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 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 SJRQ3Eco-Friendly and Practical Electrochemical Determination of Lactic Acid in Milk Using Boron Doped Diamond Electrode
İpek, Yeliz.; Koçak, Berna; Keçeci, Ali
In this study, an economical, environmentally friendly, sensitive, selective, and rapid voltammetric quantitative analysis method was developed using a boron doped diamond electrode to determine lactic acid (LA). Two linear working ranges were determined for LA determination in phosphate buffer solution (PBS, pH of 2). The first linear working range (LR1) was between concentrations of 1.5 × 10−6–8 × 10−6 mol· L−1, with a detection limit of 1.3 × 10−6 mol·L−1, and the limit of quantification (LOQ) was found to be 4.4 µmol· L−1. The second linear working range (LR2) was determined in the concentration range of 8.0–89.2 µmol·L−1. LOD was calculated as 15.8 µmol·L−1, and the LOQ value was calculated as 52.6 µmol·L−1 in the LR2. Intraday repeatability of the BDD electrode for LA determination was (RSD) 6.8% in LR1 and 11.8% in LR2. The interday repeatabilities of the BDD electrode in LR1 and LR2 were calculated as 7.7% and 4.7%, respectively. The developed electrochemical sensor was successfully applied for the determination of LA in milk sample. The sensor exhibited a short response time of about 10 s in PBS at pH 2. The recovery values of LA in PBS and milk sample were 97.3% and 96.1%, respectively.
AtıfScopus2WoS2OpenAlex2İncele - 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 SJRQ3A Selective and Sensitive Electrochemical Sensor for Pyridoxine Hydrochloride (Vitamin B6) in Pharmaceutic Tablet
Koçak, Berna
In this study, a copper (II) oxide-glutardialdehyde modified boron doped diamond electrode was used as a sensor for the electroanalysis of pyridoxine hydrochloride (vitamin B6) for the first time. A copper oxide-glutardialdehyde modified boron doped diamond electrode (CuO-GA2/BDDE) was prepared by a simple drop casting method on boron diamond electrode (BDDE) by suspending CuO with glutardialdehyde (CuO-GA2). The electrochemical behavior of vitamin B6 was examined using cyclic voltammetry (CV) and its electrochemical determination was found by differential pulse voltammetry (DPV). Under optimum experimental conditions, the linear working range of vitamin B6 on CuO-GA2/BDDE via the DPV method was calculated as 5.96×10−6–3.75×10−4 mol.L−1. The limit of detection (LOD) was calculated as 1.99×10−7 mol.L−1. In order to demonstrate the selectivity of the method improved for the quantitative determination of vitamin B6 on the CuO-GA2/BDDE, the interference effect of some cations (Zn2+, Cu2+, Pb2+) and anions (NO3−, Cl−) was investigated via the DPV method. The improved electrode was successfully used for the electroanalysis of vitamin B6 in a tablet sample of the commercial Tribeksol® (deva) (250/250/1 mg B1+B6+B12).
AtıfScopus7WoS6OpenAlex6İncele - 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 - 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 - MakaleAçık Erişim2021Klorpirifosun Gerçek Örnekte Tayini İçin Yeni ve Yüksek Hassasiyetli İndirgenmiş Grafen Oksitle Modifiye Edilmiş Elektrokimyasal Sensör
Koçak, Berna; Çelikkan, Hüseyin
Bu çalışmada, klorpirifosun(CPF) voltametrik davranışı, indirgenmiş grafen oksitle modifiye edilmiş camsı karbon elektrot(RGO/GCE) kullanılarak incelendi. Hummers yöntemiyle hazırlanan grafen oksit ve indirgenmiş grafenoksitin karakterizasyonunda FT-IR, XRD ve TEM yöntemleri kullanıldı. CPF'nin elektrokimyasal karakterizasyonu, dönüşümlü voltametri(CV) ve diferansiyel puls voltametriyle(DPV) ile belirlendi. RGO/GCE'ta CPF'nin tayini diferansiyel puls adsorptif sıyırma voltametrisiyle(DPAdSV) yapıldı. RGO/GCE'ta CPF'nin DPAdSV yöntemiyle oluşturulan kalibrasyon grafiğinde 5.19x10^{-7}-8.12x10⁻⁶M ve 8.12x10^{-6}-2.18x10⁻³M olmak üzere iki çalışma aralığı belirlendi. LOD değeri 1.56x10^{-7}$M'dir. RGO / GCE ile musluk suyu örneklerinde CPF geri kazanımı %101,0'dir. Sonuç olarak,CPF tayini için gerçek numunelerde kullanılabilen seçici ve duyarlı bir sensör geliştirilmiştir.
