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Öğe Determination of Ascorbic Acid in Tablet Dosage Forms and Some Fruit Juices by DPV(Esg, 2008) Yilmaz, Selehattin; Sadikoglu, Murat; Saglikoglu, Gulsen; Yagmur, Sultan; Askin, GokceAscorbic acid, a water-soluble vitamin, is the most common electroactive biological compound found in some fruit species. The electrochemical oxidation of ascorbic acid was investigated at glassy carbon electrode in various aqueous solutions in the pH range of 0.64-10.15 (in Britton-Robinson, acetate, phosphate buffers and 0.5 mol L-1 sulphuric acid solutions) by cyclic (CV) and differential pulse (DPV) voltammetry. For the quantitative purposes, a very well-resolved diffusion-controlled voltammetric peak was obtained in 0.2 mol L-1 acetate buffer (pH 3.49) at 0.342 V by DPV technique. The linear response was obtained in the concentration range of 6x10(-6)-8x10(-4) mol L-1 with a detection limit (LOD) of 5.17x10(-7) and quantitative limit (LOQ) of 1.72x10(-6) mol L-1. Ascorbic acid in pharmaceutical dosage forms and some fruit juices were determined by DPV. The reliability of the proposed voltammetric technique was established by recovery studies.Öğe Determination of total Cr in wastewaters of Cr electroplating factories in the I.organize industry region (Kayseri, Turkey) by ICP-AES(Springer, 2010) Yilmaz, Selehattin; Ture, Melike; Sadikoglu, Murat; Duran, AliThe wastewater pollution in industrial areas is one of the most important environmental problems. Heavy metal pollution, especially chromium pollution in the wastewater sources from electroplating, dyeing, and tannery, has affected the life on earth. This pollution can affect on all ecosystems and human health directly or by food chain. Therefore, the determination of total chromium in this study is of great importance. In this study, accurate, rapid, sensitive, selective, simple, and low-cost technique for the direct determination of total Cr in wastewater samples collected from the some Cr electroplating factories in March 2008 by inductively coupled plasma-atomic emission spectrometry has been developed. The analysis of a given sample is completed in about 15 min by this technique applied. As the result of the chromium analysis, the limit of quantification for the total Cr were founded to be over the limit value (0.05 mg L (-aEuro parts per thousand 1); WHO, EPA, TSE 266, and inland water quality classification) as 1,898.78 +/- 0.34 mg/L at station 1 and 3,189.02 +/- 0.56 mg/L at station 2. The found concentration of total Cr has been determined to be IV class quality water according to the inland water classification. In order to validate the applied method, recovery studies were performed.Öğe Direct Determination of Zn Heavy Metal in Tap Water of Canakkale (TURKEY) by Anodic Stripping Voltammetry Technique(Electrochemical Science Group, 2009) Yilmaz, Selehattin; Yagmur, Sultan; Saglikoglu, Gulsen; Sadikoglu, MuratIn this work, the direct determination of zinc heavy metal in the tap water was carried out by differential pulse anodic stripping voltammetry (DPASV) technique at the glassy carbon electrode (GCE). The zinc ions were deposited by reduction at -1.5 V on a bare glassy carbon surface. Then, the deposited metal was oxidized by scanning the potential of the electrode surface from -1.5 to -0.8 volt using a differential puls mode. The stripping current arising from the oxidation of metal was connected with the concentration the metal in the sample. The concentration of zinc heavy metal found in tap water sample was determined to be 180 mu g L(-1) using 0.2 mol L(-1) acetate buffer (pH: 3.50).Öğe Electroanalytical and HPLC Methods for the Determination of Oxcarbazepine in Spiked Human Urine and Tablet Dosage Form(Croatian Chemical Soc, 2014) Nosal-Wiercinska, Agnieszka; Yilmaz, Selehattin; Binel, Sevcan; Yagmur, Sultan; Saglikoglu, Gulsen; Sadikoglu, Murat; Yıldız, MustafaIn this study, the electrochemical reduction and determination of oxcarbazepine were easily realized in various buffer solutions in the pH range of 4.50 to 11.15 in real samples using glassy carbon electrode (GCE) by cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques. The influence of pH on the cathodic peak current and peak potential was investigated. Scan rate studies were also completed. The diffusion controlled nature of the peak was established. The best results for the quantitative determination of oxcarbazepine were obtained by DPV technique in Britton-Robinson (BR) buffer (pH 8.05). In this basic medium, one irreversible and sharp cathodic peak was observed. A linear calibration curve for DPV analysis was constructed in the oxcarbazepine concentration range of 8x10(-6) to 1x10(-4) M. