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1.
Mikrochim Acta ; 189(8): 267, 2022 07 02.
Article in English | MEDLINE | ID: mdl-35779180

ABSTRACT

A sensor was developed for the first time based on polydopamine nanospheres doped with I2, I-, and IO3- species (PDA-Iodine), to determine the concentration of p-aminophenol (p-AP), phenol (Ph), and p-nitrophenol (p-NP) simultaneously. These polymeric nanospheres were successfully characterized using a variety of techniques including field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared, Raman spectroscopy, and X-ray diffraction analysis. A carbon paste electrode was modified with the PDA-Iodine (CPE/PDA-Iodine). Because of the electrocatalytic activity of DA/DQ, I2 and I- species (in the structure of PDA-Iodine), CPE/PDA-Iodine shows enhancement in the electrooxidation peak currents as well as slight negative shift in peak potentials of p-AP, Ph, and p-NP compared with a bare carbon paste electrode. Under optimal experimental conditions, the linear calibration plots are linear in the ranges 0.5-120 µM for p-AP, 0.7-120 µM for Ph, and 1.0-100 µM for p-NP with limits of detection of 30, 40, and 80 nM for p-AP, Ph, and p-NP, respectively (S/N = 3). To prove the performance of the method, the repeatability of the signals of CPE/PDA-Iodine was evaluated and the RSD values obtained were 2.9%, 3.2%, and 3.1% for p-AP (45 µM), Ph (40 µM), and p-NP (40 µM), respectively. The CPE/PDA-Iodine is a promising new sensor for sensing p-AP, Ph, and p-NP simultaneously in tap and river water sample and the values of recoveries for spiked samples were in the range 94.0-104.4%.


Subject(s)
Iodine , Nanospheres , Aminophenols , Carbon/chemistry , Electrochemical Techniques/methods , Iodides , Nitrophenols , Phenol , Phenols
2.
Biosens Bioelectron ; 119: 163-169, 2018 Nov 15.
Article in English | MEDLINE | ID: mdl-30125877

ABSTRACT

Identification and quantitation of mephedrone as one of the popular new psychoactive substances (NPSs) in biological fluids is important. In this study, a novel electrochemical imprinted sensor was designed for ultrasensitive and selective measurement of mephedrone, based on sol-gel molecular imprinted polymer, polytyramine and functionalized multi-walled carbon nanotube@ gold nanoparticles (f-MWCNT@AuNPs) nanocomposite. The developed electrochemical sensor inherits characteristics of the gold and MWCNTs such as high electrical conductivity, large specific surface area and good biocompatibility. Also, tyramine as an additional monomer was used for fabrication of a strongly adhering film on the surface of the electrode. In the proposed method, the concentration of mephedrone was determined indirectly. The change in the current response of [Fe(CN)6]3-/4- redox probe in the presence and absence of mephedrone molecules was used for indirect measurement of mephedrone molecule in solution. Density functional theory (DFT) was applied to better understanding the interactions between the mephedrone, sol-gel polymer and tyramine from molecular viewpoint. Under the optimized experimental conditions, the calibration curve of the designed sensor was plotted and two dynamic linear ranges from 1 to 10 nM and 10-100 nM with a limit of detection (LOD) as low as 0.8 nM (142 pg ml-1) were obtained. Finally, the fabricated sensor was successfully used to detect the mephedrone in biological samples.


Subject(s)
Biosensing Techniques/methods , Electrochemical Techniques , Methamphetamine/analogs & derivatives , Electrodes , Gold/chemistry , Humans , Limit of Detection , Metal Nanoparticles/chemistry , Methamphetamine/analysis , Polymers/chemistry
3.
Mater Sci Eng C Mater Biol Appl ; 91: 10-18, 2018 Oct 01.
Article in English | MEDLINE | ID: mdl-30033236

ABSTRACT

Flutamide (FLT) is a non-steroidal anti-androgen drug that has a specific anti-androgenic activity so that it is used in the treatment of prostate cancer. FLT may also be used to treat excess androgen levels in women. A sensitive electrochemical sensor based on hyperbranchedpolyglycerol functionalized- graphene oxide developed, using ionic liquid mediated hollow fiber-pencil graphite electrode (HF/HBP-GO/PGE) as a working electrode for determination of an anticancer drug, flutamide (FLT. In this design, a two centimeter piece of porous polypropylene hollow fiber membrane was impregnated with ionic liquid (1-Pentyl-3-methylimidazoliumbromide), and a graphite rod modified with hyperbranchedpolyglycerol/graphene oxide (HBP-GO), was located inside the fiber lumen. The modified electrode exhibits sorption activity, high sensitivity, stability and applicability over a wide range of concentration of FLT. The morphology and the electrochemical properties of the modified electrode were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The effect of the amount of graphene oxide (GO), scan rate, pH, concentration of ionic liquid, extraction time and agitation rate on electrochemical behavior of flutamide molecules was investigated. The square wave voltammetric method showed a linear behavior over the drug concentration range 0.1-110 µM. The limit of detection (LOD) and the limit of quantification (LOQ) were found to be 0.029 µM and 0.099 µM, respectively. The proposed sensor was applied for determination of FLT in human plasma sample with satisfactory results.


