Ultrasound assisted dispersive micro solid-phase extraction of four tyrosine kinase inhibitors from serum and cerebrospinal fluid by using magnetic nanoparticles coated with nickel-doped silica as an adsorbent

Nanoparticles (NPs) consisting of a magnetic Fe₃O₄ core and a nickel(II)-doped silica shell were prepared and are shown to be viable materials for selective magnetic extraction of trace quantities of the tyrosine kinase inhibitors (TKIs) imatinib, nilotinib, erlotinib and sunitinib. The NPs were characterized by scanning electron microscopy, transmission electron microscopy, DLS and XRD analysis, and the results revealed a uniform in size (with a typical diameter of 40 nm) and a core-shell structure. The magnetic nanoadsorbent displays good affinity of the TKIs, probably because of the affinity between the Ni(II) ions of the NPs with the nitrogen atoms in the TKIs. The magnetism of the NPs enables them to be quickly separated from serum and cerebrospinal fluid samples. Imidazole, with its higher affinity for Ni(II) than that of the TKIs, was used for desorption of the TKIs from the NPs prior to their quantification by HPLC with UV detection. The detection limits are as low as 200, 480, 130, and 250 ng·L￣¹ for imatinib, sunitinib, erlotinib, and nilotinib, respectively. The intra-day precisions (RSDs) were lower than 4.0 %. The method displays a wide linear range. It was applied to the determination of TKIs in (spiked) human serum and cerebrospinal fluid and gave recoveries in the range from 94.6 to 98.6 %.     

Headspace solid-phase microextraction of menthol using a sol–gel titania-based coating along with multiwalled carbon nanotubes on the surface of stainless steel fiber

Sol–gel coating technology for the preparation of solid-phase microextraction fibers involves a single-step procedure and allows for in situ creation of chemically bonded coatings which are characterized by high thermal and solvent stabilities. A novel titania sol–gel coating was prepared for the first time on a stainless steel fiber and applied for the headspace solid-phase microextraction (HS-SPME) of menthol with gas chromatography and flame ionization detection. Important parameters influencing the efficiency of SPME process, such as extraction time, extraction temperature and ionic strength, were optimized by central composite design. An extraction time of 40 min at 60 °C gave maximum extraction efficiency, when NaCl (10% w/v) was added to the aqueous sample. The analytical characteristics of the proposed method were comparable with other reported fibers. Under optimized conditions, the linearity was between 0.05 and 100 µg mL^??1. The relative standard deviations (RSDs) determined at 0.5 µg mL^??1 concentration level (n?=?5) were as follows: intra-day RSD 7.26%; inter-day RSD 10.87%; fiber-to-fiber RSD 9.05%. The relative recoveries determined after spiking a mint distillate sample at three concentration levels from 0.067 to 50.0 µg mL^??1 varied from 86 to 102%. The proposed method was successfully applied for the analysis of menthol in peppermint samples.     

Synthesis and crystal structure determination of copper(II) and iron(III) complexes of 2-(2-pyridyl)benzothiazole

Two complexes [Cu^II(pbt)(dmf)Cl₂] and [Fe^III(pbt)Cl₃], where pbt is 2-(2-pyridyl)benzothiazole, and dmf is dimethylformamide, were prepared by the reaction of metal chlorides with pbt solutions. The structures of the products were identified by elemental analysis, usual spectroscopic methods and X-ray diffraction analysis. The crystal data revealed penta-coordination around both metal ions, with trigonal bipyramidal geometries. 2-(2-pyridyl)benzothiazole binds to both Cu^II and Fe^III in the N,N-chelation manner and leaves the S atom uncoordinated.     

Development of a novel hybrid SOFC/GT system and transcritical CO2 cycle for CCHP purpose in the district scale

Journal of Thermal Analysis and Calorimetry - The main target of this work is to optimize a novel hybrid system which includes solid oxide fuel cell, gas turbine, and transcritical CO2 power cycle....     

