Dispersive micro solid phase extraction of glibenclamide from plasma, urine, and wastewater using a magnetic molecularly imprinted polymer followed by its determination by a high-performance liquid chromatography-photodiode array detector.

The present study describes the development of a simple and selective analytical method for dispersive micro solid phase extraction and determination of glibenclamide (GLB) using magnetic molecularly imprinted polymer (MMIP) as a sorbent. MMIP was fabricated by the non-covalent method on the surface of silicated FeO and had a high affinity for glibenclamide; dual monomers, itaconic acid and allylamine, were used for this. Polymerization was achieved by the precipitation method in the presence of glibenclamide as the template and ethylene glycol dimethacrylate as the cross-linker.

Design and manufacture of new hybrid hydrogel and superabsorbent polymer for controlled release of fulvic acid based on grafted xanthan gum/gelatin using electron irradiation and its use in fodder corn cultivation.

A humic acid-gelatin (HA-Gel) hydrogel, a gallic acid-xanthan gum (GA-XG) hydrogel, a HA-Gel/GA-XG hydrogel, and superabsorbent polymer (SAP) of HA-Gel/GA-XG/polyacrylamide (PAM) hydrogel were synthesized using electron beam irradiation method. The capability of synthesized hydrogels in loading and controlled release of fulvic acid (FA) was studied. The chemical and physical structure of sorbents was confirmed by various analyses.

Polyamidoamine with a hyper-branched structure grafted on modified magnetic graphene oxide for the trace separation of diclofenac and acetaminophen followed by high-performance liquid chromatography determination.

Different generations of polyamidoamine dendrimers were synthesized on a focal core of magnetic graphene oxide modified with 3-aminopropyltriethoxysilane. After the characterization of synthesized dendrimers, its second generation was employed as a suitable sorbent for simultaneous separation/preconcentration of diclofenac and acetaminophen by a dispersive magnetic solid phase microextraction. The extracted analytes were then quantified by high-performance liquid chromatography with ultraviolet detection.

Synthesis of magnetic molecular imprinted polymer with a new functional monomer for dispersive micro solid phase extraction of captopril from wastewater and biological samples and determination by UV-Vis spectrophotometry.

A magnetic molecularly imprinted polymer (MMIP) was fabricated for captopril by surface polymerization of FeO@SiO nanoparticles using a new functional monomer of N-(allylcarbamothioyl)-2-chlorobenzamide. It was then employed as a selective nanosorbent for dispersive magnetic micro solid phase extraction (DM-μ-SPE) of captopril from biological and wastewater samples. To characterize the physicochemical properties of the MMIP, different analytical methods such as the vibrating sample magnetometer, field emission scanning electron microscopy, Brunauer-Emmett-Teller, and Fourier transform infrared spectroscopy were utilized.

A Selective Fluorescent Nanoprobe Based on Graphene Quantum Dots and Hg for the Determination of Tetracycline in Biological Samples.

A simple, sensitive, and selective fluorometric method based on graphene quantum dots and Hg is presented for the determination of tetracycline. The fluorescence emission of graphene quantum dots at 463 nm decreased in the presence of Hg ions due to its electrostatic interaction with the negatively charged surface of quantum dots at pH = 8.0.

Chemiluminescence determination of dopamine using N, P-graphene quantum dots after preconcentration on magnetic oxidized nanocellulose modified with graphene quantum dots.

A novel sorbent consisting of magnetic oxidized nanocelluloses modified with graphene quantum dots was prepared and used for the separation and preconcentration of dopamine. The eluted dopamine from the sorbent was determined by a designed chemiluminescence system containing luminol, HO, Fe, and graphene quantum dots doped with nitrogen and phosphorus. Graphene quantum dots cause an increase in the intensity of the chemiluminescence system of luminol-HO, but the presence of Fe ions in this system decreases its intensity because of the sorption of the Fe ions on the surface of P, N-graphene quantum dots.

Selective and Sensitive Fluorometric Determination of Piroxicam Based on Nitrogen-doped Graphene Quantum Dots and Gold Nanoparticles Coated with Phenylalanine.

In this study, a sensitive fluorimetric method is proposed for the determination of piroxicam using nitrogen graphene quantum dots (N-GQDs) and gold nanoparticles coated with phenylalanine. The fluorescence emission of N-GQDs at 440 nm decreases with the increase of gold nanoparticles coated with phenylalanine. However, the addition of piroxicam causes the release of gold nanoparticles from the surface of quantum dots followed by the retrieval of the fluorescence emission of N-GQDs.

Determination of lamotrigine by fluorescence quenching of N-doped graphene quantum dots after its solid-phase extraction using magnetic graphene oxide.

A sensitive fluorescent nanoprobe is reported for the determination of lamotrigine after its preconcentration by magnetic graphene oxide nanocomposite. The fluorescent nanoprobe is based on the quenching effect of lamotrigine on the nitrogen graphene quantum dots fluorescence at 440 nm, through strong hydrogen bonding. Under optimum conditions, the quenching fluorescent intensity of nitrogen graphene quantum dots shows linearity with the lamotrigine concentration in the range of 2.