Subject(s)
Antineoplastic Agents/blood , Biosensing Techniques , Electrochemical Techniques/methods , Flutamide/blood , Glycerol/chemistry , Graphite/chemistry , Microtechnology/instrumentation , Oxides/chemistry , Polymers/chemistry , Borates/chemistry , Electrodes , Flutamide/chemistry , Humans , Hydrogen-Ion Concentration , Imidazoles/chemistry , Ionic Liquids/chemistry , Limit of Detection , Reproducibility of Results , Solutions , Spectroscopy, Fourier Transform Infrared
4.
Anal Bioanal Chem ; 410(2): 429-439, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29214538

ABSTRACT

A selective and sensitive magnetic dispersive solid-phase microextraction (MDSPME) coupled with gas chromatography-mass spectrometry was developed for extraction and determination of organophosphorus pesticides (Sevin, Fenitrothion, Malathion, Parathion, and Diazinon) in fruit juice and real water samples. Zero valent Fe-reduced graphene oxide quantum dots (rGOQDs@ Fe) as a new and effective sorbent were prepared and applied for extraction of organophosphorus pesticides using MDSPME method. In order to study the performance of this new sorbent, the ability of rGOQDs@ Fe was compared with graphene oxide and magnetic graphene oxide nanocomposite by recovery experiments of the organophosphorus pesticides. Several affecting parameters in the microextraction procedure, including pH of donor phase, donor phase volume, stirring rate, extraction time, and desorption conditions such as the type and volume of solvents and desorption time were thoroughly investigated and optimized. Under the optimal conditions, the method showed a wide linear dynamic range with R-square between 0.9959 and 0.9991. The limit of detections, the intraday and interday relative standard deviations (n = 5) were less than 0.07 ngmL-1, 4.7, and 8.6%, respectively. The method was successfully applied for extraction and determination of organophosphorus pesticides in real water samples (well, river and tap water) and fruit juice samples (apple and grape juice). The obtained relative recoveries were in the range of 82.9%-113.2% with RSD percentages of less than 5.8% for all the real samples.


Subject(s)
Fruit and Vegetable Juices/analysis , Graphite/chemistry , Organophosphorus Compounds/analysis , Pesticides/analysis , Solid Phase Microextraction/methods , Water Pollutants, Chemical/analysis , Water/analysis , Gas Chromatography-Mass Spectrometry/methods , Iron/chemistry , Limit of Detection , Organophosphorus Compounds/isolation & purification , Oxidation-Reduction , Oxides/chemistry , Pesticides/isolation & purification , Quantum Dots/chemistry , Water Pollutants, Chemical/isolation & purification
5.
Mater Sci Eng C Mater Biol Appl ; 69: 653-60, 2016 Dec 01.
Article in English | MEDLINE | ID: mdl-27612758

ABSTRACT

This paper proposes a simple approach for sensing of citalopram (CTL) using gold-palladium bimetallic nanoparticles (Au-PdNPs) decorated graphene modified gold electrode. Au-PdNPs were deposited at the surface of a graphene modified gold electrode with simple electrodeposition method. The morphology and the electrochemical properties of the modified electrode were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersion spectroscopy (EDS), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and square wave voltammetry (SWV). The novel sensor exhibited an excellent catalytic activity towards the oxidation of CTL. The oxidation peak current of CTL, was linear in the range of 0.5-50µM with a detection limit 0.049µM with respect to concentration of citalopram. The proposed sensor was successfully applied for determination of CTL tablet and human plasma samples with satisfactory results.


Subject(s)
Citalopram/analysis , Electrochemical Techniques/methods , Gold/chemistry , Graphite/chemistry , Metal Nanoparticles/chemistry , Palladium/chemistry , Calibration , Citalopram/blood , Citalopram/chemistry , Electricity , Electrodes , Humans , Hydrogen-Ion Concentration , Limit of Detection , Metal Nanoparticles/ultrastructure , Oxidation-Reduction
6.
Anal Bioanal Chem ; 408(27): 7719-7729, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27562753

ABSTRACT

Ultrasonic-assisted magnetic dispersive solid-phase microextraction coupled with high performance liquid chromatography has been developed for extraction and determination of mirtazapine, N-desmethyl mirtazapine, and 8-hydroxy mirtazapine in human urine and water samples. Magnetic graphene oxide-polyaniline nanocomposite (MGOPA) as a novel SPME sorbent was synthesized and used for the microextraction process. The analytical performance of MGOPA was compared with magnetic graphene oxide nanocomposite and indicated that the new sorbent was quite effective for extraction of mirtazapine, N-desmethyl mirtazapine, and 8-hydroxy mirtazapine. A two-stage experimental design approach, Plackett-Burman screening design and Box-Behnken optimization design, was used for screening and optimizing of significant variables in the microextraction process. The practical applicability of the proposed method was assessed by studying the linearity, intra-day and inter-day accuracy, enrichment factor, and precision. This method can be satisfactorily applied to the determination of mirtazapine and its metabolites in human urine and environmental water samples. Graphical Abstract Magnetic graphene oxide-polyaniline nanocomposite.


