the range from 5.0–210 ng mL−1 of Fe3+, with a detection and quantification limits of 1.60 and 4.95 ng mL−1, respectively were obtained. The maximum wavelength (λmax) for the PIM based optical optode was 581 nm. The PIM developed in this investigation was found to be stable, has good mechanical strength, sensitive and reusable. Lastly, the PIM was successfully applied as an optical sensor to determine Fe3+ ions in natural water, food, biological and environmental samples, and the obtained result is comparable to atomic absorption spectrometry method.
Mehdi Hosseini; Arman Naderi; Zeinab Fazli
Abstract
In the present research, the application of a functionalized ionic liquid with a specific role to simultaneous extraction and preconcentration of cadmium and lead ions in aqueous media by in-situ solvent formation microextraction (ISFME) technique was developed. The task-specific functionalized ionic ...
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In the present research, the application of a functionalized ionic liquid with a specific role to simultaneous extraction and preconcentration of cadmium and lead ions in aqueous media by in-situ solvent formation microextraction (ISFME) technique was developed. The task-specific functionalized ionic liquid of 3-(2-(bis(2-(tert-butoxy)-2-oxoethyl)amino)ethyl)-1-methylimidazolium chloride ([Tamim][Cl]) as a complexing agent utilized for the formation of metal chelates with Cd(II) and Pb(II) ions in aqueous solutions. Finally, determination of concentrated or separated metal ions contents after dilution step was carried out by flame atomic absorption spectrometry (FAAS). To obtain optimum extraction conditions, analytical parameters including the various range of sample solution pH, chelating agent amount, ionic strength of solution, solution temperature and counter ion dosage were investigated. Furthermore, parameters represent figures of merit of the method such as limit of detection (LOD), relative standard deviation (RSD), linear dynamic range (LDR) and the enhancement factor (EF) were 0.64;0.76 µg L-1, 1.5;1.8%, 50-2500;50-2000 µg L-1 and 85;80 for cadmium and lead, respectively. The ability of the method for analyzing of real water and saline samples were evaluated and good results were obtained.
Abdulfattah Mohammed Alkherraz; Mohammed Mustafa Sebsi; Mohamed Sassi; Khaled Muftah Elsherif
Abstract
The aim of this study was to estimate and compare some of chemical constituents in nuts and seeds consumed as snacks and available in the local market of Misurata city in Libya. 18 kinds of local and imported raw and roasted nuts and seeds samples were randomly collected from stores distributed across ...
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The aim of this study was to estimate and compare some of chemical constituents in nuts and seeds consumed as snacks and available in the local market of Misurata city in Libya. 18 kinds of local and imported raw and roasted nuts and seeds samples were randomly collected from stores distributed across the city, with 3 - 4 replicates of each kind, in order to estimate the concentrations of some chemical components and heavy elements, which were lead (Pb), cadmium (Cd), Iron (Fe), copper (Cu), chromium (Cr), manganese (Mn), cobalt (Co), zinc (Zn), nickel (Ni), moisture, ash, total solids and protein. The dry digestion method was used to prepare the samples for heavy metals determination using Flame Atomic Absorption Spectrometer. Also, moisture, ash and total solids contents were determined, and Kjeldahl method was used to estimate proteins. The results showed that the average concentrations of heavy metals varied significantly with sample kind. The levels of the studied metals were as follows: 0.075 - 1.167, 31.50 - 116.00, 0.325 - 1.325, 9.425- 71.00, 0.025-3.87, 8.325- 24.825, 0.175- 1.250, 0.050- 0.750, 43.00- 98.325 mg/kg, for Co, Zn, Ni, Mn, Pb, Cu, Cr, Cd, and Fe, respectively. Also, levels of moisture contents, ash contents, total solids contents, and protein levels were: 4.0 - 8.5%, 2.0 - 11.39%, 91.5 - 96.0%, and 11.8 - 33.2%, respectively. Most of the obtained results were consistent with the previous studies and within the permissible limits.
Esmat Koohsaryan; Mansoor Anbia; Mohammad Sepehrian
Abstract
In this study, hierarchical NaP zeolite was prepared for dehydration of a wet nitrogen gas stream using an adsorption system. Hierarchical NaP zeolite was synthesized via an easy hydrothermal process and characterized using several techniques such as scanning electron microscopy (SEM), X-ray diffraction ...
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In this study, hierarchical NaP zeolite was prepared for dehydration of a wet nitrogen gas stream using an adsorption system. Hierarchical NaP zeolite was synthesized via an easy hydrothermal process and characterized using several techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), BET surface area analysis and Fourier transform infrared (FT-IR) spectroscopy. An adsorption system comprising a desiccant packed column, humidity analyzer, and dry and wet gas cylinders was designed to evaluate the adsorption behavior of the synthesized NaP zeolite. Results indicated that hierarchical structure of NaP zeolite made a high surface area for water removal from a non-corrosive gas stream at ambient condition as it could reduce the water content of the gas from an initial concentration of 53 ppmv to approximately 5 ppmv after just one minute of the experiment.
Nayereh Rahimian; Javad Feizy; Zarrin Eshaghi
Abstract
In recent years, the presence of bisphenol A in food, drinking water, and toys is considered as a toxic compound. In this research, a Fabric-phase sorptive extraction using an organic-inorganic coating as an adsorbent was used to separate bisphenol A in different samples. The isolated bisphenol A was ...
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In recent years, the presence of bisphenol A in food, drinking water, and toys is considered as a toxic compound. In this research, a Fabric-phase sorptive extraction using an organic-inorganic coating as an adsorbent was used to separate bisphenol A in different samples. The isolated bisphenol A was measured by high-performance liquid chromatography. The organic-inorganic coating was done with other methods. Optimal conditions for selecting the type of fabric and bis phenol A extraction were obtained by the central composite design in 3 and 5 variables according to the response surface methodology. At first, the influencing factors in NFPSE such as fabric type, number of sol-gel connections, and binding time were investigated. Also, the effects of different parameters on adsorption such as sample volume, adsorption time, solution desorption volume, desorption time and pH were examined. The calibration curve in the region (0.1-15 ng.mL-1) for bisphenol A was linear with a correlation coefficient of more than 99%.The detection limit (LODs)andthe limit of quantificationwere 0.11 ng.mL-1 and 0.37 ng.mL-1 respectively.Repeatability (RSD) with three replicated experiments was 1.25%.The recovery was obtained for different samples in the range of 95 to 97 %. According to the obtained results, the method mentioned in this research can be introduced as a reproducible method with a high absorption capacity for bisphenol A determination in drinking water and toys.
Soleyman Bahar
Volume 2, Issue 2 , September 2015, , Pages 63-69
Abstract
In this work, a procedure for preconcentration of silver using dispersive liquid–liquid microextraction with the reagent dithizone as complexing reagent was developed. At pH 2, silver ions are complexed with dithizone and extracted into the fine droplets formed when mixing carbon tetrachloride ...
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In this work, a procedure for preconcentration of silver using dispersive liquid–liquid microextraction with the reagent dithizone as complexing reagent was developed. At pH 2, silver ions are complexed with dithizone and extracted into the fine droplets formed when mixing carbon tetrachloride (extraction solvent), ethanol (disperser solvent) and the sample solution. After extraction, the phases are separated by centrifugation and silver is determined in the enriched phase by FAAS. After extraction, the enrichment factor was 73.21. The detection limit of the method was 30.4 ng mL-1 and the relative standard deviation for ten determinations of 0.1 µg mL-1 silver was 3.19 %. The results for the determination of silver in environmental water samples (tap water, well water, mineral water), tea and pepperbrush have demonstrated the applicability of the proposed method.
Hossein Tavallali; Gohar Deilamy-Rad; Abolfath Parhami; Sajedeh Lohrasbi
Volume 3, Issue 2 , September 2016, , Pages 76-87
Abstract
A new diazo based, Congo-Red-Cu , was developed to act as an ‘Off–On’ reversible fluorescent probe for CN− detection. The changes in solvent composition has been shown greatly effective on selectivity of anion sensing through eliminate of sulfite interference. Increasing the amount ...
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A new diazo based, Congo-Red-Cu , was developed to act as an ‘Off–On’ reversible fluorescent probe for CN− detection. The changes in solvent composition has been shown greatly effective on selectivity of anion sensing through eliminate of sulfite interference. Increasing the amount of ethanol up to 5% (v/v) cause a dramatic development in selectivity of CN−via inhibitory effect on sulfite interferent. The chemosensing behavior of the CR-Cu has been demonstrated through fluorescence, absorption, visual color changes and FT-IR studies. This chemosensor (CR-Cu) has been shown a significant visible color change and displays a remarkable fluorescent switch on in the presence of CN− ions. The ‘in situ’ prepared CN− complexes of CR-Cu shows high “Turn-Off” selectivity toward CO32− over the other anions. The detection limits for CN− were 90 and 20 nM for colorimetric and fluorometric methods respectively, that is far lower than the WHO guideline of 1.9 µM. The complex of CN− with CR-Cu also displayed ability to detect up to 15 nM CO32− among other competing anions through a fast response time of less than 30 s which is much lower than most recently reported chemosensor probes. It has been possible to build an INHIBIT logic gate for two binary inputs viz., CN− and CO32− by monitoring the fluorescence emission band at 446 nm as output. The development of fluorometric an ‘‘Off–On’’ reversible switch for three chemical inputs Cu2+, CN− and CO32− ions and mimics a molecular level keypad lock.
