Ultrasound-Assisted Emulsification Microextraction Based on Solidification Floating Organic Drop Trace Amounts of Manganese Prior to Graphite Furnace Atomic Absorption Spectrometry Determination

In the present study, an ultrasound-assisted emulsification microextraction based on solidification floating organic drop method is described for preconcentration of trace amounts of Mn (II). 2-(5-Bromo-2-pyridylazo)-5 diethylaminophenol was added to a solution of Mn+2 at ph = 10.0. After this, 1-undecanol was added to the solution as an extraction solvent, and solution was stirred. Several factors influencing the microextraction efficiency, such as pH, the amount of chelating agent, nature and volume of extraction solvent, the volume of sample solution, stirring rate, and extraction time were investigated and optimized. Then sample vial was cooled by inserting into an ice bath, and the solidified was transferred into a suitable vial for immediate melting. Finally the sample was injected into a graphite furnace atomic absorption spectrometry. Under the optimum condition the linear dynamic range was 0.50–10.0 ng mL−1 with a correlation coefficient of 0.9926, and the detection limit of 0.3 ng mL−1 was obtained. The enrichment factor was 160. The proposed method was successfully applied for separation and determination of manganese in sea, rain, tap, and river water samples

Determination of silver(I) by flame atomic absorption spectrometry after separation/preconcentration using modified magnetite nanoparticles

AbstractA new, simple, fast and reliable method has been developed for the separation/preconcentration of trace amounts of silver ions using 2-mercaptobenzothiazole/sodium dodecyl sulfate immobilized on alumina-coated magnetite nanoparticles (MBT/SDS-ACMNPs) and their determination by flame atomic absorption spectrometry (FAAS). Optimal experimental conditions, including pH, sample volume, eluent concentration and volume, and co-existing ions, have been studied and established. Under optimal experimental conditions, the enrichment factor, detection limit, linear range and relative standard deviation (RSD) of Ag(I) ions were 250 (for 500 mL of sample solution), 0.56 ng mL−1, 2.0–100.0 ng mL−1 and 3.1% (for 5.0 μg mL−1, n=10), respectively. The presented procedure was successfully applied for determination of silver content in the different samples of water

Dirac oscillator in an external magnetic field

We show that 2+1 dimensional Dirac oscillators in an external magnetic field is mapped onto the same with reduced angular frequency in absence of magnetic field. This can be used to study the atomic transitions in a radiation field. Relativistic Landau levels are constructed explicitly. Several interesting features of this system are discussed.Comment: Revised Version, Latex, 9 pages, No figs, To appear in Phys. Lett.

Noncommutative Dirac oscillator in an external magnetic field

We show that (2+1) dimensional noncommutative Dirac oscillator in an external magnetic field is mapped onto the same but with reduced angular frequency in absence of magnetic field. We construct the relativistic Landau levels by solving corresponding Dirac equation in (2+1) dimensional noncommutative phase space. We observe that lowest Landau levels are exactly same as in commutative space and independent of non-commutative parameter. All the Landau levels become independent of noncommutative parameter for a critical value of the magnetic field. Several other interesting features along with the relevance of such models in the study of atomic transitions in a radiation field have been discussed.Comment: 10 pages, Np figs, communicated to journal. arXiv admin note: text overlap with arXiv:0907.454

Novel membrane-based electrochemical sensor for real-time bio-applications.

This article presents a novel membrane-based sensor for real-time electrochemical investigations of cellular- or tissue cultures. The membrane sensor enables recording of electrical signals from a cell culture without any signal dilution, thus avoiding loss of sensitivity. Moreover, the porosity of the membrane provides optimal culturing conditions similar to existing culturing techniques allowing more efficient nutrient uptake and molecule release. The patterned sensor electrodes were fabricated on a porous membrane by electron-beam evaporation. The electrochemical performance of the membrane electrodes was characterized by cyclic voltammetry and chronoamperometry, and the detection of synthetic dopamine was demonstrated down to a concentration of 3.1 pM. Furthermore, to present the membrane-sensor functionality the dopamine release from cultured PC12 cells was successfully measured. The PC12 cells culturing experiments showed that the membrane-sensor was suitable as a cell culturing substrate for bio-applications. Real-time measurements of dopamine exocytosis in cell cultures were performed, where the transmitter release was recorded at the point of release. The developed membrane-sensor provides a new functionality to the standard culturing methods, enabling sensitive continuous in vitro monitoring and closely mimicking the in vivo conditions

Properties and customization of sensor materials for biomedical applications.

