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    Concentrations of cadmium and lead heavy metals in Dardanelles seawater
    (Springer, 2007) Suren, Esin; Yilmaz, Selahattin; Türkoğlu, Muhammet; Kaya, Selahattin
    Cadmium and lead were determined simultaneously in seawater by differential pulse stripping voltammetry (DPSV) preceded by adsoptive collection of complexes with 8-hydroxyquinoline (oxine) on to a hanging mercury drop electrode (HMDE). In preliminary experiments the optimal analytical condition for oxine concentration was found to be 2.10(-5) M, at pH 7.7, the accumulation potential was -1.1 V, and the initial scannig potential was -0.8 V. The peak potentials were found -0.652 V for Cd and -0.463 V for Pb At the 60 s accumalation time. The limit of detection (LOD) and limit of quantitatification (LOQ) were found to be by voltammetry as 0.588 and 1.959 mu g l(-1) (RSD, 5.50%) for Cd and 0.931 and 3.104 mu g l(-1) (RSD, 4.10%) for Pb at 60 s stirred accumulation time respectively. In these conditions the most of the seawater samples are amenable for direct voltammetric determination of cadmium and lead using a HMDE. An adsorptive stripping mechanism of the electrode reaction was proposed. For the comparison, seawater samples were also analysed by ICP-atomic emission spectrometry method (ICP-AES). The applied voltammetric technique was validated and good recoveries were obtained.
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    Determination of heavy metal pollution with environmental physicochemical parameters in waste water of Kocabas Stream (Biga, Canakkale, Turkey) by ICP-AES
    (Springer, 2007) Yayintas, Ozlem Tonguc; Yilmaz, Selahattin; Türkoğlu, Muhammet; Dilgin, Yusuf
    Waste water pollution of industrial areas can answer for the serious consequences of one of the most important environmental threats to the future. In this study, inductively coupled plasma-atomic emission spectrometry method (ICP-AES) is proposed to determine heavy metals (Pb, Cu, Cd, Cr, Zn, Al, Fe, Ni, Co, Mn) and major elements (Ca, Mg) in waste water of Kocabas Stream. The concentration of metals in the waste water samples taken from 9 different stations (St.) in Biga-Kocabas Stream in November 2004 (autumn period) were determined after simple pretreatment of samples by the proposed ICP-AES method. An analysis of a given sample is completed in about 15 min for ICP-AES the method. The results of heavy metals concentrations in waste water were found between 0.00001-77.69610 mg l(-1) by the ICP-AES technique. The concentrations of Pb, Cd, Cu, Zn, Cr, Al, Fe, Mn, Ni, Co, Mg and Ca 0.00001 (St.3,6,7) - 0.0087 mg l(-1) (St.9), 0.00001 (St.4-7) - 0.0020 mg l(-1) (St.8), 0.00001 (St.1,3-7,9) - 0.0041 mg l(-1) (St.2), 0.0620 (St.2) - 0.2080 mg l(-1) (St.3), 0.0082 (St.6) - 0.2290 mg l(-1) (St.8), 0.3580 (St.2) - 1.7400 mg l(-1) (St.3), 0.2240 (St.1) - 0.6790 mg l(-1) (St.3), 0.0080 (St.1) - 1.5840 mg l(-1) (St.3), 0.0170 (St.3) - 0.0640 mg l(-1) (St.2), 0.0010 (St.1,4,5,8) - 0.0080 mg l(-1) (St.3), 5.0640 (St.9) - 5.2140 mg l(-1) (St.1) and 43.3600 (St.2) - 77.6961 mg l(-1) (St.9), respectively. Also we measured environmental physicochemical parameters such as temperature, salinity, specific conductivity, total dissolved solid (TDS), pH, oxidation and reduction potential (ORP), and dissolved oxygen (DO) in the waste water at sampling stations.
