Ümit Ay

Ümit Ay
Kocaeli University · Department of Chemistry

Professor

About

30
Publications
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269
Citations

Publications

Publications (30)
Article
An inclusion complex was formed with methyl-β-cyclodextrin (Me-β-CD) and the smallest unit of the macrocyclic family of bathocuproine, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline. With this newly formed fluorescent probe, the quenching effect of heavy metals was investigated. Spectral characterization of the complex was performed by UV-visible an...
Article
A triple isotope dilution GC-ICPMS method for the determination of tributyltin (TBT) was developed and validated to meet the European Water Framework Directive (WFD) requirements. The validation procedure involved the evaluation of trueness, precision (repeatability, intermediate precision), limit of detection (LOD) and limit of quantification (LOQ...
Article
Structural characterization of the Pyrene-Methyl-beta-cyclodextrin (Py-Me-β-CD) complex, obtained in aqueous medium, was carried out through Fourier Transform Infrared spectroscopy (FTIR), X-ray diffractometry (XRD), ¹H NMR and two-dimensional correlated spectroscopy (2D COSY). Thermal characterization of the Py-Me-β-CD complex was performed with d...
Article
Full-text available
A complex of anthracene with methyl-beta-cyclodextrin (A-Me-β-CD) having fluorophoric characteristics was obtained in aqueous medium. Spectroscopic and thermal analyses of the complex were performed by Fourier transform infrared spectroscopy and differential scanning calorimetry-thermogravimetry. The interaction of Me-β-CD and anthracene was also a...
Article
Full-text available
Inclusion complex of naphthalene with methyl-beta-cyclodextrin in water has been formed. The aqueous solutions of the various amounts of Co2+ve Mn2+salts have been added to naphthalene-methyl-beta-cyclodextrin (NAP-Me-β-CD) inclusion complexes. Fluorescence properties of the naphthalene (NAP) compound have been utilized to observe the changes in fl...
Article
Full-text available
Kemometrik yöntemler, Dilovası bölgesindeki 10 lokasyondan alınan yüzey toprak numunelerinin ağır metal (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb ve Zn) kirliliğini değerlendirmek ve ağır metal içeriğini sınıflandırmak için kullanıldı. Veriler, ağır metaller arasındaki ilişkiyi anlamak ve toprak numuneleri sınıflandırmak için kemometrik değerlendirmeye t...
Article
Full-text available
Adsorption of anthracene as polycyclic aromatic hydrocarbon molecule on the pristine multi-walled carbon nanotubes (MWCNTs) and function-alized MWCNTs with polymethyl methacrylate (PMMA) has been investigated in an attempt to explore adsorption mechanisms. The morphology of MWCNTs was observed by a Scanning Electron Microscope. Thermal Gravimetric...
Article
Full-text available
Anthracene was used to form an inclusion complex with methylated-β-cyclodextrin (Me-β-CD) in water. In aqueous Me-β-CD solution, typical fluorescence emission of anthracene was observed. Benesi–Hildebrand's method was used to obtain the stoichiometry of the anthracene–Me-β-CD complex. The Stern–Volmer quenching constants, K sv, and fluorescence qua...
Article
Full-text available
Poly-GPTS was prepared by polymerization of 3-glycidyloxypropyltrimethoxysilane (GPTS) with potassium tert-butoxide ((KOBu)-Bu-t) at 50 degrees C. After this stage, adsorbents poly-GPTS and poly-GPTS/Ti(O)/OH were prepared from hydrolysis of poly-GPTS and mixtures between poly-GPTS and titanium isopropoxide in 1:1mol ratio. The hydrolysis was carri...
Article
Full-text available
In this study, we report results concerning the accumulation of heavy metals in seawater from Izmit Bay. The bay was divided into the three parts: the eastern, the central and the western basins. The goal of this study was to determine levels of heavy metals at various depths in the bay between April 2008 and May 2010. Liquid-liquid extractions wer...
Article
Full-text available
The determination of arsenic in five different extraction environments (acetic acid, EDTA, NaOH, MeOH/H2O, acetonitrile) from baby formulas sold in the market was tested. Total arsenic contents were analyzed with Flow Injection-Hydride Generation-Atomic Absorption Spectrometry (FI-HG-AAS) and Graphite Furnace-Atomic Absorption Spectrometry (GF-AAS)...
Article
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Precipitation flotation conditions of zinc which is an essential element for living organisms are determined by using copper-a-benzoin-oxime as a new type of carrier. The effects of pH change, amounts of α-benzoin-oxime and copper and formation period of related complexes as well as the effect of various other metals are reported. With this method,...
