Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ3Sensitive Electrochemical Analysis of Gentamicin Sulfate in Eye Solution
Ekşi, Osman; İpek, Yeliz; Koçak, Berna
In this study, for the first time, chromium (III) oxide-glutardialdehyde modified boron-doped diamond electrode (Cr2O3-GA2/BDDE) was used as a sensor for the electrochemical analysis of gentamicin sulfate. The Cr2O3-GA2 suspension used in electrode modification was physically coated on the BDD electrode by a simple drop-casting method. Characterization of Cr2O3-GA2 used in the modification was made by scanning electron microscopy, energy-dispersive spectroscopy (SEM-EDS), and the electrochemical method. The behavior of gentamicin sulfate on Cr2O3-GA2/BDDE was studied by cyclic voltammetry (CV), and its electrochemical analysis was done by differential pulse voltammetry (DPV). Electrochemical analysis of gentamicin sulfate on Cr2O3-GA2/BDDE was carried out in a pH 9 Britton–Robinson (BR) buffer by the DPV method. The linear working range of gentamicin sulfate on Cr2O3-GA2/BDDE was calculated as 5.96 × 10−6−6.54 × 10−5mol L−1, and the correlation coefficient was calculated as 0.997. The limit of detection (LOD) was found to be 2.84 × 10−6. mol L−1. Additionally, Genta, a 3% eye/ear drop solution, was preferred to determine the applicability of gentamicin sulfate in a commercial formulation. As a result, it was shown that the method developed on Cr2O3-GA2/BDDE for the determination of gentamicin sulfate can be applied to commercial drugs.
- MakaleAçık Erişim2026Scopus SJRQ2Electrochemical analysis of tetracycline in drug formulations with glutardialdehyde-Fe2O3 modified glassy carbon electrode
Koçak, Berna; İpek, Yeliz
In this study, a glutardialdehyde-Fe2O3 modified glassy carbon electrode (GA2–Fe2O3/GCE) was used as a sensor for the electrochemical analysis of tetracycline (TC) in drug formulations. The electrochemical behavior of TC on GA2-Fe2O3/GCE was investigated using cyclic voltammetry (CV), while the quantitative determination was performed via differential pulse voltammetry (DPV). After optimizing the experimental conditions, the linear working range, limit of (LOD) detection, and limit of quantification (LOQ) of the GA2-Fe2O3/GCE electrode developed for the electrochemical analysis of TC were found to be 1.0 × 10−6–2.0 × 10−5 M and 2.0 × 10−5–9.9 × 10−6 M; 4.78 × 10−7 M; 1.59 × 10−6 M, respectively. In the sensor application study conducted on a Tetra® Gensenta tablet to demonstrate the applicability of the developed method, the linear working range, LOD, and LOQ values of the sensor were found to be 1.0 × 10−6–14.8 × 10−5 M; 5.72 × 10−7 M and 1.74 × 10−6 M, respectively. The applicability of the method was demonstrated through tablet recovery studies, and the tablet recovery ratio was determined to be 100.94%.