Mohammad Ali Karimi; Abdolhamid Hatefi-Mehrjardi; Alireza Mohadesi; Sayed Zia Mohammadi; Mehdi Taghdiri; Javad Yarahmadi; Havva Mahmoodian; Shahla Nezhad Khorasani
Volume 1, Issue 1 , March 2014, , Pages 7-11
Abstract
In this work, a new, simple and fast method for the solid phase extraction-spectrophotometric determination of phosphate using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs) has been developed. The determination of phosphate is based on the molybdenum ...
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In this work, a new, simple and fast method for the solid phase extraction-spectrophotometric determination of phosphate using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs) has been developed. The determination of phosphate is based on the molybdenum blue method which was monitored at λmax of 810 nm. MNPs and ACMNPs characterized by SEM, VSM, and XRD spectroscopy. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. Under the optimal experimental conditions, the preconcentration factor (PF), detection limit (DL), linear range (LR) and relative standard deviation (RSD) of phosphate were 80 (for 400 mL of sample solution), 0.038 µg mL−1, 0.8-10.0 µg mL−1 and 2.5 % (for 5.0 µg mL-1, n=7), respectively. The proposed method was successfully applied to the separation/preconcentration and determination of phosphate in different water samples and suitable recoveries were obtained.
Fatemeh Sabermahani; Tayebeh Paykani; Samieh Fozooni
Volume 2, Issue 1 , March 2015, , Pages 7-13
Abstract
In the present work, a new kind of alumina-based adsorbent with high selectivity and stability and efficient adsorption was prepared. Alumina was coated with an oxazolone azo dye, 2-(4-{2-[4-(dimethylamino) phenyl]-1-diazenyl}phenyl)-4-[1-phenyl methylidene]-5(4H)-oxazolone, and then used for preconcentration ...
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In the present work, a new kind of alumina-based adsorbent with high selectivity and stability and efficient adsorption was prepared. Alumina was coated with an oxazolone azo dye, 2-(4-{2-[4-(dimethylamino) phenyl]-1-diazenyl}phenyl)-4-[1-phenyl methylidene]-5(4H)-oxazolone, and then used for preconcentration of trace amounts of palladium. The analytical procedure involved the complex formation of Pd with oxazolone azo dye as a chelating agent in buffer media of pH 5. The stability of sorbent was excellent and adsorption capacity did not change significantly after 100 consecutive uses of 50.0 mg of modified alumina. Under the optimum conditions, the preconcentration factor of the method was 150. The linearity was maintained in the concentration range of 0.33 ng mL-1 to 8.0 mg mL-1 in the original solution. For 2.0 µg mL-1 of Pd, the relative standard deviation 1.4% and detection limit 0.25 ng mL-1 was obtained. The proposed method was successfully applied to the determination of trace amounts of palladium in the anodic slime and wastewater samples.
Arezoo Zohourtalab; Habib Razmi
Volume 5, Issue 1 , March 2018, , Pages 9-16
Abstract
A kind of ferrocene mediated enzymatic biosensor was fabricated in order to the measurement of glucose as an important biological analyte. A homogenous mixture of ferrocene including Chitosan(CS), Nafion(Nf) and an imidazolium based ionic liquid, 1-butyl-3-methyl imidazoliumhexafluorophosphate, ...
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A kind of ferrocene mediated enzymatic biosensor was fabricated in order to the measurement of glucose as an important biological analyte. A homogenous mixture of ferrocene including Chitosan(CS), Nafion(Nf) and an imidazolium based ionic liquid, 1-butyl-3-methyl imidazoliumhexafluorophosphate, [BMIM]HF6PO4, was prepared. The mentioned mixture was cast on the surface of carbon ceramic electrode and an enzymatic layer was entrapped between two layers of this mixture in order to improving the mechanical stability of the biosensor. Cyclic voltammetry and chronoamperometry were used to investigate the analytical performance of the biosensor. Remarkable deduction of interfering signals produced by AA and UA was obtained by applying a constant potential (180mV) on the human plasma for a short period of time (100min). Values of practical parameters such as sensitivity (2.73 µA mM-1cm-2), linear range (95.23–1367.5 µM) and detection limit (48 µM) were obtained by the chronoamperometric studies. The apparent Michaels-Menten constant, Km (3.52 mM) was also calculated. In order to estimate the practical accuracy and precision of the enzymatic biosensor, a test of spiked glucose solution recovery in natural plasma was done.