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    Öğe
    Electrochemical behaviour of 5-(furan-2-yl)-4-(p-tolyl)-2,4-dihydro-1,2,4- triazole-3-thione by using glassy carbon electrode
    (Chemical Publishing Co., 2007) Dilgin, Yusuf; Cansiz, Ahmet; Çetin, Ahmet; Kutulay, Pelin; Oral, Ayhan; Yilmaz, Selahattin
    The electrochemical study of a thiotriazole compound, 5-(furan-2-yl)-4-(p- tolyl)-2,4-dihydro-1,2,4-triazole-3-thione (TTA) was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using glassy carbon electrode (GCE) as working electrode and an Ag/AgCl reference electrode. The dependence of the current on pH and scan rate was investigated in the Britton Robinson Buffer. The best results for electrooxidation of TTA were obtained in basic media (pH 11.0 containing 5 % DMSO). This compound display one irreversible oxidation peak, which is attributed to a dimerization process involving the formation disulphide derivative.
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    Öğe
    Electrochemical behaviour of 5-(Furan-2-yl)-4-(p-tolyl)-2,4-dihydro-1,2,4-triazole-3-thione by using glassy carbon electrode
    (Asian Journal Of Chemistry, 2007) Dilgin, Yusuf; Cansiz, Ahmet; Cetin, Ahmet; Kutulay, Pelin; Oral, Ayhan; Yilmaz, Selahattin
    The electrochemical study of a thiotriazole compound, 5-(furan-2-yl)-4-(p-tolyl)-2,4-dihydro-1,2,4-triazole-3-thione (TTA) was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using glassy carbon electrode (GCE) as working electrode and an Ag/AgCl reference electrode. The dependence of the current on pH and scan rate was investigated in the Britton Robinson Buffer. The best results for electrooxidation of TTA were obtained in basic media (pH 11.0 containing 5 % DMSO). This compound display one irreversible oxidation peak, which is attributed to a dimerization process involving the formation disulphide derivative.
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    Öğe
    Electrochemical oxidation of prednisolone at glassy carbon electrode and its quantitative determination in human serum and tablets by Osteryoung square wave voltammetry
    (Bentham Science Publ Ltd, 2007) Yilmaz, Selahattin; Skrzypek, Slowomira; Dilgin, Yusuf; Yagmur, Sultan; Coskun, Mahmut
    A simple, rapid, selective and sensitive electrochemical method for the direct determination of prednisolone in spiked human serum and tablets was developed. The electrochemical oxidation and determination of prednisolone has been carried out at glasy carbon electrode (GCE) in various aquaeous solution in the pH range of 0.56-12.30 by cyclic (CV) and Osteryoung square wave voltammetry (OSWV). The best results were obtained for the determination of prednisolone by OSWV method in 0.5 mol L-1 sulphuric acid at about pH 0.56. The peak current and peak potential depends on pH, so its influence and also scan rate were studied. The diffusion controlled by nature of the peak was established. This electroanalytical procedure enabled to determine prednisolone in the concentration range 1.0 X 10(-6)- 2.0 x 10(-5) mol L-1. This limit of detection (LOD) and limit of quantification (LOQ) were obtained as 3.4x10(-7) and 4.5x 10(-7) mol L-1 respectively. Precision and accuracy of the developed method were checked by recovery studies in spiked tablets and human serum.
