Yazar "Topkafa, Mustafa" seçeneğine göre listele

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    Application of central composite design for the optimization of on-line solid phase extraction of Cu-2 (+) by calix[4]arene bonded silica resin
    (ELSEVIER SCIENCE BV, 2015) Memon, Fakhar N.; Ayyilidiz, H. Filiz; Kara, Huseyin; Memon, Shahabuddin; Kenar, Adnan; Leghari, Muhammad Khan; Topkafa, Mustafa
    Present study deals with the optimization of on-line solid phase extraction of Cu2+ using calix[4]arene based silica resin by the assessment of central composite design of response surface methodology. The immobilized resin was characterized with FT-IR and SEM techniques. The data obtained from experimental program of central composite design was used to model the parameters that significantly affect on Cu2+ extraction. The variables chosen were metal ion concentration, pH, and temperature. Second-order quadratic model was used to approximate the effect of variables on extraction efficiency. Furthermore, suggested model was also validated with the analysis of variance. The predicted values were in good agreement with experimental results, suggesting proficient application of central composite design as an economical alternative to acquire maximum amount of information for the modeling of on-line solid phase extraction with little number of experiments. Additionally, data obtained for different concentrations was analyzed by Freundlich, Langmuir, D-R isotherms, and Scatchard plot analysis. The results suggested that Langmuir isotherm was best fit model with R-2 0.99, the energy calculated from D-R isotherm was 15.14 KJ/mol suggesting that chemical force is involved in sorption process. The method was also validated for its linearity, accuracy, and precision. (C) 2015 Elsevier B.V. All rights reserved.
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    Application of multivariate chemometric techniques for simultaneous determination of five parameters of cottonseed oil by single bounce attenuated total reflectance Fourier transform infrared spectroscopy
    (ELSEVIER, 2014) Talpur, M. Younis; Kara, Huseyin; Sherazi, S. T. H.; Ayyildiz, H. Filiz; Topkafa, Mustafa; Arslan, Fatma Nur; Naz, Saba
    Single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy in conjunction with chemometrics was used for accurate determination of free fatty acid (FFA), peroxide value (PV), iodine value (IV), conjugated diene (CD) and conjugated triene (CT) of cottonseed oil (CSO) during potato chips frying. Partial least square (PLS), stepwise multiple linear regression (SMLR), principal component regression (PCR) and simple Beer's law (SBL) were applied to develop the calibrations for simultaneous evaluation of five stated parameters of cottonseed oil (CSO) during frying of French frozen potato chips at 170 degrees C. Good regression coefficients (R-2) were achieved for FFA, PV, IV, CD and CT with value of > 0.992 by PLS, SMLR, PCR, and SBL. Root mean square error of prediction (RMSEP) was found to be less than 1.95% for all determinations. Result of the study indicated that SB-ATR FTIR in combination with multivariate chemometrics could be used for accurate and simultaneous determination of different parameters during the frying process without using any toxic organic solvent. (C) 2014 Elsevier B.V. All rights reserved.
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    A Chemometric Approach to Assess the Frying Stability of Cottonseed Oil Blends During Deep-Frying Process: I. Polar and Polymeric Compound Analyses
    (WILEY, 2013) Arslan, Fatma Nur; Kara, Huseyin; Ayyildiz, Hamide Filiz; Topkafa, Mustafa; Tarhan, Ismail; Kenar, Adnan
    The main goal of the present study was (i) to determine the formation of degradation products in cottonseed oil (CSO) blends during deep frying process by adsorption and high performance size exclusion chromatography techniques and (ii) to evaluate the impacts of food additives on total polar (TPC) and polymeric compound (PTAG) formation using a chemometric approach. In order to prepare the frying CSO blends; ascorbic palmitate, mixed tocopherols, dimethylpolysiloxane, lecithin and sesame oils were used as additives. To determine the real impacts of additives, a quarter-fraction factorial experimental design with two levels and five factors was used. The changes in TPC and PTAG data were carefully evaluated during 10 h of frying at 170 +/- A 5 A degrees C with normal distribution (ND) graphs and analyzed using a one-way analysis of variance (ANOVA), followed by Tukey's Post-hoc test (alpha = 0.05). The results indicated that the increasing values for TPC and PTAG during the frying processes for all blends, TPC and PTAG contents reached maximum levels of 16.37 and 6.01 % respectively, which are below the limit values stated by official authorities for the quality assessment of frying oils. The ANOVA test results were in good agreement with ND graphs and data indicated that the impact of mixed tocopherols was significant for TPC formation, meanwhile the impact of lecithin and ascorbic palmitate x dimethylpolysiloxane were significant for PTAG formation. Thus, the present study should be considered to be a very useful guide for developing new frying oil formulations based on CSO by using food additives.
