Browsing by Author "Alma, Mehmet Hakki"

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Nanotube-Boramidic Acid Derivative for Dopamine Sensing
(Wiley-v C H verlag Gmbh, 2021) Yigit, Aybek; Pinar, Pinar Talay; Akinay, Yuksel; Alma, Mehmet Hakki; Menges, Nurettin
A new sensor, based on boramidic acid-bounded MWCNTs (Multi-walled carbon nanotubes), was synthesized in three simple steps. Modification of the sensor surface was accomplished using boric acid in which the boron atom is adjacent to the NH group. Characterization, electrochemical behaviors, and stability of newly modified nanosensor were completed using SEM (scanning electron microscope), TEM (Transmission electron microscope), CV (cyclic voltammetry), EIS (electron impedance), DTA (Differential thermal analysis), and XPS (X-ray photoelectron spectroscopy). SEM and TEM analysis were confirmed the modified surface of the nanosensor. The stability of the newly synthesized sensor was also designated that the initial weight loss occurred between 50-145 degrees C was corresponded to the degradation of both ethylene diamine and boric acid. According to the EIS study, the Nyquist plot of the MWCNTs-NH-B (OH)(2)/GC electrode displayed a 0.435 k omega Rct with a smaller semicircle than the bare GC (6.57 k omega). The electrochemical behavior of dopamine was investigated using cyclic and square wave voltammetry (0.1 M phosphate buffer solution-pH 7.4). The diffusion-controlled process was determined when the oxidation of dopamine was studied. The detection limit of dopamine was found to be 5.1 nM. An actual sample study was done using the developed analytical method, and the detection of dopamine in urine was successfully performed. This study is the first example of boramidic acid-modified multi-walled carbon nanotubes
Pdruo2/Pvp Nanomaterial as a Highly Selective, Stable, and Applicable Potentiometric Sensor for the Detection of Cr3+
(Springer Wien, 2024) Cevik, Kenan; Yildiz, Ilyas; Yildiz, Adnan; Nas, Mehmet Salih; Alma, Mehmet Hakki; Calimli, Mehmet Harbi
PdRuO2/PVP nanomaterial was synthesized using a straightforward method and characterized using advanced analytical methods such as TEM, XRD, XPS, elemental mapping and SEM. The synthesized PdRuO2/PVP nanomaterial was used as an ionophore in potentiometric sensor electrodes and successfully adapted to Cr3+ ion detection in a large number of aqueous samples. Several experimental parameters of the PdRuO2/PVP sensor such as potentiometric behavior, selectivity, repeatability, response time, pH, titration, and recovery in real samples were investigated. Potentiometric behavioral characteristics were performed in the concentration range 1 x 10(-6)-1.0 x 10(-1) M. The repeated experiments performed six times showed that there was no deviation in the measurements. The limit of detection of the PdRuO2/PVP potentiometric sensor was very low with a value of 8.6 x 10(-8) M. The potentiometric measurements showed that the synthesized PdRuO2/PVP ionophore was highly effective in detecting Cr3+ in a wide pH range of 2.0-8.0 and was found to have a shelf life of over 1 year. As a result, the synthesized PdRuO2/PVP electrode material was found to be highly selective, stable, and applicable for Cr3+ detection.
What Is the Eco-Toxicological Level and Effects of Graphene Oxide-Boramidic Acid (go-Ed Np) ?: in Vivo Study on Zebrafish Embryo/Larvae
(Elsevier Sci Ltd, 2022) Kokturk, Mine; Yildirim, Serkan; Yigit, Aybek; Ozhan, Gunes; Bolat, Ismail; Alma, Mehmet Hakki; Atamanalp, Muhammed
Graphene oxide (GO) and their natural/synthetic composites are encouraging tools for humanity. There is a need to address critical challenges and potential risk possibilities in GO-based architectures, which have a wide range of uses. In this study, ecotoxicological levels as well as GO-based nanoparticle synthesis, characterization, interaction mechanism and toxicity detection levels for potential biomedical applications were determined on zebrafish (Danio rerio). The effects of GO-ED-BA NP (graphene oxide-boramidic acid nano particles) which was characterized by FT-IR, SEM, TEM, and BET on survival rate, morphological abnormalities (yolk sac edema, lordosis/kyphosis, pericardial edema, and tail malformation), hatching rate as well as neuronal degeneration /necrosis, 8 OHdG and TNF-alpha expression were observed in D. rerio embryos and larvae. In the obtained findings, it was determined that the toxicity profile of GO-ED-BA NP appeared similar, in high-dose application with single GO use, causing a cytotoxic, pro-inflammatory response and triggering oxidative stress. However, increased malformation rates and mortality at the highest concentration were due to nanoparticle sizes and GO. The presence of boramidic acid unit on graphene nanostructure changed the GO's toxicity profile and positively directed the proinflammatory and oxidative stress response. Synthesizing of graphene oxide-boramidic acid and its toxicity panels compared to graphene oxide are reported for the first time in this study.