Fatemeh Moeinpour; Zarrin Eshaghi
Volume 5, Issue 2 , September 2018, , Pages 9-16
Abstract
The aim of this work was indirect determination of anti-cancer drug capecitabine using complexation with platinum (IV) and determination by graphite furnace atomic absorption spectroscopy (GFAAS). For this aim at first, the complex of platinum with capecitabine was performed and the ratio of drug to ...
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The aim of this work was indirect determination of anti-cancer drug capecitabine using complexation with platinum (IV) and determination by graphite furnace atomic absorption spectroscopy (GFAAS). For this aim at first, the complex of platinum with capecitabine was performed and the ratio of drug to metal was evalutsd with several ways. In the all of these methods, the ligand to metal ratio of the Potassium hexachloroplatinate (IV) and capecitabine complex was found to be 2:1. The extraction process was carried out by the hollow fiber supported functionalized multiwalled carbon nanotubes/ polyurethane foam (fMWCNT/PUF) foam as the solid adsorbent in the solid phase microextraction mode. The amount of desorbed platinum ion has been indirectly used to measure the drug concentrations. Parameters affecting the hollow fiber-solid phase microextraction (HF-SPME) such as pH of the donor phase, donor phase volume, the sorbent type and desorption solvent were optimized. Calibration graph was plotted and a curve with a linear response range of the 3.32 to 98.17 µg mL -1 and a detection limit 0.38 µg mL -1 was obtained.
Reza Samimi; Reza Mortazavi; Simin Mansouri; Zohre Fathi; Foroozan Hasanpour
Abstract
Computational and experimental approach on standard redox potential of dobutamine was developed in aqueous media. A direct and indirect calibrated B3LYP/6-311++G (d, p) method predicted the aqueous phase redox potential of dobutamine as 0.850 V Respectively. The electronic densities of dobutamine calculation ...
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Computational and experimental approach on standard redox potential of dobutamine was developed in aqueous media. A direct and indirect calibrated B3LYP/6-311++G (d, p) method predicted the aqueous phase redox potential of dobutamine as 0.850 V Respectively. The electronic densities of dobutamine calculation at oxidation and reduction state in HOMO and LUMO proved that energies of dobutamine LUMO in oxidation form are lower than dobutamine LUMO in reduction. Therefore, the electron transfer from HOMO to LUMO in dobutamine oxidation form is easier than in dobutamine reduction form. The experimental E° was obtained using cyclic voltammetry at activated glassy carbon electrode as 0.79V versus SHE. The results show that there is a satisfactory agreement between the experimental and computational standard potential value of dobutamine.
Mohammad Reza Rezaei Kahkha; Massoud Kaykhaii; Mahdi Shafee-Afarani; Batool Rezaei Kahkha
Volume 4, Issue 2 , September 2017, , Pages 10-16
Abstract
In this work, a microextraction technique based on pipette tip solid-phase extraction was used for preconcentration and determination of diazinon. Carbon nanotube functionalized by zinc sulfide and ethylene glycol was used as sorbent. Determination of diazinon was performed using high performance liquid ...
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In this work, a microextraction technique based on pipette tip solid-phase extraction was used for preconcentration and determination of diazinon. Carbon nanotube functionalized by zinc sulfide and ethylene glycol was used as sorbent. Determination of diazinon was performed using high performance liquid chromatography and UV detection. Important parameters that influence the extraction efficiency (i.e. pH, amount of adsorbent, extraction time, salt addition, volumes of sample and eluting solvent and number of aspirating/dispensing cycles for both solvent and sample) were investigated and optimized. Results were showed that method was validated over the range of 0.50 - 100.0 µg L-1. Repeatability was satisfactory, bellow 3.78% for 5 replicate measurements of 20 µg L-1 of diazinon. The limit of detection of this method is 0.03 µg L-1 with an enrichment factor of 100 and short extraction time of 8.5 min, which confirmed suggested method is a reliable and accurate for extraction and preconcentration of diazinon.