Conference Paper
Full-text available
PAH and PCB concentrations were determined in mussel samples collected from Izmit Bay at the east of marmara Sea. The samples were taken from ten points in spring season and analyzed by gas chromatography after ultrasonic extraction. Total PAH concentrations varied between 2.5-13.9 ng.g-wet wt., while the total PCB concentrations were between 4.2-1...
Conference Paper
Full-text available
Concentrations of Zn, Fe, Mn and Pb were determined in biota, sediment and sea water samples collected seasonally from two stations in the Marmara Sea in Turkey. The levels of Fe and Mn in biota and Zn, Mn and Pb in sediment samples were higher than the previous studies. The order of heavy metal concentrations in all samples was: Fe > Mn > Zn > Pb.
Article
Full-text available
We have developed a cost-effective and sensitive spectrophotometric method for the determination of arsenic at trace level using a new reagent, hexamethylene ammonium-hexamethylenedithiocarbamate (HMA-HMDTC). Here we show that arsenic reacts with HMA-HMDTC in acidic conditions to yield the As(HMDTC)3 complex. We studied the Beer’s law at 256 nm, wh...
Poster
S.K. Bozbas, S.K. Beyaz, F.D. Lamari, Ü. Ay CO2 adsorption analysis on activated carbon at different temperatures IV National Hydrogen Energy Congress (with international participation) Book of Abstract page 379
Article
Full-text available
Colloid precipitate flotation of arsenic from fresh water is applied for preconcentration and separation. Optimal conditions using iron (III) hexamethylenedithiocarbamate as collectors were investigated. Various factors affecting the arsenic recovery, including collector mass, pH of the working medium, electrokinetic potential of the collector part...
Poster
Zeolites are used for many purposes like ion exchange and adsorbent for separation and pre-concentration of trace elements. For example; zeolites can be used as ion-exchangers to remove cationic species from aqueous solutions by replacing them by sodium cations. The Si/Al ratio is important in zeolites for the acidity of the framework, ion exchange...
Article
SummaryA simple method was developed for the determination of cadmium (Cd) and lead (Pb) in milk serum prepared by spontaneous souring, using graphite furnace atomic absorption spectrophotometry. Samples of raw milk were collected from the bulk holding tanks of thirty-six dairy farms in twelve localities in Izmit. The samples were kept at room temp...
Article
An accurate, fast, and simple method for determination of thallium in environmental water samples with Zeeman electrothermal atomic absorption spectrometry (ZETAAS) by previous flotation preconcentration is given. The possibility of using cobalt(III) hexamethylenedithiocarbamate as a colloidal precipitate collector for simultaneous flotation separa...
Article
A fast method for separation of Cd, Cu, Fe, Ni, Pb, Zn, and Tl from seawater before their determination by atomic absorption spectrometry (AAS) is described. The ability of Co(III) hexamethylenedithiocarbamate, Co(HMDTC)3, as a flotation collector for metals from seawater was investigated. The influence of pH of the media, as one of the crucial par...
Article
A fast method for separation of iron, nickel, lead, and zinc from water matrices prior to their atomic absorption spectrometry (AAS) is described. The separation and preconcentration of metals was performed by precipitate colloid flotation with cobalt(III) hexamethylenedithiocarbamate, Co(HMDTC)3, as a new collector. The optimal conditions for flot...
Article
A fast method for separation of Cd, Cu, Fe, Ni, Pb, Zn, and Tl from seawater before their determination by atomic absorption spectrometry (AAS) is described. The ability of Co(III) hexamethylenedithiocarba-mate, Co(HMDTC) 3 , as a flotation collector for metals from seawater was investigated. The influence of pH of the media, as one of the crucial...
Article
Interferences of some metals in the determination of arsenic by hydride generation atomic absorption spectrometry utilizing a quartz tube atomizer were studied. The atomizers were coated under vacuum with Ni, Au, Pd and Cr. The arsenic signal was almost totally suppressed by all the metal coatings and thus the interferences from metal ions in the d...
Article
Full-text available
A MECA technique for the determination of organic and inorganic tin compounds was described. Tributyl tin was determined after an extraction step by gas chromatography-MECA system. Inorganic tin compounds were determined by using a hydride generation system in conjunction with MECA. Our aim was to apply the developed technique to the sea water samp...