Low-power chemo- and biosensing devices capable of monitoring clinically important parameters in real time represent a great challenge in the analytical field as the issue of sensor calibration pertaining to keeping the response within an accurate calibration domain is particularly significant (1–4). Diagnostics, personal health, and related costs will also benefit from the introduction of sensors technology (5–7). In addition, with the introduction of Registration, Evaluation, Authorization, and Restriction of Chemical Substances (REACH) regulation, unraveling the cause–effect relationships in epidemiology studies will be of outmost importance to help establish reliable environmental policies aimed at protecting the health of individuals and communities (8–10). For instance, the effect of low concentration of toxic elements is seldom investigated as physicians do not have means to access the data (11)

One-step ultrasonic production of the chitosan/lactose/g-C3N4 nanocomposites with lactose as a biological capping agent: Photocatalytic activity study

In this work, the basic and applied purpose was to synthesize and modify chitosan/lactose nanocomposites with g-C3N4 structures using the ultrasonic-assisted electrospinning method. We evaluated effective photocatalytic of chitosan/lactose/g-C3N4 nanocomposites to photodegrade methyl red, methyl orange, and methyl blue in different nanophotocatalyst concentration such as 0.1�1g/L in pH 6.5. According to the experimental results, it was found that nanocomposites in different concentrations of g-C3N4 had high potential in degradation of organic compounds. The lactose structures as a green capping agent and stabilizer modified chitosan surfaces to produce uniform particle size distribution. Different lactose concentrations like 0.1�0.5wt/vol indicate a particle size range between 270 and 422 nm. The obtained as-synthesized nanomaterials were characterized by scanning electron microscope, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and UV�Vis spectroscopy. The crystalline size and diameter (Dc) of the nanostructures can be determined through XRD data with �90�110 nm. Results show that photocatalytic activity in low pH is more increased than other values due to more electron�hole pairs formed on the surface. © 2021 The Chemical Society Located in Taipei & Wiley-VCH Gmb

Determination of ciprofloxacin drug with molecularly imprinted polymer/co- metal organic framework nanofiber on modified glassy carbon electrode (GCE)

In this paper, we report the Co-metal organic frameworks (MOFs) were successfully synthesized with the aid of 2,6-pyridinedicarboxylic acid ammonium as an organic ligand in polylactic acid (PLA) as a biodegradable and biocompatibility polymer substrate through the ultrasonic-assisted electrospinning method. Co-MOFs/PLA nanofiber used as a new nanocomposite for design and construction of nanosensor based on the polymer prepared of the 4-aminobenzoic acid electrolytic molecule for measuring ciprofloxacin (CIP) drug class. The molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) sensors were studied by differential pulse voltammetry (DPV) to study changes in oxidation peaks and reduction of potassium ferricyanide. The calibration curve for ciprofloxacin was in the range of 0.5�150 μM also the detection limit was 0.017 μM and the standard deviation for five consecutive measurements at 60 μM concentration was calculated1.7 respectively. For characterizing the synthesized Co-MOF/PLA nanofiber we used X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDAX), Transmission electron microscopy (TEM) and Dynamic light scattering (DLS). In this study, we present new nanosensors with Co-MOF/PLA nanofiber as a biodegradable and bioactive composite for the first time in modified carbon paste electrode using the ultrasound-assisted direct micelle (UADM) method as the determination of ciprofloxacin drug. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature