Extraction and preconcentration of Ni(ii), Pb(ii), and Cd(ii) ions using a nanocomposite of the type Fe3O4@SiO2@polypyrrole-polyaniline.

In this study, the application of Fe3O4@SiO2@polypyrrole-polyaniline magnetic nanocomposite was studied for Ni(ii), Cd(ii), and Pb(ii) ions preconcentration extraction. In this regard, the silica layer prevents the Fe3O4 nanoparticles (NPs) from aggregating over a broad pH range value and simultaneously improves chemical stability and hydrophilicity. By using a Box-Behnken design, the effect of various parameters affecting the preconcentration was studied. FAAS was employed to quantify the eluted analytes. The detection limits are 0.09, 1.1, and 0.3 ng mL-1 for Ni(ii), Cd(ii) and Pb(ii), ions, respectively. The relative standard deviations (RSDs%) were calculated for determining the method's precision, lower than 7.5%. The capacities of sorption are 75, 84, and 98 mg g-1, respectively. With the usage of a certified reference material, the developed method was validated. After that, the validated method was employed to rapidly extract trace target ions from food samples and gave satisfactory results.

Magnetic porous carbon nanocomposite derived from cobalt based-metal-organic framework for extraction and determination of homo and hetero-polycyclic aromatic hydrocarbons.

Herein, a novel magnetic porous carbon nanocomposite derived from a cobalt based-metal-organic framework was synthesized and evaluated for simultaneous preconcentration of homo and hetero-polycyclic aromatic hydrocarbons. Briefly, magnetite nanoparticles (MNPs) were synthesized and then were coated with a metal-organic framework layer. Finally, the magnetic nanocomposite was carbonized under an inert atmosphere to obtain the magnetic porous carbon (MPC). Various characterization techniques such as FT-IR spectroscopy, transmission and scanning electron microcopies, vibrating sample magnetometry, and X-ray diffraction were employed. Applicability of the MPC was explored using benzothiophene, dibenzothiophene, 9,10-dimethylanthracene, and benz[α]anthracene as the model analytes. Limits of detection and linearities were achieved in the range of 0.06-0.18 µg L-1 and 0.25-500 µg L-1, respectively. Precision of the method as RSDs was evaluated which was in the range of 4.2-7.0% (within-day, n = 5) and 8.2-11.3% (between-day, n = 3). Ultimately, the method was applied to analyze two seawater samples and satisfactory results (RSDs%, 5.0-9.0%; relative recoveries, 89-104%) were obtained.

A novel polymer coated magnetic porous carbon nanocomposite derived from a metal-organic framework for multi-target environmental pollutants preconcentration.

This study describes the synthesis of a novel polymer (polypyrrole-polythiophene) coated magnetic porous carbon (MPC) composite derived from magnetic metal-organic framework (MOF) and its utilization in multi-target environmental pollutants preconcentration. In this regards, Fe3O4 nanoparticles (NPs) was used as magnetic core and Co-MOF-71 was coated on the surface of the NPs. Afterwards, magnetic MOF (MMOF) was carbonized under nitrogen atmosphere and finally MNC was coated with a polymer layer of the type polypyrrole-polythiophene to obtain the nanocomposite (MPC@PPy-PTh). Magnetic property, structure and morphology of MPC@PPy-PTh were explored via various characterization techniques. Applicability of MPC@PPy-PTh nanoadsorbent was investigated in multi-target environmental pollutants preconcentration using 4-chlorophenol 2-naphtol, 1-amino-2-naphthol, 2,4-dichloroaniline, 3,4-dichloroaniline, benzothiophene and naphthalene as the model analytes. Effect of experimental factors on the preconcentration of target pollutants was explored and optimized systematically. Under the optimized condition, LODs were obtained in the range of 0.06-0.18 µg L-1. The proposed method exhibited linearity within the range of 0.25-500 µg L-1. Repeatability of the new method based on the relative standard deviations (n = 5) was in the range of 3.4-9.0%. Finally, the analytical applicability of the optimized method was investigated in seawater and wastewater samples and satisfactory results were achieved.