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 1.65x10(-6) and 5.51x10(-6) M, respectively. Repeatability, reproducibility, precision and accuracy of the developed technique were checked in spiked human urine and tablet dosage forms by recovery studies and results of the high performance liquid chromatography (HPLC) technique. A reduction mechanism for the electrode reaction was proposed.Öğe Electroanalytical determination of metronidazole in tablet dosage form(Serbian Chemical Soc, 2013) Yilmaz, Selehattin; Baltaoglu, Esra; Saglikoglu, Gulsen; Yagmur, Sultan; Polat, Kamran; Sadikoglu, MuratIn this study, the electrochemical reduction and determination of metronidazole were easily realized in Britton-Robinson buffer (pH 4.01) using an UTGE by cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques. In this acidic medium, one irreversible and a sharp cathodic peak were observed. A linear calibration curve for DPV analysis was constructed in the metronidazole concentration range 3 x10(-6)-9x10(-5) mol L-1. The limit of detection (LOD) and limit of quantification (LOQ) were 1.42x10(-7) and 4.76x10(-7) mol L-1 respectively.Öğe Electrocatalytic Oxidation of Acyclovir on Poly(p-Aminobenzene Sulfonic Acid) Film Modified Glassy Carbon Electrode(Wiley-V C H Verlag Gmbh, 2015) Can, Saide; Yilmaz, Selehattin; Saglikoglu, Gulsen; Sadikoglu, Murat; Menek, NecatiAcyclovir is an antiviral effective drug active compound. A glassy carbon electrode (GCE) was modified with an electropolymerized film of p-aminobenzene sulfonic acid (p-ABSA) in phosphate buffer solution (PBS). The polymer film-modified electrode was used to electrochemically detect acyclovir. Polymer film showed excellent electrocatalytic activity for the oxidation of acyclovir. The anodic peak potential value of the acyclovir at the poly(p-ABSA) modified glassy carbon electrode was 950mV obtained by DPV. A linear calibration curve for DPV analysis was constructed in the acyclovir concentration range 2x10(-7)-9x10(-6)molL(-1). Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 5.57x10(-8) and 1.85x10(-7)molL(-1) respectively. The proposed method exhibits good recovery and reproducibility.Öğe Electrochemical Determination of Phenazopyridine Hydrocloride using Poly(p-Aminobenzene Sulfonic Acid) Film Modified Glassy Carbon Electrode(Esg, 2015) Demirtas, Cigdem; Yilmaz, Selehattin; Saglikoglu, Gulsen; Sadikoglu, MuratPhenazopyridine hydrochloride is an antiviral effective drug active compound. A glassy carbon electrode (GCE) was modified with an electropolymerized film of p-aminobenzene sulfonic acid (p-ABSA) in phosphate buffer solution (PBS). The electrochemical properties of the polymer film were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The polymer film-modified electrode was used to electrochemically detect phenazopyridine hydrochloride. Polymer film showed excellent electrocatalytic activity for the reduction of phenazopyridine hydrochloride. The catodic peak potential value of the phenazopyridine hydrochloride at the poly(p-ABSA) modified glassy carbon electrode was -334 mV obtained by DPV. A linear calibration curve for DPV analysis was constructed in the phenazopyridine hydrochloride concentration range 6x10(-6)-1x10(-5) mol L-1. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 2.1x10(-7) and 7x10(-7) mol L-1 respectively. The proposed method exhibits good recovery and reproducibility. The mechanisms of electropolymerization of p-ABSA are also suggested.Öğe Investigation of some disinfection chemicals and water quality parameters in swimming pools in the city center and districts of Canakkale, Turkey(Springer, 2017) Uysal, Tolga; Yilmaz, Selehattin; Türkoğlu, Muhammet; Sadikoglu, MuratIn this study, the variations in concentrations of some disinfection chemicals such as cyanuric acid (CyA), free chlorine (FC), and residual chlorine (RC), which affect human health, were investigated in the water of swimming pools. In addition, quality parameters such as temperature, pH, and total alkalinity (TA) in 44 swimming pools located in the city center and districts of Canakkale, Turkey, were examined in the summer period. While FC and RC amounts were analyzed using tablet tests with N-N-diethyl phenylenediamine (DPD 1) and potassium iodine (DPD 3) using the colorimetric method in the comparator, TA and CyA levels were measured with a photometric method. Temperature and pH were measured using YSI 556 MPS. Levels of CyA, FC, RC, pH, temperature, and TA varied between 0.00 and 725.0 mg L-1 (108.0 +/- 111.4 mg L-1), 0.00 and 5.00 mg L-1 (1.60 +/- 0.962 mg L-1), 0 and 0.55 mg L-1 (0.087 +/- 0.059), 6.40 and 8.20 mg L-1 (7.30 +/- 0.038 mg L-1), 22.0 and 32.0 degrees C (27.6 +/- 1.45 degrees C), and 0.00 and 391.0 mg L-1 129.3 +/- 89.0), respectively. The findings were compared to standard limit values of the Ministry of Health of the Turkish Republic and other countries. Not only maximum concentrations of CyA but also the average concentrations exceeded the standard limit values of different countries in July and August with high tourism activity in Turkey. Although there is no problem in view of average values of other quality parameters, there are some problems in view of the maximum values in pool waters compared to standard limit values.