- MakaleYalnız künye2026Scopus SJRQ2Synthesis of Aminothiophene derivative complexes and electrochemical sensor application for carbofuran pesticide
Taş, Abdurrahim; İpek, Yeliz; Adiguzel, Ragip
In this study, a ligand named 2-amino-6-ethyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3‑carbonitrile (ATL), which is an aminothiophene ligand, was synthesized. ATL was used to synthesize ATL-Co(II), ATL-Cu(II), and ATL-Zn(II) complexes. The chemical structures of the complexes were elucidated by spectroscopic methods such as FT-IR, UV–visible, and LC-MS analysis, as well as TG-DTA analysis, magnetic susceptibility measurements, and elemental analysis. Finally, the electrochemical characterization of ATL and the electrochemical sensor application of its complexes was performed. In electrochemical sensor studies, a carbofuran pesticide sensor application was investigated. ATL exhibited an irreversible oxidation peak around 1.0 V. It was observed that ATL-Co(II), ATL-Cu(II), and ATL-Zn(II) complexes behaved similarly to ATL and exhibited an irreversible oxidation peak at the same potential. Carbofuran pesticide was added to the sensor medium using the standard addition method. The changes in peak current with different carbofuran concentrations constituted the data of the amperometric sensor application, and the changes in the peak potential constituted the data of the voltammetric sensor application. Linear working ranges, LOD, and LOQ values were calculated for ATL, ATL-Co(II), ATL-Cu(II), and ATL-Zn(II) complexes, separately. The widest operating range as a voltammetric sensor was achieved with the ATL: 20 μmol L−1 to 350 μmol L−1. The lowest LOD and LOQ values were achieved with the ATL-Co(II) complex for voltammetric detection as 8.8 μmol L−1 and 29.2 μmol L−1, respectively. The lowest LOD and LOQ values were achieved with the ATL-Co(II) complex as 1.6 μmol L−1 and 5.2 μmol L−1 with the amperometric technique, respectively.
- MakaleYalnız künye2025Scopus SJRQ2Evaluation of Nano-Zinc Borate Effects on Thermal Properties, Morphology, Antibacterial Activity, and Drug Release Behavior of Starch/Gelatin Hydrogel Films for Biomedical Applications
Koçak, Berna; Gürler, Nedim; İpek, Yeliz; Yazdıç, Ferit Can; Karaman, Altuğ
Starch and gelatin offer opportunities for use due to their non-toxicity, biocompatibility, physical and functional properties. In this study, different amounts of nano-zinc borate were added to starch/gelatin composition for biological applications and their properties were studied. The structure of the films was investigated by various techniques. Nanostructured zinc borate was synthesized using a chemical method and particle sizes were determined as 196 nm. The atenolol drug was doped into the polymer composite. The atenolol release was performed at pH 7.4 and in phosphate-buffered saline solution medium. Cumulative drug release was 76% with the inclusion of nano-zinc borate in the polymer mixture. The atenolol release was approximately 50%–70% in films with nano-zinc borate added after 300 min. Furthermore, thermal resistance of the films improved with the addition of nano-zinc borate. The investigated chemical compound exhibited pronounced antibacterial activity against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), with significantly greater potency compared to Gram-negative bacteria (E. coli and Pseudomonas aeruginosa). Notably, the formulation containing 1.5% starch, 0.5% gelatin, and 1% nano-zinc borate demonstrated broad-spectrum efficacy against all tested pathogens, highlighting its potential as a promising antibacterial agent. The observed differential activity against bacterial strains suggests that fine-tuning the concentrations of starch, gelatin, and nano-zinc borate may optimize antibacterial efficacy and broaden the spectrum. The results showed us that non-toxic and biocompatible polymer films can be realized in pharmaceutical industry systems and biomedical applications.
- MakaleYalnız künye2025Scopus SJRQ2Highly sensitive DNA-based electrochemical biosensor for analysis of oseltamivir used in treatment of COVID–19
Keçeci, Ali; Koçak, Berna; İpek, Yeliz
Promising clinical results were obtained in the treatment of coronavirus disease by using favipiravir, umifenovir, remdesivir, ribavirin, lopinavir–ritonavir, oseltamivir, etc., antiviral drug active agents. In this study, quantitative analysis of oseltamivir neuraminidase inhibitor was carried out using electrochemical techniques. DNA-based electrochemical biosensors are generally used for analysis of anticancer and antitumor medicines. The present study introduces a novel DNA-based electrochemical sensor for neuraminidase inhibitor drug oseltamivir. The developed sensor enables the analysis of oseltamivir in a more environmentally friendly, more economical and faster way. It can be used in quality control laboratories in tablet production and will provide traceability of the drug in drug development studies and analysis in urine samples. For this purpose, a modified glassy carbon electrode was used as a working electrode. The glassy carbon electrodes alone cannot detect the oseltamivir. Guanine base, which was determined to interact with oseltamivir and found in the deoxyribonucleic acid structure, was used as an electrochemical biosensor agent. The guanine base was immobilized on glassy carbon electrode using glutardialdehyde as a crosslinker material and GA2–Guanine/GCE electrode was achieved. Two working ranges were determined for the Britton-Robinson buffer solution, tablet sample, and urine sample containing oseltamivir. The lowest detection limits (LODs) were calculated as 7.16 × 10−9 mol L−1, 9.05 × 10−9 mol L−1 and 6.19 × 10−6 mol L−1 for Britton-Robinson buffer solution, tablet sample solution, and urine sample solution, respectively. The recovery ratio for the proposed sensor ranged between 86.6 and 103.5%.