Dispersive solid-phase extraction of buprenorphine from biological fluids using metal-organic frameworks and its determination by ultra-performance liquid chromatography.

In this work, various types of metal-organic frameworks were synthesized, and their affinities toward buprenorphine were evaluated using dispersive solid-phase extraction. The extracted buprenorphine was determined by ultra high performance liquid chromatography-ultraviolet detection system. The highest extraction recovery was observed by employing zeolitic imidazole framework-67. Then, a facile and fast extraction method was designed for the extraction and purification of the target drug. Optimization of the extraction method was carried out by the design of experiment approach. A linearity range of 1-1000 µg/L with the limit of detection of 0.15 µg/L and relative standard deviations (50 µg/L, n = 5) of 3.4% was obtained for standard sample analysis. Under optimized experimental and instrumental conditions, the relative recoveries were in the range of 95 to 111%. Eventually, zeolitic imidazole framework-67 was successfully employed for the extraction and determination of buprenorphine in the biological fluids with satisfactory results.

The efficient removal of methylene blue from water samples using three-dimensional poly (vinyl alcohol)/starch nanofiber membrane as a green nanosorbent.

In the present study, a simple, fast, and economical method was introduced to eliminate methylene blue from dye wastewater water using a non-toxic, inexpensive, stable, and efficient adsorbent. The poly (vinyl alcohol) (PVA)/starch hydrogel nanofiber membrane with high surface area and the three-dimensional structure was fabricated in water via electrospinning strategy, and the cross-linking reaction was done by thermal treatment. The characterization of the nanofibers was carried out using Fourier-transform infrared spectrometer (FT-IR) and field-emission scanning electron microscopy (FE-SEM), and the cross-linked PVA/starch nanofiber was applied as a membrane for the removal of methylene blue (MB). The recovery of MB was performed by methanol solution containing 5% (v/v) HCl. Langmuir isotherm model successfully described the adsorption of MB on nanosorbent, and the maximum adsorption capacity (qm) was 400 mg g-1. Also, the kinetic of adsorption was well fitted by the pseudo-second-order model. In this study, because of the high stability of fabricated membrane (based on the tensile testing), it can be used as a filter for the fast separation of MB (cationic dye) and methyl orange (MO, anionic dye). Graphical abstract.

Preparation of magnetite/multiwalled carbon nanotubes/metal-organic framework composite for dispersive magnetic micro solid phase extraction of parabens and phthalate esters from water samples and various types of cream for their determination with liquid chromatography.

In the current study, MMWCNTs@MIL-101(Cr) (Fe3O4/multiwalled carbon nanotubes/MIL-101(Cr)) was synthesized and utilized as a new sorbent for the first time. It was employed successfully for the extraction of parabens and phthalate esters (PEs) from water and cream samples prior to their quantification with HPLC-DAD. The prepared metal-organic-framework (MOF) was characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), EDX mapping, thermogravimetric analysis (TGA), vibrating-sample magnetometer (VSM) and X-ray powder diffraction (XRD). Three phthalate esters (dimethyl phthalate (DMP), diethyl phthalate (DEP), diallyl phthalate (DAP)) and two parabens (methylparaben (MP) and butylparaben (BP)) were chosen as model analytes. Several experimental factors affecting the extraction efficiency, including pH value, nanosorbent amount, sorption time, salt concentration, sample volume, type and volume of the eluent, and elution time were investigated. The optimization of the extraction method was carried out by response surface methodology (RSM) and desirability function (DF) approach. Under the opted conditions, the method was linear in the range of 0.1-1500 µg L-1 with coefficients of determination > 0.9991. The limits of detection of PEs and parabens were found in the range of 0.03-0.15 µg L-1 (S/N = 3). The relative standard deviations were less than 7.5% and the extraction recoveries ranged from 38.04 to 70.62%. The present method was simple, rapid, inexpensive and environmentally friendly and was successfully utilized for the determination of PEs and parabens in water samples and various types of cream samples with satisfactory results.

