Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2023Highly Efficient Spectrophotometric Determination of Cu2+ ion in Aqueous Medium Using a thiosemicarbazone–derivative Ligand
Başoğlu, Aysel; Ocak, Ümmühan; Iyidoğan, Ayşegül Karaküçük
A new simple spectrophotometric method for the determination of Cu2+ ion was developed using an thiosemicarbazone compound, 2-{4-[Bis(2-chloroethyl)amino]benzylidene}-N-[(4-methylthio)phenyl]hydrazinecarbothioamide (TSC). A simultaneous color change was observed (from colorless to bright yellow) by the addition of Cu2+ ion to the TSC ligand solution. The maximum absorbance of the TSC ligand measured at 366 nm was decreased by the presence of Cu2+ ion. The graphs of absorbance obtained by means of the Job’s method and the molar-ratio method proposed a complex formation with a 1:2 Cu2+–TSC ligand stoichiometry. The molar-ratio method with emission measurements also confirmed the stoichiometry. The complex stability constant of TSC–Cu2+ complex (K) was evaluated to be 1.76 × 105. The proposed spectrophotometric method was associated with the change in absorbance at 366 nm owing to the interaction between the TSC ligand and Cu2+ ion. From the spectrophotometric titration data, it was pointed out that TSC ligand (1.5 × 10− 5 mol L-1) selectively reacted with Cu2+ ion in DMSO/water (1:1, v/v, citrate buffer at pH = 6.0). The calibration curve for Cu2+ ion was obtained with a good linearity in the range of 0.0191–0.3241 mg L-1. The detection limit for Cu2+ ion was 0.0063 mg L-1. The proposed method was achievemently implemented in real water samples (drink water, tap water and, distilled water). Satisfactory recoveries were confirmed at three different concentrations. The method presented a relative standard deviation (RSD%) of less than 3.08%.
- MakaleAçık Erişim2020Highly sensitive fluorometric method based on nitrogen-doped carbon dot clusters for tartrazine determination in cookies samples
Gümrükçüoğlu, Abidin; Başoğlu, Aysel; Kolayli, Sevgi; Di̇Nç, Saliha; Kara, Meryem; Ocak, Miraç; Ocak, Ümmühan
Nitrogen-doped carbon nanodots (CDs) were prepared via the solvothermal method, using urea and triethylene glycol as the starting materials. The as-prepared CDs had individual diameters of approximately 100 nm and were in clusters of different sizes. The surface composition and optical properties of the as-prepared CDs were characterized. They exhibited multicolor emission properties in the visible range when excited with a wide wavelength range. The aqueous solution of the CDs was used in highly sensitive tartrazine determination. The fluorescence quenching of the CDs was in a linear relationship with the concentrations of tartrazine in the range of 0.5–30.0 µM. The detection limit of the assay was 0.18 µM. Acceptable recovery results were obtained via spike-recovery experiments on cookie samples.
- MakaleYalnız künye2020Synthesis of Microwave-Assisted Fluorescence Carbon Quantum Dots Using Roasted–Chickpeas and its Applications for Sensitive and Selective Detection of Fe3+ Ions
Başoğlu, Aysel; Ocak, Ümmühan; Gümrükçüoğlu, Abidin
A simple method for the green synthesis of fluorescent carbon quantum dots (CQDs) has been developed by using roasted chickpea as carbon source in one-step without using any chemical. Interestingly, not only the carbon source of CQDs and the whole synthesis procedure are environmentally friendly, but also the synthesized CQDs have shown many advantageous properties such as high fluorescence intensity, excellent photostability, and good water solubility. CQDs which were firstly synthesized from roasted–chickpeas by a microwave-assisted pyrolysis have been characterized using UV-vis absorption spectroscopy, fluorescence spectroscopy, fourier transform infrared spectroscopy (FTIR) spectroscopy, X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). In addition, the details of the structure have been revealed by the electron diffraction (SAED; selected-area electron diffraction) method based on the TEM images. The synthesized CQDs emits blue fluorescence under UV light (at 365 nm). A microwave oven (350 watts) was used to prepare CQDs in 120 s. The effect of various metal ions on the fluorescence intensity of CQDs was investigated in order to determine its utality in the detection of metal ions. It was determined that 1.38 mg/L of Fe3+ ions quenched the fluorescence intensity of the CQDs by 65%. The linear range is observed between 11.25 and 37.50 μM with limit of detection (LOD) and limit of quantification (LOQ) of 2.74 μM and 8.22 μM, respectively. CQDs which are highly selective and sensitive for Fe3+ ions was used to determine Fe3+ ions in certified reference material (CRM-SA-C). Fe3+ ions concentration was determined with precision values of more than 95% as intra-day and inter-day relative standard deviation (RSD%) is 5 at room temperature.
- MakaleAçık Erişim2018A rapid and sensitive spectrofluorometric method for the determination of au(III) based on fluorescence quenching of a 1,3,5-triphenyl-2-pyrazoline
Başoğlu, Aysel; Ocak, Ümmühan; Fandakli, Seda; Yayli, Nurettin
A simple, rapid, sensitive, and low-cost spectrofluorometric method was developed for the determination of Au(III) using 5-(2,3-dimethoxyphenyl)-3-(4-methoxyphenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (L) in ethanol/water. The method is based on the change in the fluorescence intensity at 464 nm after excitation at 355 nm as a result of the reaction between the ligand and Au(III). The fluorescent emission of ligand at 464 nm decreased with the increasing of Au(III) concentration. The ligand concentration, pH effect, response time, and effect of foreign ions were determined. From the results of fluorescence titration experiments, it was found that the ligand (1 × 10−7 M) was selective and sensitive to Au(III) in EtOH-H2 O (1:1, v/v, phthalate buffer, pH 4.0). The calibration curve showed good linearity in the concentration range of 17.4–237.6 µg L−1 Au(III). The limits of detection and quantification were 5.2 and 17.4 µg L−1 Au(III) with a response time of 1 min, respectively. Satisfactory accuracy was obtained for standard reference material (CRM-SA-C Sandy Soil C). The proposed method was successfully applied to the determination of Au(III) in tap water, sea water, and stream water samples, and high levels of recovery were obtained.