فهرست مطالب

  • Volume:6 Issue: 1, 2019
  • تاریخ انتشار: 1397/12/07
  • تعداد عناوین: 18
  • Raziyeh Fayazi , Masoud Ghanei, Motlagh Pages 1-12
    In the present study, a simple electrochemical sensor for trace determination of Hg(II) ions in aqueous solutions was introduced. The proposed sensor was designed by incorporation of the 4-methyl-piperidine-carbodithioate capped gold nanoparticles (GNPs) into the carbon paste electrode (CPE), which provides a remarkably improved sensitivity for stripping voltammetric determination of Hg(II). Differential pulse voltammetry (DPV) was applied for quantitative determinations. The resulting electrode exhibited a linear relationship towards Hg(II) concentrations ranging from 0.4 to 100.0 μg L-1. The detction limit was found to be 0.2 μg L-1 (S/N = 3) that is lower than the permitted value of Hg(II) reported by the Environmental Protection Agency (EPA) limit for drinkable water. The relative standard deviation (RSD) for 7 successive measurements at different electrodes was also found to be 3.8%. The interference studies showed that the several common metal ions did not interfere with the quantitative mercury determination. The designed sensor was further utilized for the determination of mercury ions in real water samples with satisfactory results.
    Keywords: heavy metals, Gold Nanoparticles, Mercury(II), Voltammetry, Carbon paste electrode
  • Mahmoud Roushani , Faezeh Shahdost, fard Pages 13-27
    A selective aptasensor was developed using the electrochemical transduction method for the ultrasensitive detection of cocaine. In this method, dendrimer-quantum dot (Den-QD) bioconjugate was utilized as a specific nanocomposite to efficiently fabricate the aptasensor. CdTe QD, which carries highly significant properties, was immobilized on the surface of a glassy carbon electrode (GCE), and polyamidoamine (PAMAM) dendrimer (Den) was covalently attached to the carboxyl-terminated surface of the CdTe QDs. This clever combination of QD and Den provides a highly stable matrix for the increased loading of aptamer (Apt) as a cocaine molecular receptor via covalent attachment. The Apt was functionalized with AuNPs leading to the amplification of the electrochemical signal. In this study, upon the incubation of cocaine on the aptasensor surface, the peak current of the redox probe decreased due to the hindered electron transfer reaction on the sensing surface. It has shown that the proposed aptasensor can detect cocaine by electrochemical impedance spectroscopy (EIS) technique at a linear range (5.00  10-3-6.00 nM) and a capability of detection down to 1.60 pM. The excellent specificity of this sensing system is demonstrated by using some common analgesic drugs, and finally, the proposed aptasensor was successfully used to measure cocaine in the human serum sample. The proposed methodology may hold great promise for the design of other aptasensors and immunosensors based on the use of the Den-QD bioconjugate as a nanocomposite with high performance.
    Keywords: Aptasensor, Dendrimer, Quantum dot, Bioconjugate, Cocaine
  • Mir Ali Farajzadeh , Masoumeh Sattari Dabbagh, Adeleh Yadegari, Ali Akbar Alizadeh Nabil Pages 29-46
    Two convenient sample preparation methods, air–assisted liquid–liquid microextraction (AALLME) and dispersive liquid–liquid microextraction (DLLME) have been developed for the simultaneous determination of multiclass pesticide residues in vegetable and fruit juice samples with gas chromatography–flame ionization detection and the advantages of each method were investigated. In AALLME, fine droplets of an extraction solvent were immediately formed by suction with a syringe and injection of the mixture of an aqueous sample solution and an extraction solvent into a test tube for several times. In DLLME, the cloudy solution was formed with the aid of a disperser solvent. The effect of main factors, such as type and volume of extraction solvent, salt addition, pH, etc was studied. Under the optimum conditions, enrichment factors and extraction recoveries were obtained in the ranges of 262–515, 52–103% and 45–438, 9.2–88% in AALLME and DLLME methods, respectively. Both methods are inexpensive, simple, fast, efficient, reliable, and sensitive. Therefore, the proposed methods are suitable for determination of trace levels of multiclass pesticide residues in fruit juice and vegetable samples.