A nanosized magnetic metal-organic framework of type MIL-53(Fe) as an efficient sorbent for coextraction of phenols and anilines prior to their quantitation by HPLC.

The authors describe the synthesis of a magnetic metal-organic framework (MOF) of type MIL-53(Fe) for coextraction of phenols and anilines from various environmental samples. A quick method for dispersive micro-solid phase extraction (D-µ-SPE) was developed for coextraction of the analytes 4-nitrophenol (4-NP), 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 1-amino-2-naphtol (1-A2N) and 2, 4-dichloroaniline (2, 4-DCA). The MOF was characterized by SEM, TEM, FT-IR, EDS, thermogravimetry, VSM and XRD. The method was optimized by response surface methodology combined with desirability function approach, specifically with respect to pH value of the sample, amount of sorbent, sorption time, salt concentration, sample volume, type and volume of the eluent, and elution time. Following elution with acetonitrile, the analytes were quantified by HPLC with photodiode array detection. Responses are linear in 0.1-2000 µg·L-1 concentration ranges. The limits of detection and relative standard deviations (for n = 5) are in the range of 0.03-0.2 µg·L-1 and 3.5-12.6%, respectively. Enrichment factors are 113, 61, 87, 144 and 114 for 4-NP, 4-CP, 4-CA, 1-A2N and 2,4-DCA, respectively. Recoveries from spiked samples ranged from 39.5 to 93.3%. The magnetic sorbent was successfully applied to the coextraction and determination of the analytes in river, rain and hookah water samples. Graphical abstract Schematic presentation for the synthesis of (a) Fe3O4 nanoparticles (NPs) and (b) Fe3O4@MIL-53(Fe). Fe3O4@MIL-53(Fe) was employed as a new nanosorbent in dispersive micro-solid phase extraction of phenols and anilines. The limits of detection are in the range of 0.03-0.2 µg·L-1.

Designing graphene-wrapped NiCo2Se4 microspheres with petal-like FeS2 toward flexible asymmetric all-solid-state supercapacitors.

Herein, we proposed a desirable strategy for the synthesis of graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (FeS2) (negative electrode) on nickel foam substrates. The positive electrode represents a substantial specific capacitance of 2112.30 F g-1 and excellent durability (6.8% loss after 5000 cycles). Furthermore, the negative electrode reflects good electrochemical performance with a specific capacitance of 321.30 F g-1 and a satisfactory rate capability of 47% capacitance retention. Considering the notable properties of the electrodes, a flexible asymmetric all-solid-state device based on graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (negative electrode) was assembled. Our flexible device exhibits the high specific capacitance of 221.30 F g-1, the significant energy density of 78.68 W h kg-1 and excellent flexibility.

Synthesis and characterization of a poly(p-phenylenediamine)-based electrospun nanofiber for the micro-solid-phase extraction of organophosphorus pesticides from drinking water and lemon and orange juice samples.

A new micro-solid-phase extraction sorbent was synthesized by electrospinning poly(p-phenylenediamine)/poly(vinyl alcohol) in the presence of cetyltrimethylammonium bromide. The modified nanofiber was prepared by removing the majority of the poly(vinyl alcohol) from the nanofiber blend by exposing it to the hot water. Scanning electron microscopy and surface analysis were performed to study the homogeneity and porosity of the electrospun nanofiber. In addition, Fourier transform infrared spectroscopy was applied for more characterization. The capability of the new nanofiber was explored by applying it in the extraction and preconcentration of organophosphorus pesticides from aqueous medium. After solvent desorption, the extracted analytes were analyzed by high-performance liquid chromatography with diode array detection. Under the optimum conditions, the relative standard deviation values at the concentration level of 50 ng/mL were in the range of 4.8-8.3%. The calibration curve showed linearity in the range of 0.5-500 ng/mL, and the limits of detection (S/N = 3) for the studied compounds were 0.15 ng/mL. By analyzing Tehran drinking water, lemon juice, sour lemon juice, orange juice and sour orange juice, the applicability of the presented method was investigated and the relative recoveries were in the range of 76-102%.