Subject(s)
Antidepressive Agents, Tricyclic/urine , Mianserin/analogs & derivatives , Solid Phase Microextraction/methods , Water Pollutants, Chemical/analysis , Adsorption , Aniline Compounds/chemistry , Chromatography, High Pressure Liquid , Factor Analysis, Statistical , Fresh Water/chemistry , Graphite/chemistry , Healthy Volunteers , Humans , Magnets , Mianserin/urine , Mirtazapine , Nanocomposites/chemistry , Oxides/chemistry , Sonication
7.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1029-1030: 81-87, 2016 Sep 01.
Article in English | MEDLINE | ID: mdl-27428449

ABSTRACT

A new design of hyperbranched polyglycerol/graphene oxide nanocomposite reinforced hollow fiber solid/liquid phase microextraction (HBP/GO -HF-SLPME) coupled with high performance liquid chromatography used for extraction and determination of ibuprofen and naproxen in hair and waste water samples. The graphene oxide first synthesized from graphite powders by using modified Hummers approach. The surface of graphene oxide was modified using hyperbranched polyglycerol, through direct polycondensation with thionyl chloride. The ready nanocomposite later wetted by a few microliter of an organic solvent (1-octanol), and then applied to extract the target analytes in direct immersion sampling mode.After the extraction process, the analytes were desorbed with methanol, and then detected via high performance liquid chromatography (HPLC). The experimental setup is very simple and highly affordable. The main factors influencing extraction such as; feed pH, extraction time, aqueous feed volume, agitation speed, the amount of functionalized graphene oxide and the desorption conditions have been examined in detail. Under the optimized experimental conditions, linearity was observed in the range of 5-30,000ngmL(-1) for ibuprofen and 2-10,000ngmL(-1) for naproxen with correlation coefficients of 0.9968 and 0.9925, respectively. The limits of detection were 2.95ngmL(-1) for ibuprofen and 1.51ngmL(-1) for naproxen. The relative standard deviations (RSDs) were found to be less than 5% (n=5).


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/isolation & purification , Hair/chemistry , Ibuprofen/isolation & purification , Liquid Phase Microextraction/methods , Naproxen/isolation & purification , Solid Phase Microextraction/methods , Wastewater/analysis , Chromatography, High Pressure Liquid/methods , Glycerol/chemistry , Graphite/chemistry , Humans , Limit of Detection , Nanocomposites/chemistry , Oxides/chemistry , Polymers/chemistry , Water Pollutants/isolation & purification
8.
Anal Bioanal Chem ; 408(16): 4247-56, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27108286

ABSTRACT

A hollow fiber solid-phase microextraction method for pre-concentration of venlafaxine and o-desmethylvenlafaxine in biological matrices is described for the first time. The functionalized MWCNTs with an amino acid, glycine, were synthesized and held in the pore of a hollow fiber by sol-gel technique. In order to extract venlafaxine and o-desmethylvenlafaxine from real samples, the hollow fiber was immersed into the sample solution under a magnetic stirring for 20 min. The extracted venlafaxine and o-desmethylvenlafaxine from the fibers were then desorbed with methanol by sonication and analyzed using high-performance liquid chromatography. Important microextraction parameters including pH of donor phase, donor phase volume, stirring rate, extraction time, and desorption conditions such as the type and volume of solvents and desorption time were thoroughly investigated and optimized. The optimized technique provides good repeatability (RSD of the intraday precision 3.7 and 3.4, interday precision of 5.8 and 5.4 %), linearity of (0.1-300 and 0.2-360 ng mL(-1)), low LODs of (0.03 and 0.07 ng mL(-1)), and high enrichment factor of (164 and 176) for venlafaxine and o-desmethylvenlafaxine, respectively. The analytical performance of Gly-MWCNTs as a new SPME sorbent was compared with MWCNTs and carboxylic MWCNTs. The results indicate that Gly-MWCNTs are quite effective for extraction of venlafaxine and o-desmethylvenlafaxine. Feasibility of the method was evaluated by analyzing human urine and real water samples. The results obtained in this work show a promising, simple, selective, and sensitive sample preparation and determination method for biological and water samples.