    Keywords: Air-assisted liquid-liquid microextraction, Dispersive liquid-liquid microextraction, Fruit, vegetable samples, Gas chromatography, Multiclass pesticides
  • Naser Samadi , Saeedeh Narimani Pages 47-57
    In this research work,We have developed water soluble CdS quantum dot probes for detecting meropenem by using safe and low cost materials. This citrate capped CdS QDs are highly stable in aqueous solution and applied for selective and ultrasensitive Meropenem (MPN) sensing. The fluorescence intensities of CdS QDs were decreased linearly with increasing MPN in the wide range of 6×10−10 mol L−1 to 2.1×10−3 mol L−1. The limit of detection for meropenem determination was 0.5 nM. There was no significant wavelength shift on the fluorescence-quenched signals in the presence of the drug. The effect of common foreign ions and drugs on the fluorescence of the QDs was studied to evaluate the selectivity and the results showed a high selectivity of the Cit capped CdS QDs towards MPN. The validity of this method confirmed by high performance chromatography method (HPLC). The method presented here is simple, rapid, low cost, sensitive, inexpensive and suitable for practical applications.
    Keywords: CdS quantum dots, Fluorescence probe, Drug, Meropenem
  • Mohammad Amayreh , Mohammed Hourani Pages 59-68
    A direct method for hemoglobin determination in blood was developed using iodine-coated platinum electrode. The electrochemical behavior of iron ions in hemoglobin within human red blood cells was investigated by cyclic voltammetry at iodine-coated platinum electrode. A well-defined peak assigned to oxidation of hemoglobin was observed at about 0.4 V. A more prominent peak for the oxidation of hemoglobin wasobserved at pH 5.5 in 0.9% NaCl solutioncompared to phosphate puffer solution of pH 3.5.Using hydroxylamine in the dry form with the hemoglobin in red blood cells, enhanced thepeak current for hemoglobin oxidation by 14 folds. A linear relationship between the hemoglobin oxidation peak current and the concentration of hemoglobin was illustrated within the concentration range from1.53g/dl to 9.2g/dl with a correlation coefficient(R2=0.9949). The estimated detection limit based on S/N = 3 ratio was 0.004 g/dl. The developed method was directly applied to determination of hemoglobin without pretreatment of the blood sample. The developed method passed the tests for its liability towards interferences. The developed method was validated against the regular clinical analysis for hemoglobin. Analysis of real samples by the two methods indicated the absence of systematic errors as indicated by the confidence limits at 95% confidence level. Moreover, application of the null hypothesis to the results of the two methods indicated the validity of the null hypothesis(i.e., there is no significant difference between the two methods at p=0.05).
    Keywords: Hemoglobin analysis, Blood analysis, Iodine-coated platinum electrode, Cyclic Voltammetry
  • Fariba Garkani , Hadi Beitollahi, Somayeh Tajik, Shohreh Jahani Pages 69-79
    In this study, we combined the advantages of good conductivity, small size, and large surface area and the catalytic property of La3+/Co3O4 nanoflowers to fabricate an electrochemical sensor sensitive to determination of vitamin B6 in real samples. La3+/Co3O4 nanoflowers were synthesized by a co-precipitation method which is a convenient, environment-friendly, inexpensive process. The synthesized nanoflowers were characterized by SEM. A simple and sensitive sensor based on graphite screen printed electrode (GSPE) modified by La3+/Co3O4 nanoflowers was developed for the electrochemical determination of vitamin B6. The electrochemical behavior of vitamin B6 was studied in 0.1 M phosphate buffer solution (PBS) using cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV). The modified electrode (La3+/Co3O4NFs/GSPE) showed excellent electrocatalytic activity and remarkable sensitivity towards the oxidation of vitamin B6. The fabricated sensor displayed good operating characteristics including low detection limit, and a wide linear dynamic range for the detection of vitamin B6. Using La3+/Co3O4NFs/GSPE as the working electrode, a linear dynamic range between 1.0 to 600.0 μM and a limit of detection of 0.4 µM were obtained. Finally, reliability and accuracy of the proposed sensor were studied in real samples.