A poly(4-nitroaniline)/poly(vinyl alcohol) electrospun nanofiber as an efficient nanosorbent for solid phase microextraction of diazinon and chlorpyrifos from water and juice samples.

4-Nitroaniline was electropolymerized in a weakly alkaline medium, and the resulting poly(4-nitroaniline) (P4-NA)) was used to fabricate - by electrospinning - a nanofiber consisting of P4-NA and poly(vinyl alcohol) (PVA). The PVA fraction was then dissolved in hot water and this causes the porosity of electrospun nanofiber to be largely enhanced. The resulting nanofiber was utilized as a sorbent for solid phase microextraction of the model organophosphorus pesticides diazinon and chloropyrifos from aqueous media. The extracted analytes were then analyzed by corona discharge ion mobility spectrometry (CD-IMS). Under the optimized conditions, the limits of detection (at S/N = 3; for n = 10) are 0.4 and 0.6 ng mL-1 for diazinon and chloropyrifos, respectively. The relative standard deviations at the levels of 25, 50 and 100 ng mL-1 (for n = 3) ranged from 4.0-12.3% (both intra-day and inter-day). Eventually, the method was used to analyze different water samples, including spiked drinking water, sea water, lagoon water, and groundwater sample in the proximity of rice fields, and in two juice samples. Recoveries ranged between 82 and 102%. Graphical abstract An electrospun nanofiber consisting of highly porous poly(4-nitroaniline) was synthesized and used as a sorbent for solid phase microextraction of diazinon and chlorpyrifos from water and juice samples prior to quantitation by corona discharge ion mobility spectrometry.

Highly efficient electrochemical determination of propylthiouracil in urine samples after selective electromembrane extraction by copper nanoparticles-decorated hollow fibers.

In this work, a novel, inexpensive and fast strategy was described for selective and effective extraction and determination of propylthiouracil (PTU) with a high polarity (log P = 1.2) based on electromembrane extraction (EME) followed by differential pulse voltammetry (DPV). For this purpose, copper nanoparticles (CuNPs)-decorated hollow fiber was used as the selective membrane for EME of PTU in urine samples. The influential parameters on extraction such as extraction solvent, pH, agitation speed, applied potential and extraction time were systematically investigated. In optimized conditions, acceptable linearity was attained between 0.05 and 5 µg mL-1 (R2 value = 0.9994); moreover, superb enrichment factor (200) and repeatability (RSD%, n = 4, 5.7%) for 0.1 µg mL-1 of PTU solution were in desirable range. In addition, extraction recovery of 80.0% was achieved in this condition and the limit of detection (S/N ratio of 3:1) was 0.02 µg mL-1. Finally, the proposed method was successfully applied to determine PTU concentration in urine samples.

Dispersive magnetic solid-phase extraction of phthalate esters from water samples and human plasma based on a nanosorbent composed of MIL-101(Cr) metal-organic framework and magnetite nanoparticles before their determination by GC-MS.

In this study, a magnetic metal-organic framework was synthesized simply and utilized in the dispersive magnetic solid-phase extraction of five phthalate esters followed by their determination by gas chromatography with mass spectrometry. First, MIL-101(Cr) was prepared hydrothermally in water medium without using highly corrosive hydrofluoric acid, utilizing an autoclave oven heat supply. Afterward, Fe3 O4 nanoparticles were decorated into the matrix of MIL-101(Cr) to fabricate magnetic MIL-101 nanocomposite. The nanocomposite was characterized by various techniques. The parameters affecting dispersive magnetic solid-phase extraction efficiency were optimized and obtained as: a sorbent amount of 15 mg; a sorption time of 20 min; an elution time of 5 min; NaCl concentration, 10% w/v; type and volume of the eluent 1 mL n-hexane/acetone (1:1 v/v). Under the optimum conditions detection limits and linear dynamic ranges were achieved in the range of 0.08-0.15 and 0.5-200 µg/L, respectively. The intra- and interday RSD% values were obtained in the range of 2.5-9.5 and 4.6-10.4, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of the model analytes in water samples, and human plasma in the range of microgram per liter and satisfactory results were obtained.