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İncele - MakaleYalnız künye2025Scopus SJRQ3Cotton Fabric and Polypropylene Fabrics Treated with Synthesized Zinc Diborate
İpek, Yeliz; Ertekin, Özlem
Cotton fabrics and polypropylene fabrics are mostly used fabrics in many areas. Zn(B4O7) powder was synthesized with a sequential wet precipitation and sintering method. Focused ion beam scanning electron microscopy (FIB-SEM) figures and energy dispersive X-ray spectroscopy (EDS) mapping results showed that zinc diborate was highly and homogeneously adsorbed on the surface of the treated fabrics. When differential thermal analysis (DTA) results were examined, heat release seemed to decrease by 0.71 kJ g−1, 0.61 kJ g−1, and 0.46 kJ g−1for cotton fabric treated with zinc diborate (C-117-ZB), polypropylene fabric (20 g m−2) treated with zinc diborate (PP-20-ZB), and polypropylene fabric (65 g m−2) treated with zinc diborate (PP-65-ZB), respectively. According to vertical burning test, burning rates of cotton fabric (C‒117), C‒117‒ZB, polypropylene fabric (PP‒65), PP‒65‒ZB, polypropylene fabric (PP‒20), and PP‒20‒ZB were calculated as 3.25 cm s−1, 1.93 cm s−1, 0.75 cm s−1, 0.36 cm s−1, 0.88 cm s−1, and 0.71 cm s−1, respectively. Heat releases and burning rate decreases were in good agreement for all treated fabrics. Also breaking strengths of both fabric types were improved. The washing test exhibited that the amount of zinc diborate powder on the cotton fabric sample was released by 25.49% while PP-65-ZB and PP-20-ZB fabrics released about 90% by weight of adsorbed powder. Although improvement was observed in the fire resistance of PP fabrics, antibacterial activity against Escherichia coli and Staphylococcus aureus could not be achieved. However, antibacterial activity was provided only for the cotton fabric.
- MakaleYalnız künye2023Scopus SJRQ3Nafion–Titanium (IV) Oxide-Graphene Modified Glassy Carbon Electrode (GCE) Based Electrochemical Sensor for the Voltammetric Determination of the β-blocker Bisoprolol Fumarate
Koçak, Berna; İpek, Yeliz
A Nafion–titanium (IV) oxide-graphene modified glassy carbon electrode (n-TiO2-GR/GCE) was used for the electrochemical determination of bisoprolol fumarate (BF). The modified electrode was prepared by depositing Nafion–titanium (IV) oxide-graphene onto the glassy carbon electrode by simple drop-casting. Differential pulse voltammetry (DPV) and square wave voltammetry (SWV) were used in the electrochemical determination of bisoprolol fumarate. The linear working range of bisoprolol fumarate for n-TiO2-GR/GCE DPV was from 3.0 × 10−7 to 5.0 × 10−6mol L−1 and the detection limit was 1.01 × 10−7mol L−1. In addition, with this developed method, the determination of bisoprolol fumarate in tablets was successfully performed with a recovery of 98.65%.