Cu2O nanocrystals with various morphology: Synthesis,characterization and catalytic properties

Cu₂O nanocubes, octahedra, spheres and truncated rhombic dodecahedral were prepared and their structural, morphological, and electronic properties were investigated by X-ray diffraction analysis, X-ray absorption near edge structure, scanning electron microscope and transmission electron microscope and X-ray absorption near edge structure. Cu₂O nanocrystals were successfully employed to catalyze the 1,3-dipolar cycloaddition reaction for the synthesis of 1,4-disubstituted triazoles. Cu₂O nanocubes and octahedral showed the superior catalytic performance in the cycloaddition reaction. These results reveal that crystal-plane engineering of oxide catalysts is a useful strategy for developing efficient catalysts for organic reaction.     

Electrochemical characterization of naproxen and the adsorbed naproxen oxidation products at glassy carbon electrode modified with carboxyl functionalized multi-walled carbon nanotubes and introducing a new route for naproxen determination

Journal of Solid State Electrochemistry - In the present work, a glassy carbon electrode was modified with carboxyl functionalized multi-walled carbon nanotubes (f-MWCNTs) to investigate the...     

Synthesis and application of a novel magnetic SBA-15 nanosorbent for heavy metal removal from aqueous solutions

Journal of Sol-Gel Science and Technology - In this work for the first time, magnetic nanoporous SBA-15 functionalized with isatin groups as a magnetic nanosorbent was applied for the simultaneous...     

A Comprehensive Review of Aminochalcones

Chalcones, members of the flavonoid family, display a plethora of interesting biological activities including but not limited to antioxidant, anticancer, antimicrobial, anti-inflammatory, and antiprotozoal activities. The literature cites the synthesis and activity of a range of natural, semisynthetic, and synthetic chalcones. The current review comprehensively covers the literature on amino-substituted chalcones and includes chalcones with amino-groups at various positions on the aromatic rings as well as those with amino-groups containing mono alkylation, dialkylation, alkenylation, acylation, and sulfonylation. The aminochalcones are categorized according to their structure, and the corresponding biological activities are discussed as well. Some compounds showed high potency against cancer cells, microbes, and malaria, whereas others did not. The purpose of this review is to serve as a one-stop location for information on the aminochalcones reported in the literature in recent years.     

The Catalytic Reduction of Nitroanilines Using Synthesized CuFe2O4 Nanoparticles in an Aqueous Medium

The primary objective of this research is to investigate the reduction of 4‐nitroaniline (4‐NA) and 2‐nitroaniline (2‐NA) using synthesized copper ferrite nanoparticles (NPs) via facile one‐step hydrothermal method as a heterogeneous nano‐catalyst. Nitroanilines were reduced in the presence and without the catalyst with a constant amount (100 mg) of reducing agent of sodium borohydride (NaBH₄) at room temperature in water to amino compounds. To characterize the functional groups, size, structure, and morphology of as‐prepared magnetic NPs, FTIR, XRD, SEM, and TEM were employed. The UV‐Vis spectrum was utilized to explore the catalytic effect of CuFe₂O₄. The outcomes revealed that the synthesized CuFe₂O₄ as a heterogeneous magnetic nano‐catalyst catalyzed the reduction of 4‐NA and 2‐NA significantly faster than other candidate catalysts. The outcomes demonstrated that the catalyst catalyzed 4‐nitroaniline to para‐phenylenediamine (p‐PDA) and 2‐nitroaniline to ortho‐phenylenediamine (o‐PDA) with a constant rate of 7.49×10⁻² s⁻¹ and 3.19×10⁻² s⁻¹, and conversion percentage of 96.5 and 95.6, in 40 s and 90 s, sequentially. Furthermore, the nanoparticles could be recovered by a magnetic separation method and reused for six consecutive cycles without remarkable loss of catalytic ability.     

Flow injection spectrophotometric determination of trace amounts of selenium

A simple, rapid and sensitive flow injection spectrophotometric method for determination of selenium (0.005-1.5 mug ml(-1)) is described. The method is based on the catalytic effect of Se(IV) on the reduction reaction of thionine (TN) with sulphide ion, monitored spectrophotometrically at 598 nm. The detection limit is 5 ng ml(-1) the relative standard deviation for eight replicate measurements is 1.1% for 1 mug ml(-1) of selenium. The sampling rate is 25-30 samples h(-1). The procedure was applied successfully to the determination of selenium in real samples.