Dispersive micro-solid phase extraction of aromatic amines based on an efficient sorbent made from poly(1,8-diaminonaphtalen) and magnetic multiwalled carbon nanotubes composite.

In this work, the extraction of aromatic amines with an efficient magnetic multiwalled carbon nanotubes/Fe3O4@Poly(1,8-diaminonaphtalen) (MWCNTs/Fe3O4@PDAN) composite followed by HPLC-DAD was presented. Imprimis, the comparison among different magnetic nanosorbents including Fe3O4, MWCNTs/Fe3O4, Fe3O4@PDAN and MWCNTs/Fe3O4@PDAN was conducted. The obtained results, exhibited that the MWCNTs/Fe3O4@PDAN composite has the highest extraction efficiency for target analytes (3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline). This sorbent was characterized by Fourier transform infrared spectroscopy, X-ray dispersive spectroscopy, thermogravimetry analysis, scanning electron microscopy, transition electron microscopy, vibrating sample magnetometry and X-ray diffraction. Design of experiment approach was applied to find out the optimal experimental conditions. The optimal extraction conditions were: pH of the sample, 10; sorbent amount, 10mg; sorption time, 15min; salt concentration, 10% w/w; type and volume of the eluent, 0.01molL-1 HCl in acetonitrile, 145µL; elution time; 2min. Under the optimal extraction conditions detection limits and linear dynamic ranges were achieved in the range of 0.1-0.25µgL-1 and 0.25-500µgL-1, respectively. The percent of extraction recovery and relative standard deviations (n=5) were in the range of 31.2-82.8% and 3.4-5.6%, respectively. Finally, the applicability of the method was successfully confirmed by the extraction and determination of target analytes in various water samples.

SiO2-coated magnetic graphene oxide modified with polypyrrole-polythiophene: A novel and efficient nanocomposite for solid phase extraction of trace amounts of heavy metals.

The synthesis of a novel nanocomposite comprised of SiO2-coated magnetic graphene oxide modified with a pyrrole-thiophene (mGO/SiO2@coPPy-Th) copolymer is reported in the present work. The nanocomposite was applied for the fast magnetic solid phase extraction (MSPE) of trace levels of copper, lead, chromium, zinc and cadmium from water and agricultural samples. The nanocomposite was prepared in three steps: (1) decoration of graphene oxide sheets with magnetite nanoparticles thorough a facile one-step chemical reaction strategy; (2) chemical grafting by a silica layer to obtain high stability in acidic solutions; and (3) surface modification by coPPy-Th via simultaneous oxidation polymerization of pyrrole and thiophene in the presence of mGO/SiO2 composite. The nanocomposite was subsequently characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and vibrating sample magnetometry (VSM) techniques. Several important experimental variables that could affect MSPE performance, including the pH of the sample, sorption time, sorbent dosage, eluent type and its concentration, eluent volume and elution time, were investigated and optimized. Under optimal conditions, the limits of detection for the target heavy metals ranged from 0.15 to 0.65µgL-1. The maximum sorption capacity of the mGO/SiO2@coPPy-Th nanocomposite was 201, 230, 125, 98 and 80mgg-1 for Cu(II), Pb(II), Zn(II), Cr(III) and Cd(II), respectively. Finally, the feasibility of the proposed method was investigated for the extraction and determination of the target metals from real matrices.

A Simple and Fast Method Based on New Magnetic Ion Imprinted Polymer as a Highly Selective Sorbent for Preconcentration and Determination of Cadmium in Environmental Samples.