AtıfScopus3WoS2OpenAlex3İncele - MakaleYalnız künye2023Scopus SJRQ2A novel electrochemical sensor for metoprolol analysis based on glutardialdehyde–zinc oxide modified boron doped diamond electrode
Koçak, Berna; İpek, Yeliz; Keçeci, Ali
In this study, glutardialdehyde–zinc oxide modified boron doped diamond electrode (GA2–ZnO/BDDE) was developed as a new electrochemical sensor for the rapid, sensitive and selective determination of metoprolol (MTP). By using boron doped diamond electrode (BDDE), glutardialdehyde modified boron doped diamond electrode (GA2/BDDE) and glutardialdehyde–zinc oxide modified boron doped diamond electrode (GA2–ZnO/BDDE) separately, the electrochemical behavior of MTP on the surfaces of these electrodes was determined by applying cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. According to the results, the linear working range was 9.99 × 10−7–3.85 × 10−5 mol·L−1 and the limit of detection (LOD) was 7.53 × 10−8 mol·L−1 in pH 7 Britton–Robinson buffer solution. In addition, intraday reproducibility of peak current and peak potential were measured on the GA2–ZnO/BDDE surface and the results were calculated as 0.56 and 1 (RSD%), respectively. In order to investigate the reproducibility of GA2–ZnO/BDDE, 5 different modified electrodes were prepared with the same composition and conditions. The interday repeatability of the modified electrode was calculated as 3.13 (RSD%) and 1.05 (RSD%) for interday peak current and peak potential, respectively. The applicability of this method was confirmed by analysis of commercial drug tablets containing MTP as active ingredient. The mean recovery of the developed sensor was 95.6 % ± 1.7.
AtıfScopus14WoS12OpenAlex13İncele - MakaleYalnız künye2023Scopus SJRQ2Novel electrochemical sensor of nebivolol drug used for treatment of hypertension and chronic heart failure
İpek, Yeliz; Koçak, Berna
Nebivolol is a beta-blocker used to treat high blood pressure and heart failure. Nebivolol is a cardiovascular drug in the group of selective beta-blockers (with selective action on the cardiovascular system). It prevents the increase in heart rate and controls the pumping power of the heart. It also has a dilating effect on blood vessels and helps to lower blood pressure with this effect. The ability to analyze nebivolol quickly, simply, economically and reliably is of high importance in two cases. The first is to adjust the drug dosage to be used by the patients, and the second is to provide fast intervention in the drug production process as a result of fast and accurate quality control in drug production and to provide quality control of produced tablets. Since, the boric acid has a good catalytic activity and enhances the peak current intensity, a boric acid‒glutardialdehyde-modified glassy carbon electrode was designed for investigation of electrochemical behavior and quantitative determination of nebivolol (NBV) in this study. Electrochemical reaction peak and the peak current intensity changes with changing NBV concentration provide detection of NBV. The role of glutardialdehyde was to immobilize the boric acid on the electrode surface with its crosslinking ability. The designed electrode was achieved by dropping boric acid‒glutardialdehyde mixture on glassy carbon electrode and drying it at room conditions. By using boric acid‒glutardialdehyde-modified glassy carbon electrode (BA‒GA2/GCE), quantitative analysis of the active drug ingredient (NBV), which is widely used in the treatment of hypertension and chronic heart failure, was carried out sensitively, selectively and at low detection limits with low cost. This electrode exhibited good repeatability and stability for detection of the oxidation peak of NBV. In addition, the working ranges and detection limits of NBV were determined in the optimum experimental conditions. SWV technique was used and according to the results obtained, LOD values for NBV in BR buffer (pH 9) and in urine samples were 1.0 × 10−7 mol L−1 and 4.12 × 10−7 mol L−1, respectively. The feasibility of the developed novel sensor was demonstrated by performing recovery studies with tablet and urine samples containing NBV. The recovery results were 93.10% and 58.16% for urine and tablet samples, respectively. Graphical abstract: [Figure not available: see fulltext.]