Öğe Seasonal variations in tap water quality parameters in Çanakkale, Türkiye(2022) Kacar, Hasan; Yılmaz, Selehattin; Türkoğlu, Muhammet; Sadikoglu, MuratWater pollutants are a major problem for the world. Especially, heavy metals are significant environmental pollutants due to their tendency on accumulation in organisms and causing toxic effects on humans, animals, and aquatic organisms. Therefore, qualitative and quantitative analyses of pollutants are important. Especially the analysis of contaminants in tap water is important. In this study, unlike previous studies, physicochemical water quality parameters were also studied for the first time along with heavy metal analysis. Water-quality parameters (pH, temperature, conductivity, and dissolved oxygen) were determined in tap-water by YSI 556 MPS, other parameters such as biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were determined by electrometric and titrimetric methods. Various anions were analysed with the UV-VIS spectroscopy technique. Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were analysed as pollutants by ICP-OES. Amount of Cr, Cd, Ni, and Pb were found as detectable limits, but Cu, Fe, Mn, and Zn were found 0.003 ppm, 0.173 ppm, 0.009 ppm, and 2.343 ppm, respectively. The pH of the tap water was in the interval 6.64 and 7.12 (mean: 6.85 ± 0.12). Nitrite varied between 0.20 and 0.60 mg/L (average: 0.36±0.001 mg/L) revealing that the tap waters exceeded the TSE standards for first quality drinking waters (0.20 mg/L). The data were evaluated using the relevant statistical analysesÖğe Sensitive Determination of Quercetin in Onion Peel by Voltammetry Using a Poly(4-Aminobenzene Sulfonic Acid) Modified Glassy Carbon Electrode(Univ Tehran, Fac Chemistry, Center Excellence Electrochemistry, 2017) Selvi, Bedrettin; Sadikoglu, Murat; Soylu, Umit Ilay; Yilmaz, Selehattin; Onal, Adem; Eser, FerdaPoly 4-aminobenzene sulfonic acid modified glassy carbon electrode (poly(4ABSA/GCE)) was prepared with electrochemical polymerization technique in phosphate buffer solution (PBS) (pH 7.0). The modified glassy carbon electrode (GCE), which has high electrooxidation ability in the pH range of 5-10 with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques, was successfully developed for the electrochemical determination of quercetin (QR). However, the QR or the products of the oxidation reaction are adsorbed strongly on the modified glassy carbon surface. Therefore, when subsequent sweeps of the CV and DPV voltammograms were recorded, a decrease was observed at the peak current and at peak potential there was a shift to a lower positive potential. The best results for the quantitative determination of QR were obtained by DPV technique in 0.1 M PBS (pH 8.0). A linear calibration curve for DPV analysis was constructed in the QR concentration range of 7x10(-5) to 9x10(-4) M. The method was applied for the analysis of QR in onion peel.Öğe Sensitive voltammetric determination of famotidine in human urine and tablet dosage forms using an ultra trace graphite electrode(Serbian Chemical Soc, 2014) Yagmur, Sultan; Yilmaz, Selehattin; Saglikoglu, Gulsen; Uslu, Bengi; Sadikoglu, Murat; Ozkan, Sibel A.In this study, the direct and sensitive determination of famotidine based on its electrochemical oxidation was investigated in spiked human urine and tablet dosage forms. The electrochemical measurements were performed in various buffer solutions in the pH range 0.88-12.08 at an ultra trace graphite electrode (UTGE) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The best results were obtained for the quantitative determination of famotidine by the DPV technique in 0.5 mol L-1 H2SO4 solution (pH 0.30). In this strong acid medium, one irreversible anodic peak was observed. The effects of pH and scan rate on the peak current and peak potential were investigated. The diffusion-controlled nature of the peak was established. For optimum conditions described in the experimental section, a linear calibration curve for DPV analysis was constructed in the famotidine concentration range 2x10(-6)-9x10(-5) mol L-1. The limit of detection (LOD) and limit of quantification (LOQ) were 3.73x10(-7) and 1.24x10(-6) mol L-1 at a UTGE, respectively. The repeatability, precision and accuracy of the developed technique were checked by recovery studies in spiked urine and tablet dosage forms.