    Keywords: La3+, Co3O4 Nanoflowers, Electrochemical sensor, Vitamin B6, Real samples, Modified electrode
  • Hadi Beitollahi , Mohadeseh Safaei, Somayeh Tajik Pages 81-96
    Dopamine (DA) is one of the most important catecholamine neurotransmitters in the human central nervous system in the brain and plays a key role in the functioning of the renal, hormonal, and cardiovascular systems. Abnormal levels of dopamine are related to neurological disorders, such as schizophrenia and Parkinson’s disease and the control and fluctuations of the amount of dopamine are extremely important in monitoring with analytical systems in the human brain. This review covers the different electrochemical sensors for the determination of dopamine as neurotransmitter and points out the advantages and disadvantages of them. The interaction between the functional groups of the sensor’s material and the analyte molecule is discussed, as it is essential for the analytical characteristics obtained. The analytical performances of the voltammetric or amperometric chemical and biochemical sensors (linear range of analytical response, sensitivity etc) are highlightened. The numerous applications of DA electrochemical sensors in fields like pharmaceutical or clinical analysis, where DA represents a key analyte, are also presented.
    Keywords: Dopamine, Modified electrodes, Electrochemical detection, Neurotransmitters
  • Shaza AlShaal , Francois Karabet, Manal Daghestani Pages 97-110
    The phenolics of Syrian olive leaves were determined in alcoholic and aqueous extracts by the ultrasonic bath. Both of the total phenolic and flavonoids contents were compared, and the IC50 values were calculated for the inhibition of both of the free radical 2,2-diphenyl-1 picrylhydrazyl (DPPH.), the free monocation radical 2.2,-azino-bis-[3-ethyl benzothiazoline - 6 - Sulfonic Acid] (ABTS+.), for olive leaves extracts, and compared with vitamin C and oleuropein standard values. Oleuropein content was quantified in extracts using high -performance liquid chromatography (HPLC), and isolated by TLC, then it was detected by HPLC- MS. The results showed that the total phenolic content and total flavonoids content for alcoholic extracts were higher than in aqueous extract contents, with significant differences in the statistical study. There were no significant differences in their ability to inhibit (DPPH.), as opposed to the result with the monocation radical (ABTS+.), where the inhibitory capacity of the ethanolic extract was greater than in the aqueous one. The study also showed that the alcoholic extract contained a higher concentration of oleuropein (88.50±9.67 mg/g) comparing with the aqueous extract (37.60±6.84 mg/g), allowing the use of Syrian olive leaves extracts as natural antioxidants. The isolated oleuropein yield by TLC was (0.43-0.1) mg/g in both of ethanolic and aqueous extracts, respectively.
    Keywords: Total phenols, Total flavonoids, Antioxidant activity, IC50, Oleuropein
  • Shiva Ahmadi *, Ahmad Mani, Varnosfaderani, Buick Habibi Pages 111-124
    Nutritional value and quality features of oils are the most important factors that should be considered in food industry. There is no pure edible oil with appropriate oxidative stability and nutritional properties. Therefore, vegetable oils are blended to improve their applications and to enhance their nutritional quality. Characterization of edible oils is important for quality control and identification of oil adulteration. In this work, we propose a simple, rapid, inexpensive and non-destructive approach for characterization of different types of vegetable oil blends according to the corresponding color histograms. Regression models were applied on four datasets of binary edible oil blends including; Palm Olein-Rapeseed, Palm Olein-Sunflower, Soybean-Sunflower and Soybean-Rapeseed. In all of the aforementioned data sets, despite the high performances of Support Vector Regression (SVR) and Levenberg-Marquardt Artificial Neural Network (LMANN) regression models in terms of coefficient of determination, Bayesian Regularized Artificial Neural Networks (BRANN) provided better results up to 97% for HSI color histograms in both the training and test sets. In order to reduce the numbers of independent variables for modelling, principle component analysis (PCA) algorithm was used. Finally, the results of image analysis were compared with those obtained by processing of FT-IR spectra of mixtures of edible oils. The results revealed that image analysis of mixtures of edible oils yield comparable results to those obtained by processing of FT-IR spectra for characterization of edible oils. Our results suggest that the proposed method is promising for characterization of different binary blends of edible oils.