Fabrication of a sensitive colorimetric nanosensor for determination of cysteine in human serum and urine samples based on magnetic-sulfur, nitrogen graphene quantum dots as a selective platform and Au nanoparticles.

A novel colorimetric nanosensor is reported for the selective and sensitive determination of cysteine using magnetic-sulfur, nitrogen graphene quantum dots (FeO/S, N-GQDs), and gold nanoparticles (Au NPs). Thus, S, N-GQDs was firstly immobilized on FeO nanoparticles through its magnetization in the presence of Fe in the alkali solution. The prepared FeO/S, N-GQDs were dispersed in cysteine solution resulting in its quick adsorption on the surface of the FeO/S, N-GQDs through hydrogen bonding interaction.

Carbon dots doped by nitrogen and sulfur for dual-mode colorimetric and fluorometric determination of Fe and histidine and intracellular imaging of Fe in living cells.

The first dual-modality highly intensive fluorescent and colorimetric nanoprobe for Fe ions and histidine is reported. The carbon dots doped by nitrogen and sulfur (N,S-CDs) prepared by the one-pot hydrothermal method have an excitation/emission wavelength of 320/420 nm with 56% quantum yield. N,S-CDs exhibit strong visible fluorescence with high stability at pH ~ 7.

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.

Design of a pseudo stir bar sorptive extraction using graphenized pencil lead as the base of the molecularly imprinted polymer for extraction of nabumetone.

Molecularly imprinted polymer (MIP) was synthesized through the coprecipitation method on the graphene oxide anchored pencil lead as a substrate for the first time and applied as an efficient sorbent for pseudo stir bar sorptive extraction of nabumetone. The extracted analyte was determined by a novel spectrophotometric method based on the aggregation of silicate sol-gel stabilized silver nanoparticles in the presence of the analyte. The synthesized polymer was characterized using Fourier transform infrared spectroscopy and field emission scanning electron microscopy.

Doxycycline drug delivery using hydrogels of O-carboxymethyl chitosan conjugated with caffeic acid and its composite with polyacrylamide synthesized by electron beam irradiation.

Two hydrogels of O-carboxymethyl chitosan conjugated with caffeic acid and its composite with polyacrylamide were synthesized using electron beam irradiation. The synthesized hydrogels were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and mechanical properties studies. The hydrogels were loaded with doxycycline by swelling and its release was investigated in various media.

Selective fluorometric determination of sulfadiazine based on the growth of silver nanoparticles on graphene quantum dots.

A sensitive fluorometric assay is described for the direct determination of the antibiotic sulfadiazine. Silver nanoparticles placed on graphene quantum dots (Ag NP-GQDs) were synthesized by reduction of AgNO with sodium borohydride in the presence of GQDs. The growth of Ag NPs on the surface of the GQDs causes quenching of the blue fluorescence of the GQDs with an emission maximum at 470 nm by surface-enhanced energy transfer.

Surface molecularly imprinted polymer on magnetic multi-walled carbon nanotubes for selective recognition and preconcentration of metformin in biological fluids prior to its sensitive chemiluminescence determination: Central composite design optimization.

Novel molecularly imprinted polymer (MIP) for metformin was synthesized on the surface of magnetic multi-walled carbon nanotubes (MMWCNTs) as the support. Metformin was used as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2,2'-azoisobutyronitrile (AIBN) as the initiator. The synthesized composite was characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR).

Electron beam irradiation synthesis of porous and non-porous pectin based hydrogels for a tetracycline drug delivery system.

Electron beam irradiation was used for the synthesize of porous and non-porous pectin based hydrogels through conjugation of pectin with 5-hydroxytryptophan in the presence and absence of sodium dodecyl sulfate, respectively. The hydrogels were characterized by different methods. Tetracycline hydrochloride was loaded on the hydrogels by swelling equilibrium method and its release in different media was studied.

Non-enzymatic sensing of dopamine by localized surface plasmon resonance using carbon dots-functionalized gold nanoparticles.

A highly selective, sensitive, and rapid colorimetric sensor for the determination of dopamine (DA) was developed using the color change of S-doped carbon dots functionalized gold nanoparticles (S-CDs@Au NPs). The base of the method is the formation of a complex between the amine groups of dopamine with carboxylic groups of S-CDs@Au NPs followed by their aggregation with Fe ions which acts as the linkers causing a red shift from 520 to 670 nm in the localized surface plasmon peak of S-CDs@Au NPs. The ratio of absorbance intensity at 670 nm to 520 nm was monitored as the analytical signal for determination of dopamine.

A novel theranostic system of AS1411 aptamer-functionalized albumin nanoparticles loaded on iron oxide and gold nanoparticles for doxorubicin delivery.