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    Öğe
    Osteryoung square wave voltammetric determination of phenazopyridine hydrochloride in human urine and tablet dosage forms based on electrochemical reduction at carbon paste electrode
    (Bentham Science Publ Ltd, 2007) Citak, Meryem; Yilmaz, Selahattin; Dilgin, Yusuf; Tuerker, Guelen; Yagmur, Sultan; Erdugan, Hueseyin; Erdugan, Necla
    An electroanalytical method was developed for the direct quantitative determination of phenazopyridine hydrochloride (PAP) or in other words, pyridium, in spiked human urine and tablet dosage forms. The electrochemical reduction and determination of PAP were carried out at carbon paste electrode (CPE) in various aquaeous Solution in the pH range of 0.5-12.30 by (CV) and osteryoung square wave voltammetry (OSWV). The best results were obtained for the quantitative determination of PAP by OSWV method in 0.5 mol L-1 Sulfuric acid at about pH 0.51. The peak current and peak potential depend on pH and scan rate were studied. The diffusion controlled nature of the peak was established. This electroanalytical procedure made it possible to determine PAP in the concentration range 2.5x10(-8)-2.5x10(-6) mol L-1. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 7.5x10(-9) and 2.5x10(-8) mol L-1 respectively. Precision and accuracy of the developed method were checked by recovery studies in spiked urine and tablet dosage forms.
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    Seasonal variation of some heavy metal pollution with environmental and microbiological parameters in sub-basin of Kocabas Stream (Biga, Canakkale, Turkey) by ICP-AES
    (Springer, 2007) Yayintas, Oezlem Tonguc; Yilmaz, Selahattin; Tuerkoglu, Muhammet; Colakoglu, Fatma Arik; Cakir, Fikret
    Waste water pollution in industrial areas is one of the most important environmental problems. Heavy metal pollution, especially chromium species in waste water sources from tannery affects our lives. Kocabas Stream is located in south-west Marmara region and Biga town is positioned in the sub basin on the stream. This water source functions as the water for irrigation in agriculture, drinking water for animals and for human use. Thus, this study is of great importance. Waste water pollution can affect all ecosystems and human health by directly or indirectly as in food chain. The concentration of heavy metals (Pb, Cd, Cu, Zn and Cr) were pre-analysed by ICP-AES method in water samples taken from sub-basin of Kocabas stream. In the results of these analyses, concentrations of the metals except chromium were founded at the limit value. But the total concentration of the Cr was found at high levels of between 0.0082 +/- 0.0001 and 5.7231 +/- 0.0921 mg l(-1) over the limit value (0.05 mg l(-1); WHO, EPA, TSE 266 and inland water quality classification) at sampling points very close to tannery factories. Also physicochemical and microbiological parameters of Kocabas Stream were determined. The effects of the experimental results on environment were investigated.
  • Küçük Resim
    Öğe
    The use of superporous p(3-acrylamidopropyl)trimethyl ammonium chloride cryogels for removal of toxic arsenate anions
    (Academic Press Ltd- Elsevier Science Ltd, 2015) Şahiner, Nurettin; Demirci, Şahin; Şahiner, Mehtap; Yilmaz, Selahattin; Al-Lohedan, Hamad
    Poly((3-Acrylamidopropyl)trimethylammonium chloride) (p(APTMACl)) cryogels were used as a superporous polymer network for the removal of toxic arsenate anions from an aqueous medium. The fast swelling in water, in about 7 s, was shown to be very useful leading to fast arsenate adsorption by p(APTMACl) cryogels within 30 min in comparison to 12 h for bulk common p(APTMACl) hydrogels. A maximum adsorption capacity of about 120 (mg/g) arsenate was obtained for p(APTMACl) cryogels. Both the Langmuir and Freundlich adsorption isotherms were applied for adsorption of arsenate anions by p(APTMACl) cryogels, and it was observed that the adsorption of arsenate anions by p(APTMACl) cryogels are represented better via Langmuir adsorption isotherm providing the R-2 value of 0.998. Furthermore, mag-p(APTMACl) cryogels were synthesized, and shown to be very useful in the fast removal of toxic arsenate anions. The mag-p(APTMACl) cryogels including the adsorbed arsenate were removed by an externally applied magnetic field, with some reduction in the arsenate ion adsorption capacity. It was also further demonstrated that p(APTMACl) cryogels can be reused in the adsorption of arsenate 5 times from aqueous environments without significant loss of adsorption capacity, from 113.47 +/- 9 to 102.67 +/- 6 mg/g. (C) 2015 Elsevier Ltd. All rights reserved.