AtıfScopus5WoS5OpenAlex5İncele - MakaleYalnız künye2022Scopus SJRQ2Eco-Friendly, Thermal Resistant Cotton Fabric Enhanced with Nano Zinc Borate Powder
İpek, Yeliz
The easy burning of cotton fabrics, which have the widest usage area among natural fibers, is a serious problem. Thus, treatment with an environmental friend flame retardant material is essential for cotton fabrics. Zinc borates are multifunctional fire retardants. They can act as smoke suppressor, flame retardant and spark suppressor. Since they are non-toxic and environmental friend materials, they are ideal flame retardants for fabric treatment. In this study, nano-sized zinc borate (ZnO·3B2O3·7H2O) was synthesized and cotton fabric was treated with zinc borate powder with a novel method. Zinc borates are slightly soluble in water. They were dissolved with aid of ammonia as zinc ammonia borate complexes and were recrystalised on the cotton fabric fibers through the evaporation of ammonia. The burning resistance of treated cotton fabric was investigated. The hardness, hydrophobicity, smoke suppression and burning resistance of untreated and treated cotton fabrics were compared. Since zinc borates have smoke suppression feature, a more slight smoke was observed and a higher rate of carbonization occurred during combustion test of treated cotton fabric compared to the untreated cotton fabric. In addition, the burning rate was reduced from 2.26 cm/s to 1.26 cm/s.
AtıfScopus4WoS3OpenAlex4İncele - MakaleAçık Erişim2022Scopus SJRQ3Electrochemical Detection of Ivermectin Used for the Treatment of COVID-19 with Glutardialdehyde-Modified Glassy Carbon Electrode
Koçak, Berna; İpek, Yeliz
In this study, the surface of the glassy carbon electrode was modified with glutardialdehyde. The modified glassy carbon electrode showed electrocatalytic activity against ivermectin. The glassy carbon electrode modified with glutardialdehyde showed high sensitivity, selectivity, and stability in the determination of ivermectin. The peak current of glutardialdehyde oxidation obtained by differential pulse voltammetry decreased inversely with the ivermectin concentration. Ivermectin inhibited the oxidation reaction of glutardialdehyde and caused a decrease in current. This change made the analysis of ivermectin electrochemically possible. In order to demonstrate the applicability of the developed method in real samples, recovery studies were carried out in tap water and urine. The highest sensitivity (0.45 µA/((µmol·L−1)(cm2))) was achieved with urine sample and the lowest detection limit as 2.66 × 10−6 mol·L−1 was obtained with BRT solution sample. Graphical abstract: [Figure not available: see fulltext.]
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İncele - Derleme MakaleAçık Erişim2021Rare Earth Element Doped ZnO Thin Films and Applications
Ayhan, Nagihan Karaaslan; İpek, Yeliz
In this review, general information has been given about the recent studies on thin film coating techniques, zinc oxide (ZnO) thin films and zinc oxide films doped with rare earth elements (REE). As a thin film coating method, the sol‒gel method is widely used due to its economical nature. However, it has been seen that the magnteron sputter technique is also very popular due to its ease of application. Zinc oxide is a semiconductor with a wide band gap and is easy to produce and to supply. In addition, it does not have negative effects on the environment and human health. All these properties have led to intensive studies on zinc oxide. Due to its optical and electrical properties, it has found many different uses such as solar cells, light emitting diodes, gas sensors and flat panel displays. Recently, various studies have been carried out to improve the properties of zinc oxide and to create new areas of use by doping with rare earth elements.