    Keywords: Multivariate calibration, Edible oil analysis, Image histograms, Artificial neural networks, Bayesian regularization
  • Maryam Fayazi * Pages 125-136
    The sepiolite-iron oxide nanocomposite (Sepiolite-Fe3O4) was synthesized via facile hydrothermal method and used as an efficient magnetic adsorbent for removal of Pb(II) ions from water samples. The Sepiolite-Fe3O4 nanocomposite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibration sample magnetometer (VSM) and scanning electron microscopy (SEM) techniques. The equilibrium data were tested using different isotherm models including Langmuir, Freundlich and Temkin. The adsorption isotherm fits well with the Langmuir model and the maximum Pb(II)-sorption capacity of 96.15 mg g-1 was calculated at room temperature. Kinetic data well interpreted with the pseudo-second-order model (R2 > 0.9998), that illustrated the adsorption process was controlled by chemical reactions. The as-prepared magnetic adsorbent was easily reused through sequential adsorption-desorption cycles, presenting that the Sepiolite-Fe3O4 nanocomposite has an acceptable stability and reusability. As a result, this study indicates that the novel adsorbent nanocomposite may be an ideal adsorbent for heavy metal-contaminated water treatment.
    Keywords: Lead removal, Sepiolite, Magnetic nanocomposite, Adsorption, Heavy metals
  • Setareh Gorji, Morteza Bahram *, Pourya Biparva Pages 137-156
    The current study describes a simple method to monitor bisphenol A (BPA) quantitatively through stir bar sorptive extraction (SBSE) coupled with high-performance liquid chromatography-ultraviolet (HPLC-UV) spectroscopy. The analyte was concentrated by SBSE based on self-magnetic nanocomposite monolithic (SMNM) kit. An experimental design based on the central composite design (CCD) was used to optimize factors affecting SBSE extraction. Limit of detection (LOD) of the BPA was 0.02 µg L-1 and 0.38 µg L-1 for bottled mineral water and bottled milk samples, whereas relative standard deviations (RSDs%) did not exceed 8.49% and 10.21 % for interday and intraday precisions, respectively. Interday and intraday precisions (n=3) were obtained by extracting BPA at the concentration level of 0.10 µg L-1 for bottled mineral water and 0.50 µg L-1 for bottled milk sample. The calibration curve of BPA showed good linearity for bottled mineral water and bottled milk samples such that the coefficients of determination (R2) were obtained to be 0.9976 and 0.9960, respectively. The proposed method was effectively used to analyze BPA in bottled mineral water and bottled milk samples.
    Keywords: Stir bar sorptive extraction, Self-magnetic nanocomposite monolithic kit, HPLC, Bisphenol A
  • Mahdi Ghamsari, Tayyebeh Madrakian* Pages 157-169
    In this study, the potentiality of Sulfonated-Oxidized activated carbon as an adsorbent for removing Methylene Blue (MB), Crystal Violet (CV), and Thionin Acetate (Th) from aqueous solutions was investigated. The characteristics of the synthesized adsorbent were examined by FTIR and SEM techniques. By changing experimental conditions like contact time and adsorbent dosage, initial pH was studied to find the optimum adsorption conditions. The results showed that the adsorption process is too fast and after about 1 minute more than 95% of dyes (20 mg L-1) were completely removed. The experimental data were well represented by Freundlich adsorption isotherm and the maximum adsorption capacities of MB, CV, Th dyes were calculated about 410.0, 405.5, 395.4 mg g-1 respectively. These findings are considerably higher than the adsorption capacities of reported adsorbent in the literature. In addition, simultaneous removal of the reported dyes was also carried out and more than 98% removal efficiency was obtained, therefore Sulfonated-oxidized activated carbon appears as an economical and effectual adsorbent for removal of MB, CV, Th from industrial waste waters.
    Keywords: Wastewater treatment, Dye removal, Activated carbon, Cationic dye, Sulfonation-oxidation
  • Somayeh Tajik, Hadi Beitollahi* Pages 171-182
    A glassy carbon electrode modified with graphene oxide (GO/GCE) is proposed as a novel electrochemical platform for detection of chlorpromazine. The electrochemical activity of GO/GCE towards chlorpromazine was investigated using cyclic voltammetry (CV) experiments in 0.1 M phosphate buffer solution (PBS). The overpotential for the oxidation of chlorpromazine decreased significantly and its oxidation peak currents increased dramatically at GO/GCE. The potential utility of the sensor was demonstrated by applying it to the analytical determination of chlorpromazine concentration using differential pulse voltammetry (DPV). These results are beneficial for real sample analysis. The sensor worked linearly in the range of 0.05 to 200.0 μM and had a detection limit of 42.0 nM using DPV. The fabricated sensor was successfully applied to the detection of chlorpromazine in real samples. The experiments illustrate that graphene oxide is a worthy electrode material which offers a large surface-to-volume ratio and improves the sensitivity. Here, a new sensor is introduced that is simple, rapid, sensitive and cost-effective for quantitation of chlorpromazine.
    Keywords: Chlorpromazine, Voltammetry, Graphene oxide, Glassy carbon electrode
  • Mohammad Mazloum, Ardakani *, Mozhgan Yavari, Alireza Khoshroo Pages 183-193
    The improvement of nanotechnology has been increasing along the last years and nanostructured materials have important consideration due to their unique properties. In this work, for the first time, a novel construction procedure for urea oxidation based on titanium dioxide (TiO2) nanofibers (NFs) decorated Ni nanoparticles (NiNPs) is reported. Nickel nanoparticles were electrodeposed on the surface of titanium dioxide nanofibers (TNF-NiNPs) and the resulting modified electrode was characterized by scanning electron microscopy (SEM). Urea electro-oxidation reaction in NaOH solution on (TNF-NiNPs) as electrode is studied by cyclic voltammetry (CV) and chronoamperometry (CA) method. The surface coverage of TNF-NiNPs /GC electrode was calculated to be г*a =4.16× 10-7 mol cm2, which is higher than corresponding value reported for the urea biosensor using Ni matrix. The electrochemical results showed that the presented electrode is effective and has good electrocatalytic activity for urea oxidation and the structures of nanofibers have great effect on the electrooxidation of urea.
    Keywords: Urea electrooxidation, Electrospinning, Nickel nanoparticles, Titanium dioxide nanofiber
  • Gamze Colak, Vedia Nüket Tirtom * Pages 195-213
    In this work, two different adsorbent were comparatively used and developed preconcentration of ultra-trace levels of copper ions by flow injection analyses for atomic absorption spectrometry. Copper ions were preconcentrated on a mini-column packed with epichlorohydrin cross-linked silica gel-chitosan composite beads and epichlorohydrin cross linked multiwalled carbon nanotubes-chitosan composite beads. 0.1 M Ethylene diamine tetra acetic acid and 0.1 M nitric acid solutions were used in order to remove the copper ions from the adsorbents. The factors affecting preconcentration of copper (II) ions such as sample and eluent flow rate, loading time, pH, eluent concentration, interfering ions were investigated. Under the optimized parameters, detection limits of the methods were obtained as 2 ng mL−1 for epichlorohydrin cross linked silica gel-chitosan composite beads and 1.3 ng mL−1 for epichlorohydrin cross linked multiwalled carbon nanotubes-chitosan composite beads with enrichment factor of 23 and 19.2 respectively. The recoveries and intra-day and inter-day precisions for copper ions were >90.0% and >3% respectively. In order to validate the developed methods, a certified reference material of drinking water, was analyzed and the determined values were in good agreement with the certified values. The developed methods have also been applied to the determination of copper (II) ions in Gediz River in Turkey with satisfactory results.
    Keywords: Copper, Flow injection analyses, Silica gel-chitosan composite beads, Carbon nanotube-chitosan beads, Online preconcentration
  • Adib Ghaleb *, Adnane Aouidate, Mohammed Bouachrine, Tahar Lakhlifi, Abdelouahid Sbai Pages 215-229
    Heterocyclic moieties become more interesting for chemists, pharmacologists, microbiologists, and other researchers owing to its indomitable biological potential as anti-infective agents. Among heterocyclic compounds, there is 1,2,3‐triazole nucleus which is one of the most important and well‐known heterocycles. Triazole core is considered as essential structure in medicinal chemistry and is widely used to synthesize molecules with medical benefits. In this work, a set of triazole analogues were identified as anti-tubercular agents through a series of computer-aided drug design processes, including three-dimensional quantitative structure–activity relationship (3D-QSAR) modeling, molecular docking and ADMET study to determine properties of these new proposed drugs. The CoMFA and CoMSIA models employed for a training set of 25 compounds gives reliable values of Q2 (0.63 and 0.65 respectively) and R2 (0.85 and 0.71 respectively). These results indicate that the developed models possess good predictive ability. Based on the 3D-QSAR contours new molecules with high predicted activities were designed. Moreover, surflex-docking was applied to highlight the important interactions between the ligand and mycobacterium tuberculosis receptor, Therefore to confirm the stability of predicted molecules in the receptor. In silico ADMET results show good properties for these new anti-tubercular agents.
    Keywords: 3D-QSAR, Surflex-docking, In silico ADMET, Anti-tubercular, Triazole
  • Somayeh Makarem *, Behrooz Mirza, Zahra Mohammad Darvish, Nazila Amiri Notash, Somayeh Ashrafi Pages 231-240
    An electrochemical strategy is presented herein for the synthesis of pyran nanoparticles by an electro-generated base from a propanol anion in a one-pot, three-component reaction. This reaction includes the condensation of isatin or an aromatic aldehyde, ethyl acetoacetate, and malononitrile in propanol in the presence of sodium bromide as an electrolyte in an undivided cell. The effects of current, temperature, solvent, time and anode type were studied. The optimized current and temperature for the synthesis of spiropyrans nanoparticles is 20 mA/cm2 at 25 °C; for producing nanosized particles of 4H pyrans, it is 40 mA/cm2 at 50 °C. The formation of propanol anions on the surface of the cathode-generated malononitrile anion preceded the Knoevenagel condensation which is followed by a Michael addition and ended by the intramolecular ring-closing strategy. The products were characterized after purification using infrared spectroscopy (IR), 1H and 13C Nuclear magnetic resonance, scanning electron microscope (SEM), and dynamic light scattering (DLS). The proposed method produces pyrans nanoparticles directly from initial compounds in a safe and mild condition.
    Keywords: Electrochemical synthesis, Nanoparticles, Pyran, Malononitrile
  • Ghafoor Mihandoost, Mir Mahdi Zahedi *, Morteza Ziyaadini Pages 241-251
    In the present study, the transport of potassium salt as an important agricultural fertilizer was reported through a pseudo carbon nanotube supported liquid membrane using dibenzo-l8-crown-6 as the carrier. Single wall carbon nanotube was utilized as an additive to liquid membrane to form a pseudo support, while the extraction result showed a noticeable increase in the process rate. In order to find the best transport conditions, affecting parameters such as pH of the feed and receiving phases, type of membrane solvent, concentration of the carrier, stripping solution conditions, time, and temperature were investigated. In the optimum working conditions and after 80 min, 23.0(±0.1) % of K+ from the feed phase (containing K+ = 0.01 M, NaCl = 0.01 M, pH = 5.6) across a dichloromethane membrane (DB18C6 = 0.01 M) was transported into the receiving phase (containing HCl 1 M and NaCl = 0.01 M). The selectivity of the method was evaluated by performing the competitive transport experiments on the simulated mixtures containing the main ions with conservative concentration of seawater.
    Keywords: Potassium, Seawater, Pseudo supported liquid membrane, Carbon nanotube, Dibenzo-l8-crown-6