BACKGROUND: The analysis of heavy metals at trace level is one of the main toxicologists concern, due to their vital rules in human`s life. Cadmium is one of these toxic heavy metals, which released to the environment from various industries. METHODS: In order to determine Cd (II) ions in various matrices magnetic ion-imprinted polymer (IIP) method has been developed and applied. This nano-sorbent has been synthesized by coating an IIP compound on Fe3O4 nanoparticles core to achieve highest surface area. This polymer has been used to evaluate Cd (II) levels in food, river, and wastewater in Tehran, Iran. RESULTS: Fe3O4@Cd-IIP was stable up to 300 °C. The various factors such as sample pH (optimized as 7), elution/sorption time (5 min), eluent amount (4 mL HCL), and its concentration (2 mol L-1) were optimized. Analysis instrument in all steps was Flame Atomic Abortion Spectrophotometer (FAAS). In this study, the detection limit was determined down to 0.6 µg L-1. CONCLUSION: This method was applied successfully for the preconcentration and determination of Cd (II) ions in environmental samples obtained from rivers, various foods and wastewater. In addition, the accuracy of the method was confirmed by analyzing a certified reference material (Seronorm LOT NO2525) and spiked real samples.

An efficient approach to selective electromembrane extraction of naproxen by means of molecularly imprinted polymer-coated multi-walled carbon nanotubes-reinforced hollow fibers.

In this work, a novel microextraction technique using molecularly imprinted polymer-coated multi-walled carbon nanotubes (MIP-MWCNTs) in electromembrane extraction (EME) procedure is described. The method in combination with HPLC-UV was utilized to determine naproxen, as an acidic model drug, in urine, plasma and wastewater samples. For this purpose, MIP-MWCNTs were placed in the pores of polypropylene hollow fiber. The MIP-MWCNTs-EME method has the advantages of high selectivity and cleanup of MIP along with high enrichment ability of the EME in a single step extraction. Continuing with the research, optimization of the factors affecting the migration of naproxen from sample solutions to MIP-MWCNTs sites and then into the lumen of hollow fiber was explored. Under the optimized conditions, the limit of detection (LOD) of the developed method was calculated to be 0.3µgL-1. All relative standard deviations (RSDs) were lower than 3%. Linearity of the method was obtained within the range of 1-1000µgL-1 with the coefficient of determination (r2) being higher than 0.999. Under the optimized conditions, an extraction recovery of 66% was obtained, which corresponded to a preconcentration factor of 88. Finally, the developed method was satisfactorily used to determine naproxen in urine, plasma and wastewater samples.

Magnetic molecularly imprinted composite for the selective solid-phase extraction of p-aminosalicylic acid followed by high-performance liquid chromatography with ultraviolet detection.

A new method for the selective extraction of p-aminosalicylic acid from aqueous and urine samples has been developed using magnetic molecularly imprinted polymer nanoparticles before determination by high-performance liquid chromatography. The Fe3 O4 nanoparticles were first prepared through the chemical coprecipitation of Fe2+ and Fe3+ and then coated with a vinyl shell. Subsequently, a layer of molecularly imprinted polymers was grafted onto the vinyl-modified magnetic nanoparticles by precipitation polymerization. FTIR spectroscopy, scanning electron microscopy, vibrating sample magnetometry, and thermogravimetric analysis were applied to characterize the sorbent properties. Moreover, the predominant parameters affecting the magnetic solid phase extraction such as sample pH, sorption and elution times, the amount of sorbent, and composition and volume of eluent were investigated thoroughly. The maximum sorption capacity of the imprinted polymer toward p-aminosalicylic acid was 70.9 mg/g, which is 4.5 times higher than that of the magnetic nonimprinted polymer. The magnetic molecularly imprinted polymer nanoparticles were applied for the selective extraction of p-aminosalicylic acid from aqueous and urine samples and satisfactory results were achieved. The results illustrate that magnetic molecularly imprinted polymer nanoparticles have a great potential in the extraction of p-aminosalicylic acid from environmental and biological matrices.

Poly(2-aminobenzothiazole)-coated graphene oxide/magnetite nanoparticles composite as an efficient sorbent for determination of non-steroidal anti-inflammatory drugs in urine sample.