Recently DNA aptamers have attracted remarkable attention as possible targeting ligands since selective targeting of cancer cells is a critical step in cancer diagnosis and therapy. Here, the development of AS1411 aptamer-functionalized albumin nanoparticles loaded on iron oxide and gold nanoparticles is reported for target delivery of the well-known anticancer drug of doxorubicin (Dox). Iron oxide nanoparticles (IONPs) and gold nanoparticles (GNPs) were prepared by ultrasound-assisted and controlled seeded growth synthetic methods, respectively.

Synthesis of composite hydrogel of glutamic acid, gum tragacanth, and anionic polyacrylamide by electron beam irradiation for uranium (VI) removal from aqueous samples: Equilibrium, kinetics, and thermodynamic studies.

A bio-compatible hydrogel sorbent was prepared through chemical conjugation of glutamic acid (GA) with gum tragacanth (GT) followed by mixing with anionic polyacrylamide (PAAm) and irradiating by the electron beam. The prepared composite of the hydrogel of GA-GT/PAAm was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, point zero charge (PZC) analysis, thermogravimetric analysis (TGA), and X-ray diffraction-(XRD). The sorption capability of the hydrogel was investigated for the removal of U(VI) from aqueous samples.

Simultaneous Functionalization and Reduction of Magnetic Graphene Oxide by L-Histidine and its Application for Magnetic Separation/Preconcentration of Antioxidant Trace Elements.

In the present study, for the first time, the magnetic graphene oxide was simultaneously functionalized and reduced with the aim of imidazole-based L-histidine amino acid (rGO/FeO-histidine). The prepared nanocomposite was characterized by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and vibrating sample magnetometer. The synthesized rGO/FeO-histidine nanosheets were implied for solid phase extraction of ultra-trace amounts of Zn, Cu and Mn from biological samples prior to ICP-OES determination.

Temperature-controlled liquid-liquid microextraction combined with high-performance liquid chromatography for the simultaneous determination of diazinon and fenitrothion in water and fruit juice samples.

A simple, environmentally benign, and rapid method based on temperature-controlled liquid-liquid microextraction using a deep eutectic solvent was developed for the simultaneous extraction/preconcentration of diazinon and fenitrothion. The method involved the addition of deep eutectic solvent to the aqueous sample followed by heating the mixture in a 75°C water bath until the solvent was completely dissolved in the aqueous phase. Then, the resultant solution was cooled in an ice bath and a cloudy solution was formed.

Modified dispersive liquid-phase microextraction based on sequential injection solidified floating organic drop combined with HPLC for the determination of phenobarbital and phenytoin.

A modified dispersive liquid phase microextraction based on sequential injection solidified floating organic drop was developed for simultaneous separation/preconcentration of trace amounts of phenobarbital and phenytoin. The important factors affecting on the extraction recovery including pH, the volume of extraction solvent, ionic strength, and the number of injections were investigated and optimized by Box-Behnken design and desirability function. Under the optimum experimental conditions, the calibration graph was linear in the concentration range of 1.

Synthesis, characterization, and application of a Zn (II)-imprinted polymer grafted on graphene oxide/magnetic chitosan nanocomposite for selective extraction of zinc ions from different food samples.

A novel Zn(II) imprinted polymer was synthesized via a co-precipitation method using graphene oxide/magnetic chitosan nanocomposite as supporting material. The synthesized imprinted polymer was characterized by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM) and applied as a sorbent for selective magnetic solid phase extraction of zinc followed by its determination by flame atomic absorption spectrometry. The kinetic and isothermal adsorption experiments were carried out and all parameters affecting the extraction process was optimized.

Indirect spectrophotometric determination of sulfadiazine based on localized surface plasmon resonance peak of silver nanoparticles after cloud point extraction.

A novel, efficient, easy to use, environmentally friendly and cost-effective methodology is developed for the indirect spectrophotometric determination of sulfadiazine in different samples. The method is based on the micelle-mediated extraction of silver sulfadiazine and converting the silver content of the resultant surfactant-rich phase to the silver nanoparticles via generation of [Ag(NH)] followed by its chemical reduction using ascorbic acid. The changes in the amplitude of localized surface plasmon resonance peak of silver nanoparticles as a function of sulfadiazine concentration in the sample solution was monitored using fiber optic linear array spectrophotometry at 457nm.

A novel sensor for determination of naproxen based on change in localized surface plasmon peak of functionalized gold nanoparticles.

A highly selective and sensitive colorimetric sensor for the determination of naproxen (NAP) based on the aggregation of the thiolated β-cyclodextrin (Tβ-CD) functionalized gold nanoparticles (Tβ-CD-Au NPs) in the presence of NAP and Znis described. The hydrophobic end of NAP interacts with the immobilized Tβ-CD on the Au NPs and forms the complex of Tβ-CD:NAP while the Zn ions form a 1:2 complex of (NAP)Zn with the carboxyl groups of NAP resulting in the aggregation of functionalized gold nanoparticles. As a result of aggregation, the localized surface plasmon resonance (LSPR) band of functionalized gold nanoparticles around 520nm decreases and a new red shifted band at 650nm appears which increases gradually as the function of NAP concentration.