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İncele - MakaleYalnız künye2021Scopus SJRQ2Developing Antibacterial Cotton Fabric with Zinc Borate Impregnation Process
İpek, Yeliz; Ertekin, Özlem
Cotton fabric is a commonly used textile because of its natural and healthy properties. The chemical structure of cotton consists cellulose with a ratio of over 90 %. Cellulose is a natural polymer and cotton fabric is a quiet useful textile because of its better moisture absorption, softness, and easy care properties. Moisture absorbtion property comes from the cellulosic structure of the fabric. However, its features such as being hydrophilic and inclinable to bacterial growth limits its application areas. Antibacterial cotton fabric may be used for hospital textiles such as hospital gowns, patient clothes, wound bandages; food packaging and storage textiles; home textiles like curtain, bed cover; clothing, etc. In this study, a novel environmentally friendly antibacterial cotton fabric was developed. Flame retardant zinc borate was used as antibacterial agent. For this purpose, zinc borate with a formula of ZnO·3B2O3·7H2O had been synthesized with wet chemical precipitation method and cotton fabric was treated with this material via sol-gel impregnation method. The impregnation method for cotton fabric provided a uniform distribution of zinc borate particles and processing the entire volume of the fiber. This method is also suitable for large quantity production processes. In the microbiological studies, Enterococcus which is commonly associated with the nosocomial infections and food spoilage was used. As a result, the antibacterial activity was observed in the fabrics treated with 0.1 mol·l−1 and 0.2 mol·l−1 concentration of zinc borate solutions.
AtıfScopus16WoS13OpenAlex14İncele - MakaleAçık Erişim2021Influence of particle size, additive ratio and chemical structure of zinc borate on mechanical properties of poly(vinyl chloride)
İpek, Yeliz
Zinc borate (ZB) is a flame retardant and smoke supressant compound of boron. It is widely used to achieve flame resistant polymer composites. Poly(Vinyl Chloride) (PVC) is one of the commercially important polymers that is mostly used for cable insulating, windows, doors, pipes, floorings and toys etc.. On the other hand, PVC releases toxic gases during fire as decomposition products. Zinc borate addition is thought to be a solution for this problem. However, this solution leads a new problem. Zinc borate effects the mechanical properties of the PVC. In the present study, to optimize the contribution of zinc borate, with different formulations (2ZnO·3B2 O3·3.5H2 O and 4ZnO·B2 O3·H2 O), with different additive ratios (1% and 5% by weight) and different particle sizes (nano-sized and micro-sized) were added to the PVC structure and the mechanical and thermomechanical properties of each composite were investigated. Mechanical properties of composites were determined by tensile test, impact test, hardness test while thermomechanical behaviours were detected with dynamic mechanical analysis (DMA). In the perspective of mechanical strength of PVC-ZB composite, additive ratio of ZB was more effective than particle size and chemical formulation of ZB. The additive ratio more than 5% by weight can negatively affect the mechanical strength and quality of the PVC-ZB composite.
AtıfScopus2OpenAlex2İncele - MakaleAçık Erişim2020Scopus SJRQ3Modeling of Drying Processes of Dates (Phoenix, Arecaceae) with Oven or TGA and Microbiological Properties of Fresh and Dried Dates
Ertekin, Özlem; İpek, Yeliz
Drying method, which is one of the oldest preservation methods, is important for preserving fruits. Date palm fruit is an important food in human nutrition due to some vitamins, minerals, sugar, phenolic components, and high fiber content. In the literature, date palm drying was not studied sufficiently in the aspect of mathematical modeling and the effect of drying process on the microbiological properties. In this novel study, date palm drying process was applied with four different temperatures of 50°C, 70°C, 90°C, and 110°C with two different drying techniques; drying with oven and drying with thermogravimetric analysis (TGA). Chemical changes in the date palm structure after drying at different temperatures were investigated with FTIR analysis. Fibrous structure of palm fruit is also exhibited with SEM analysis. On the other hand, microbiological studies were applied both for fresh and dried date palm to observe the drying process effect on the growth of different types of microorganisms. Consequently, drying time decreased with increasing drying temperature while the color of the dried date palm fruit became darker with increasing temperature. However, the chemical structure was not affected. Drying time of oven drying technique was longer than drying with TGA technique. The mathematical model of the drying temperature depending on drying time is calculated as (Formula presented.) for TG-DTA drying experiments and (Formula presented.) for drying process with oven. In addition, the microbiological load has significantly decreased or disappeared with the drying process.
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