Subject(s)
Antidepressive Agents/isolation & purification , Desvenlafaxine Succinate/isolation & purification , Glycine/chemistry , Nanotubes, Carbon/chemistry , Solid Phase Microextraction/methods , Urine/chemistry , Venlafaxine Hydrochloride/isolation & purification , Water Pollutants, Chemical/isolation & purification , Adsorption , Antidepressive Agents/analysis , Antidepressive Agents/urine , Chromatography, High Pressure Liquid , Desvenlafaxine Succinate/analysis , Desvenlafaxine Succinate/urine , Humans , Limit of Detection , Rivers/chemistry , Solid Phase Microextraction/instrumentation , Venlafaxine Hydrochloride/analysis , Venlafaxine Hydrochloride/urine , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/urine
9.
J Sep Sci ; 39(6): 1082-9, 2016 Mar.
Article in English | MEDLINE | ID: mdl-27027588

ABSTRACT

A simple, rapid, and sensitive method for the determination of naproxen and ibuprofen in complex biological and water matrices (cow milk, human urine, river, and well water samples) has been developed using ultrasound-assisted magnetic dispersive solid-phase microextraction. Magnetic ethylendiamine-functionalized graphene oxide nanocomposite was synthesized and used as a novel adsorbent for the microextraction process and showed great adsorptive ability toward these analytes. Different parameters affecting the microextraction were optimized with the aid of the experimental design approach. A Plackett-Burman screening design was used to study the main variables affecting the microextraction process, and the Box-Behnken optimization design was used to optimize the previously selected variables for extraction of naproxen and ibuprofen. The optimized technique provides good repeatability (relative standard deviations of the intraday precision 3.1 and 3.3, interday precision of 5.6 and 6.1%), linearity (0.1-500 and 0.3-650 ng/mL), low limits of detection (0.03 and 0.1 ng/mL), and a high enrichment factor (168 and 146) for naproxen and ibuprofen, respectively. The proposed method can be successfully applied in routine analysis for determination of naproxen and ibuprofen in cow milk, human urine, and real water samples.


Subject(s)
Ibuprofen/isolation & purification , Magnetics , Naproxen/isolation & purification , Solid Phase Microextraction/methods , Ultrasonics , Animals , Cattle , Chromatography, High Pressure Liquid , Equipment Design , Humans , Water Pollutants, Chemical/isolation & purification
10.
Molecules ; 16(9): 8130-42, 2011 Sep 22.
Article in English | MEDLINE | ID: mdl-21941227

ABSTRACT

The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide-acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log K(f) of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°(c) and DS°(c)) for formation of (p-isopropyl-calix[6]arene·Cs)+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs)+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.


Subject(s)
Acetonitriles/chemistry , Calixarenes/chemistry , Cesium/chemistry , Chelating Agents/chemistry , Chlorides/chemistry , Coordination Complexes/chemistry , Dimethyl Sulfoxide/chemistry , Cations , Conductometry , Solvents , Thermodynamics
11.
Anal Chim Acta ; 689(1): 122-8, 2011 Mar 09.
Article in English | MEDLINE | ID: mdl-21338767

ABSTRACT

A novel solid-phase microextraction technique using a hollow fiber-supported sol-gel combined with multi-walled carbon nanotubes was employed in the determination of phenobarbital in wastewater. In this new technique, a silica-based, organic-inorganic polymer containing functionalized multi-walled carbon nanotubes (MWCNTs) was prepared with sol-gel technology via the reaction of tetraethylorthosilicate (TEOS) with an acidic catalyst (HCl). This sol was injected into a polypropylene hollow fiber segment for in situ gelation. This device operated in direct immersion sampling mode. The experimental setup is simple and affordable, and the device is disposable, so there is no risk of cross-contamination or carry-over. Parameters affecting extraction such as pH of the aqueous solution, ageing and extraction times, aqueous sample volume, agitation speed and carbon nanotube amount were optimized. Linearity was observed over a range of 0.50-5000 ng mL(-1), with an estimation coefficient (r(2)) higher than 0.982. The limit of detection (LOD) was 0.32 ng mL(-1) (n=5), and repeatability (RSD%=2.9) was from the average of three levels of analyte concentrations (1, 1000 and 4500 ng mL(-1)) with three replicates for each within a single day. Finally, a pre-concentration factor of 2100 was obtained for phenobarbital.


Subject(s)
Nanotubes, Carbon/chemistry , Phenobarbital/analysis , Silanes/chemistry , Silicon Dioxide/chemistry , Solid Phase Microextraction/instrumentation , Limit of Detection , Nanotubes, Carbon/ultrastructure , Phase Transition , Polymers/chemistry , Reproducibility of Results , Sewage/chemistry , Solid Phase Microextraction/methods
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