In this study, for the first time, 2-aminobenzothiazole monomer was polymerized on Fe3O4 NPs, graphene oxide/Fe3O4 (GO/Fe3O4) and graphene/Fe3O4 (G/Fe3O4) nanocomposites. The synthesized magnetic nanosorbents were characterized by various techniques. The extraction ability of these nanosorbents including Fe3O4, GO/Fe3O4, G/Fe3O4, Fe3O4@poly(2-aminobenzothiazole) (Fe3O4@PABT), GO/Fe3O4@PABT and G/Fe3O4@PABT were compared for dispersive-micro-solid phase extraction of three non-steroidal anti-inflammatory drugs. The results revealed that GO/Fe3O4@PABT nanocomposite demonstrates higher extraction efficiency for naproxen, diclofenac and ibuprofen as selected model analytes. Following the sorption and elution steps, the model analytes were quantified by high performance liquid chromatography-photo diode array detection. Afterwards, a central composite design methodology combined with desirability function approach was applied to find out the optimal experimental conditions. Under the optimized conditions, the limits of detection and linear dynamic ranges were achieved in the range of 0.07-0.3 µg L(-1) and 0.25-2000 µg L(-1), respectively. The percent of extraction recovery was 87.4, 85.5 and 90.5% for naproxen, diclofenac and ibuprofen, respectively. The obtained relative standard deviation (n=5) was 7.2, 5.4 and 6.4% for naproxen, diclofenac and ibuprofen, respectively. Ultimately, this method was employed for urinary monitoring of the target analytes and satisfactory results were obtained.

A simple and fast method based on mixed hemimicelles coated magnetite nanoparticles for simultaneous extraction of acidic and basic pollutants.

One of the considerable and disputable areas in analytical chemistry is a single-step simultaneous extraction of acidic and basic pollutants. In this research, a simple and fast coextraction of acidic and basic pollutants (with different polarities) with the aid of magnetic dispersive micro-solid phase extraction based on mixed hemimicelles assembly was introduced for the first time. Cetyltrimethylammonium bromide (CTAB)-coated Fe3O4 nanoparticles as an efficient sorbent was successfully applied to adsorb 4-nitrophenol and 4-chlorophenol as two acidic and chlorinated aromatic amines as basic model compounds. Using a central composite design methodology combined with desirability function approach, the optimal experimental conditions were evaluated. The opted conditions were pH = 10; concentration of CTAB = 0.86 mmol L(-1); sorbent amount = 55.5 mg; sorption time = 11.0 min; no salt addition to the sample, type, and volume of the eluent = 120 µL methanol containing 5% acetic acid and 0.01 mol L(-1) HCl; and elution time = 1.0 min. Under the optimum conditions, detection limits and linear dynamic ranges were achieved in the range of 0.05-0.1 and 0.25-500 µg L(-1), respectively. The percent of extraction recoveries and relative standard deviations (n = 5) were in the range of 71.4-98.0 and 4.5-6.5, respectively. The performance of the optimized method was certified by coextraction of other acidic and basic compounds. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of the target analytes in various water samples, and satisfactory results were obtained.

Surfactant-assisted dispersive liquid-liquid microextraction of nitrazepam and lorazepam from plasma and urine samples followed by high-performance liquid chromatography with UV analysis.

Surfactant-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with UV detection has been developed for the simultaneous preconcentration and determination of lorazepam and nitrazepam in biological fluids. In this study, an ionic surfactant (cetyltrimethyl ammonium bromide) was used as an emulsifier. The predominant parameters affecting extraction efficiency such as the type and volume of extraction solvent, the type and concentration of surfactant, sample pH, and the concentration of salt added to the sample were investigated and opted. Under the optimum conditions (extraction solvent and its volume, 1-octanol, 70 µL; surfactant and its concentration, 1 mL of ultra-pure water containing 2 mmol L-1 cetyltrimethyl ammonium bromide; sample pH = 9 and salt content of 10% NaCl w/v), the preconcentration factors were obtained in the range of 202-241 and 246-265 for nitrazepam and lorazepam, respectively. The limits of quantification for both drugs were 5 µg L-1 in water sample and 10 µg L-1 in biological fluids with R2 values higher than 0.993. The suitability of the proposed method was successfully confirmed by the extraction and determination of the target drugs in human urine and plasma samples in the range of microgram per liter.