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İncele - MakaleAçık Erişim2021Voltammetric Determination of Ethalfularin on Glassy Carbon Electrode and Nafion-Graphene Modified Glassy Carbon Electrode
Koçak, Berna
In this study, the electrochemical behavior of ethalfluraline (ETF), a dinitroaniline group herbicide, onglassy carbon electrode(CKE) and nafion-graphene modified glassy carbon electrode(N-GR /CKE) was investigatedby cyclic voltammetry(CV). Voltammetric determination of ETF was examined by differential pulsevoltammetry(DPV). Two peaks observed at -0.942V(1st peak current) and -0.768V(2nd peak current) during thepotential scan of EFT by DPV method in pH 7 phosphate buffer solution between 0 and -1.5V on CKE and at -0.674V(1st peak current) and -0.563 V(2nd peak current) during the potential scan on N-GR/CKE. After determining theoptimum experimental conditions of ETF on CKE and N-GR /CKE, calibration line, working range, limit ofdetection(LOD), limit of quantification(LOQ), intra-day and inter-day repeatability were determined. In addition, the interference effect of some cations(Cu²⁺, Ni²⁺, Co²⁺, Ca²⁺, Pb²⁺) on N-GR/CKE was also investigated.The results show that EFT can be determined in real samples(water and soil) using CKE and N-GR/CKE.
- MakaleAçık Erişim2021Voltammetric Determination of Pendimethalin with Nafion-Graphene Modified Glassy Carbon Electrode
Koçak, Berna; Çelikkan, Hüseyin
In this study, the voltammetric behavior of pendimethalin was investigated at a glassy carbon electrode (GCE) and a nafion-graphene\rmodified glassy carbon electrode (n-GR/GCE). The electrochemical characterization of pendimethalin was carried out using cyclic\rvoltammetry (CV) technique. For the determination studies performed with GCE, the differential pulse voltammetry (DPV) technique\rwas employed, while the differential pulse adsorptive stripping voltammetry (DPAdSV) method was used for the determination\rstudies with n-GR/GCE. First of all, optimal experimental conditions were established for both electrodes, a calibration curve was\rplotted and linear working ranges were identified. For the 1st peak current of pendimethalin, the working range of the calibration\rcurve drawn by DPV technique with GCE was 1.56×10-6-1.08×10-3 M with the limit of detection (LOD) value calculated as 3.09×10-5\rM. For the 2nd peak current of pendimethalin, the working range of the calibration curve created by DPV technique with GCE was\r1.56×10-6-9.73×10-4 M and the LOD value was found to be 3.36×10-6 M. For the 1st peak current of pendimethalin, the working range\rof the calibration curve constructed by DPAdSV technique with n-GR/GCE was determined to be 1.76×10-6-4.01×10-4 M with the\rLOD value being 8.69×10-6 M. For the 2nd peak current of pendimethalin, the working range of the calibration curve obtained by\rDPAdSV technique with n-GR/GCE was 1.96×10-9-7.53×10-4 M with the LOD value calculated as 1.05×10-9 M.
AtıfOpenAlex2İncele - MakaleYalnız künye2015Scopus SJRQ1Stripping voltammetric analysis of dicofol on graphene-modified glassy carbon electrode
Koçak, Berna; Er, Engin; Çelikkan, Huseyin
This study is related to the development of a highly sensitive and selective electrode for the electroanalysis of dicofol (DCF) by the modification of a glassy carbon electrode (GCE) with graphene (GR) nanosheets. GR was characterized by Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), transmission electron microscopy (TEM), and electrochemical methods. The electrochemical reduction of DCF was observed on both bare GCE and GR-modified GCE (GRE). The electrochemical reaction of DCF on GRE was observed to be an adsorption controlled. Differential pulse stripping voltammetry was chosen in the electrochemical analysis of DCF, and two linear calibration ranges from 5.0 x 10(-8) to 5.0 x 10(-7) M and from 5.0 x 10(-7) to 4.2 x 10(-4) M were obtained with a low detection limit of 1.08 x 10(-7) M (N = 5) under the optimized experimental conditions. The electrode developed was successfully used to monitor dicofol in a series of spiked samples.
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