Magnetic molecularly imprinted polymer nanoparticles for the solid-phase extraction of paracetamol from plasma samples,followed its determination by HPLC

We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were prepared from magnetite (Fe₃O₄) as the magnetic component, paracetamol as the template, methacrylic acid as a functional monomer, and 2-(methacrylamido) ethyl methacrylate as a cross-linker. The m-MIPs were then characterized by transmission electron microscopy, FT-IR spectroscopy, X-ray diffraction and vibrating sample magnetometry. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples. Following its elution from the column loaded with the m-MIPs with an acetonitrile-buffer (9:1) mixture, it was submitted to HPLC analysis. Paracetamol can be quantified by this method in the 1 μg L⁻¹ to 300 μg L⁻¹ concentration range. The limit of detection and limit of quantification in plasma samples are 0.17 and 0.4 μg L⁻¹. The preconcentration factor of the m-MIPs is 40. The HPLC method shows good precision (4.5 % at 50 μg L⁻¹ levels) and recoveries (between 83 and 91 %) from spiked plasma samples.

We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples

     

Magnetic Nanoparticles Supported Ionic Liquids Improve Firefly Luciferase Properties

Ionic liquids as neoteric solvents, microwave irradiation, and alternative energy source are becoming as a solvent for many enzymatic reactions. We recently showed that the incubation of firefly luciferase from Photinus pyralis with various ionic liquids increased the activity and stability of luciferase. Magnetic nanoparticles supported ionic liquids have been obtained by covalent bonding of ionic liquids-silane on magnetic silica nanoparticles. In the present study, the effects of [γ-Fe₂O₃@SiO₂][BMImCl] and [γ-Fe₂O₃@SiO₂][BMImI] were investigated on the structural properties and function of luciferase using circular dichroism, fluorescence spectroscopy, and bioluminescence assay. Enzyme activity and structural stability increased in the presence of magnetic nanoparticles supported ionic liquids. Furthermore, the effect of ingredients which were used was not considerable on K _m value of luciferase for adenosine-5′-triphosphate and also K _m value for luciferin.     

Analytical Nusselt number for forced convection inside a porous-filled tube with temperature-dependent thermal conductivity arising from high-temperature applications

Journal of Thermal Analysis and Calorimetry - The convection heat transfer inside a tube filled with a porous material under the constant heat flux thermal boundary condition which is widely used...     

Second law analysis for nanofluid flow in mini-channel heat sink with finned surface: a study on fin geometries

Journal of Thermal Analysis and Calorimetry - In this numerical work, a second law analysis is carried out for the nanofluid flow and heat transfer in the mini-channel with finned surface. The...     

Efficient polymeric catalyst for one-pot synthesis of acenaphtho[1,2-b]pyrroles

Some new derivatives of acenaphtho[1,2-b]furans have been synthesized efficiently by one-pot reaction of (acenaphthylen-1-yloxy)trimethylsilane, various aldehydes, and isocyanides in the presence of silica-supported ionic liquid.     

Application of a magnetic molecularly imprinted polymer for the selective extraction and trace detection of lamotrigine in urine and plasma samples

Magnetic molecularly imprinted polymers have been synthesized for the selective preconcentration and trace determination of lamotrigine (LTG) in urine and plasma samples. The magnetic nanoparticles were modified by tetraethyl orthosilicate and 3‐methacryloxypropyl trimethoxysilane before imprinting. The magnetic molecularly imprinted polymers were prepared via surface molecular imprinting technique, using Fe₃O₄ as a magnetic component, LTG as template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross‐linker, and 2,2′‐azobisisobutyronitrile as a radical initiator in methanol/acetonitrile (50:50, v/v) as the porogen. The obtained sorbent was characterized using scanning electron microscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction, and thermal analysis. Separation of the sorbent from the sample solution was simply achieved by applying an external magnetic field. Determination of the extracted drug was performed by high‐performance liquid chromatography with UV detection. Under the optimum extraction conditions, the method detection limits were 0.7 μg/L (based on S/N of 3) for urine samples and 0.5 μg/L for plasma samples. A linear dynamic range of 1–1000 μg/L was obtained for LTF in plasma and urine samples. Finally, the applicability of the proposed method was evaluated by extraction and determination of LTG in urine and plasma samples.     

The exploration of interaction studies of smaller size, mostly ignored yet intrinsically inestimable molecules towards BSA; An example of STD and DOSY NMR

Larger size or novel structure molecules are always appreciated by all fields of experimental and computational science. Conversely, molecules with smaller size and simple structures are usually ignored with no explanation as to why. However, the vast majority of more diminutive molecules behave as a cornerstone in the synthesis of a bigger structural framework. Subsequently, we planned to uncover the interactions of small molecules towards macromolecules, and successfully presented the binding results of 2-aminopyridine and Isovanillin towards BSA through NMR techniques. STD epitope mapping and also the DOSY results provided evidence that Isovanillin remained closer to the binding cavity of protein. Titration experiments afforded 584 µM (0.584mM) and 487 µM (0.487 mM) dissociation constants for isovanillin and 2-aminopyridine respectively. Furthermore, changes in diffusion coefficient (with and without protein addition in DOSY spectra) were found to be 0.081 log (m² s^?1) and 0.096 log (m² s^?1) points for isovanillin and 2-aminopyridine respectively. Docking studies exhibit that these molecules can tie to site 1 (sub-area IIA) through the pi-pi interaction and hydrogen bonding with Trp213. Our results demonstrated that both compounds could be utilized as part of a transporter in the circulatory system and their extension-inspired compounds may be utilized in new drug design.      

Chromatographic Behavior of Aromatic Diamines in Hydro-Organic, Micellar and Submicellar Reversed Phase Liquid Chromatographic Modes

The chromatographic behavior (retention, elution strength, efficiency, peak asymmetry and selectivity) of some aromatic diamines in the presence of methanol with or without anionic surfactant SDS in the four different reversed phased liquid chromatographic (RPLC) modes, i.e., hydro-organic, micellar (MLC), low submicellar (LSC) and high submicellar (HSC), was investigated. In the three surfactant-mediated modes, the surfactant monomers coat the stationary phase even up to 70 % methanol; this results in the suppression of peak tailing (by masking the silanol groups on the stationary phase). In MLC and HSC, the solute retention decreases by increasing the surfactant concentration, while this situation was reversed in LSC. In the region between MLC and HSC modes (25–50 % methanol), retention of late eluting solutes was increased by increasing methanol content which is seemingly due to disaggregation of SDS micelles. Changes in selectivity were observed after changing the concentrations of SDS and methanol, in a greater extent when concentration of SDS was changed. Among the four studied RPLC modes, HSC showed the best efficiency with nearly symmetrical peaks. Prediction of retention of solutes in HSC based on a mechanistic retention model combined with Pareto-optimality method allowed the full resolution of target diamines in practical analysis times.     

Fundamental and subphenomena of boiling heat transfer

Journal of Thermal Analysis and Calorimetry - Boiling process can be widely used in different industrial applications. In this two-phase heat transfer, the latent heat of vaporization of a liquid...     

Heat transfer intensification in microchannel by induced-charge electrokinetic phenomenon: a numerical study

Journal of Thermal Analysis and Calorimetry - In this numerical investigation, the induced-charge electrokinetic phenomenon is used to intensify the convective heat transfer rate in the...