Ahmadreza Amraei; Ali Niazi; Mohammad Alimoradi; Mohammad Hosseini
Abstract
A rapid, powerful, satisfactory and modified signal-pre-processing method that is a hybrid of the wavelet transform with orthogonal signal correction (OSC) is used for pre-processing of spectrophotometric data of naphthalene, anthracene and pyrene as analytes after their preconcentration by salting-out ...
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A rapid, powerful, satisfactory and modified signal-pre-processing method that is a hybrid of the wavelet transform with orthogonal signal correction (OSC) is used for pre-processing of spectrophotometric data of naphthalene, anthracene and pyrene as analytes after their preconcentration by salting-out assisted liquid–liquid extraction (SALLE) method. Water-miscible extraction solvent (1.0 mL of acetonitrile) and a suitable amount of salt (1.0 g of (NH4)2SO4) are added into the aqueous solution (4.0 mL) and dissolved using a vortex leading to the occurrence of phase separation. The target analytes in the sample was extracted into the water-miscible extraction solvent. After extraction, the absorbance of the analytes mixture was measured in the wavelength range of 200-400 nm. The wavelet orthogonal signal correction (WOSC) was established for denoising and reduction of spectrophotometric data and hybrid with partial least squares (PLS) regression method for simultaneous determination of the studied analytes after the SALLE procedure. The influence of various parameters, such as extraction solvent and volume, type and amount of salt, vortex time and sample pH were studied and optimized. The net analyte signal (NAS) method was used for calculating figures of merit. Linear range (LR) of calibration graphs for naphthalene, anthracene and pyrene were between 0.20 - 2.00, 0.10 - 1.50 and 0.07 -1.00 µg mL-1, respectively. The obtained model showed good prediction capability with root mean square error of prediction (RMSEP) of 0.030, 0.024 and 0.013 µg mL-1 for naphthalene, anthracene and pyrene, respectively. The simple WOSC-PLS method has been successfully applied for the simultaneous determination of these analytes in the spiked wastewater samples.
Homa Shafieekhani; Somayeh Karimi; Mohammad Torkashvand
Abstract
A new organic compound, namely dihydropyrimido [4,5-b][1,6] naphthyridine-2,4, 6, 8(1H,3H,7H,9H)-tetraones with amino acid moiety (DHPN) was synthesized and characterized by 1H, 13C Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy experiments. DHPN was investigated ...
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A new organic compound, namely dihydropyrimido [4,5-b][1,6] naphthyridine-2,4, 6, 8(1H,3H,7H,9H)-tetraones with amino acid moiety (DHPN) was synthesized and characterized by 1H, 13C Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy experiments. DHPN was investigated for the first time as a green inhibitor of mild steel (A105) corrosion in acidic (0.1, 0.5 mol L-1 H2SO4 and HCl) solutions using potentiodynamic polarization technique. The results showed that, inhibition efficiency increased with the inhibitor concentration within the range of 0.95-19 mg L-1. The polarization curves demonstrated that, this compound act as a mixed type inhibitor. The adsorption of the DHPN molecule on the surface of mild steel was found to obey the Langmuir adsorption isotherm. Besides, data processing methods like support vector machine modelling was performed to prove the relationship between inhibitory effect and molecular structure.
Mahmood Payehghadr; Homa Shafieekhani; Ali Morsali
Volume 4, Issue 1 , March 2017, , Pages 12-17
Abstract
A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene)({2-(E)-(Pyridine-2-ylmethylidene)amino]ethyl}has been synthesized and kf value of its complexes with Cu2+, Ni2+, Cd2+, Zn2+, Hg2+ and Co2+has been determined by spectrophotometric and conductometric methods in acetonitrile at various temperatures. ...
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A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene)({2-(E)-(Pyridine-2-ylmethylidene)amino]ethyl}has been synthesized and kf value of its complexes with Cu2+, Ni2+, Cd2+, Zn2+, Hg2+ and Co2+has been determined by spectrophotometric and conductometric methods in acetonitrile at various temperatures. The formation constants (Kß = K1 × K2) of the 1:1 and 1:2 (metal ion to ligand) complexes were calculated by computer fitting of the absorbance-mole ratio data, and molar conductance-mole ratio data at different temperatures, and found that complexes to vary in acetonitrile solvent in the order of Cu2+ >Hg2+>Zn2+>Co2+> Cd2+> Ni2+>Ag+. The enthalpy and entropy changes of the complexation reaction were evaluated from the temperature dependence of formation constants.