Öğe Sensitive Voltammetric Determination of Paracetamol on Poly(4-Aminobenzene Sulfonic Acid) Modified Glassy Carbon Electrode(Esg, 2016) Yilmaz, Selehattin; Bas, Zeynep; Sadikoglu, Murat; Yagmur, Sultan; Saglikoglu, GulsenA poly (4-aminobenzene sulfonic acid) (4-ABSA) modified glassy carbon electrode (GCE) was prepared for the quantitative determination of paracetamol (PCT). The 4-ABSA-modified GCE was prepared by electrochemical polymerization method in phosphate buffer solution (PBS) (pH 7.0). The polymer film-modified electrode has high catalytic ability for electrooxidation of PCT, which appeared at pH range of 5-8 by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The best results for the determination of PCT were obtained by DPV in PBS (pH 7.00). Calibration curve was obtained in the PCT concentration range of 6x10(-7) to 9x10(-6) mol L-1 by DPV. Limit of detection (LOD) and quantification (LOQ) were found as 9.33x10(-8) mol L-1 and 3.10x10(-7) mol L-1, respectively. The results of experiments indicated that modified electrode have good stability, sensitivity and reproducibility for at least one month if stored dry in air.Öğe Study of heavy metal pollution in seawater of Kepez harbor of Canakkale (Turkey)(Springer, 2011) Yilmaz, Selehattin; Sadikoglu, MuratIn this work, the heavy metals cadmium and lead in Kepez harbor were studied with regard to the determination of the environmental pollution levels. Seawater samples of the Dardanelles (Canakkale Strait) were collected from the nearest station to Kepez harbor in July 2007. Then, the concentrations of these metals were determined after simple pretreatment of samples by the proposed inductively coupled plasma-atomic emission spectrometry (ICP-AES) method. The analysis of a given sample is completed in about 15 min by the ICP-AES method, and the concentrations of Cd and Pb were found to be 73.80 mg L-1 (relative standard deviation [RSD], 1.07%) arid 9.39 mg L-1 (RSD, 0.70%), respectively. The accuracy of the applied ICP technique was checked by recovery studies, and good recoveries were obtained. The pollution levels of Cd and Pb recorded in this study were compared with those in other studies to analyze the water sample in Kepez harbor.Öğe Synthesis, spectroscopic studies and electrochemical properties of Schiff bases derived from 2-hydroxy aromatic aldehydes and phenazopyridine hydrochloride(Serbian Chemical Soc, 2013) Yagmur, Sultan; Yilmaz, Selehattin; Saglikoglu, Gulsen; Sadikoglu, Murat; Yıldız, Mustafa; Polat, KamranNovel Schiff bases 1-4 were synthesized by the reaction of 2-hydroxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 2-hydroxy-5-nitrobenzaldehyde and 2-hydroxy-1-naphthaldehyde with phenazopypridine hydrochloride (PAP), respectively, and their structures were elucidated by means of spectroscopic techniques. The electrochemical reduction of PAP and its Schiff bases (1-4) were realized on a glassy carbon electrode (GCE) in dimethyl sulfoxide (DMSO) using the cyclic voltammetric (CV) technique. The effect of functional groups on reduction potential of the Schiff bases was investigated. A general electrochemical reduction mechanism of the compounds is suggested.Öğe Voltammetric Determination of Acyclovir in Human Urine Using Ultra Trace Graphite and Glassy Carbon Electrodes(Bentham Science Publ Ltd, 2011) Sadikoglu, Murat; Saglikoglu, Gulsen; Yagmur, Sultan; Orta, Erdem; Yilmaz, SelehattinAn electroanalytical method was developed for the direct quantitative determination of Acyclovir (Acy) in spiked human urine base on its oxidation behavior. The electrochemical oxidation and determination of Acy were easily carried out on ultra trace graphite electrode (UTGE) and glassy carbon electrode (GCE) using a variety of voltammetric techniques. The electrochemical measurements were carried out on these electrodes in various buffer solutions in the pH range of 3.66 to 9.08 by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The best results for the quantitative determination of Acy were obtained by DPV technique in 0.2 M acetate buffer (pH=4.66). In this acidic medium, one irreversible anodic peak was observed. The anodic peak current and peak potential depend on pH and scan rate were studied. The diffusion controlled nature of the peak was established. Acy was determined in the concentration range from 4x10(-6) to 7x10(-5) molL(-1) for UTGE and 2.0x10(-6) to 1.0x10(-4) molL(-1) for GCE by the applied electroanalytical procedure. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 1.0x10(-6) and 3.3x10(-6) molL(-1) on UTGE and 3.5x10(-7) and 1.2x10(-6) molL(-1) on GCE, respectively. Repeatability, precision and accuracy of the developed technique were checked by recovery studies in spiked urine.