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    Evaluation of Aflatoxin B1 Binding Capacity with Mix Toxin Binder using Central Composite Design
    (Selçuk Üniversitesi, 2024 Nisan) Yalçın, Nihayet Fadime; Cantekin, Cafer; Uğuz, Halis; Alataş, Mustafa Selçuk; Sherazi, Syed Tufail Hussain; Topkafa, Mustafa
    Aflatoxin B1 (afl B1) binding capacity of a mixed toxin binder used in poultry nutrition was determined using the central composite design technique. Experimental conditions such as pH, temperature, and incubation time for the determination of the binding capacity of the mixed binder were optimized for Central Composite Design. The impact of these three independent variables on the percentage binding of aflatoxin B1 was evaluated at different five levels (-1.68, -1, 0, 1, 1.68). The optimum experimental conditions were 5.8 pH, 42°C temperature, and 94.11 minutes incubation time, respectively, using a quadratic model and desirability function. A significant effect of each independent variable was observed on the percentage binding efficiency of aflatoxin B1. Under optimum experimental conditions, aflatoxin B1 binding capacity with mix toxin binder was found to be 97%. The results of the present study indicated that the mixed binder is very suitable for binding aflatoxin B1 and the central composite design can be used effectively in determining the optimized parameters for improving toxin binding capacity of aflatoxin B1.
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    Evaluation of chemical properties of cold pressed onion, okra, rosehip, safflower and carrot seed oils: triglyceride, fatty acid and tocol compositions
    (ROYAL SOC CHEMISTRY, 2016) Topkafa, Mustafa
    Chemical properties of cold pressed onion (OnSO), okra (OkSO), rosehip (RSE), safflower (SSO) and carrot (CSO) seed oils were evaluated in terms of triglyceride (TG), fatty acid and tocol (tocopherol and tocotrienol) compositions. Cold pressed OnSO, OkSO, RSO, and SSO had high amounts of OLL, PLL, LLLn and LLL triglycerides, respectively, whereas cold pressed CSO had a significant amount of OOL triglyceride. Monounsaturated fatty acids (MUFAs) were dominant in CSO with 81.8%, while polyunsaturated fatty acids (PUFAs) were dominant in OnSO, OkSO, RSE, and SSO oils at 58.7%, 47.9%, 74.1% and 73.8%, respectively. The highest total tocol content was in OnSO (2608.8 mg kg(-1)), followed by RSO (1124.2 mg kg(-1)), OkSO (716.7 mg kg(-1)), SSO (417.5 mg kg(-1)) and CSO (258.0 mg kg(-1)) seed oils. There was a positive association between total tocopherol and PUFA and between total tocotrienol and MUFA.
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    Evaluation of Fatty Acid Composition, Tocols Profile, and Oxidative Stability of Some Fully Refined Edible Oils
    (TAYLOR & FRANCIS INC, 2015) Ayyildiz, Hamide Filiz; Topkafa, Mustafa; Kara, Huseyin; Sherazi, Syed Tufail Hussain
    Present study includes evaluation of fatty acid composition, tocols profile, and oxidative stability of some fully refined edible oils. Fully refined sunflower, soybean, corn, hazelnut, peanut, and canola oils were analyzed for fatty acids by capillary gas liquid chromatography, tocols by normal phase-high performance liquid chromatography and oxidative stability by rancimat. Free fatty acid, peroxide value, and iodine value of investigated oils were determined by titrimetric methods. Saturated, mono-, and polyunsaturated fatty acids were found to be in the ranges between 2.03-18.58, 23.39-77.26, and 14.39-58.52%, respectively. Tocols and oxidative stability of the investigated oils were found to be in the ranges between 488.88-913.51 mg kg(-1) and 3.05-4.99 h, respectively.
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    Evaluation of the Triglyceride Composition of Pomegranate Seed Oil by RP-HPLC Followed by GC-MS
    (SPRINGER, 2015) Topkafa, Mustafa; Kara, Huseyin; Sherazi, Syed Tufail Hussain
    Triglyceride composition and fatty acid profiles of pomegranate seed oil were evaluated by newly developed methods in reverse-phase-high performance liquid chromatography (RP-HPLC) and gas chromatography (GC), respectively. Different compositions of the mobile phase (acetone and acetonitrile) and flow rates for the HPLC system were used to obtain better separation for accurate quantitative analysis. Triglycerides with conjugated fatty acids (CLnAs) were eluted in order of the polarity of their geometrical isomers (c, t, c < t, t, c < t, t, t). The dominant triglyceride was found to be PuPuPu (32.99 %) in pomegranate seed oil, followed by PuPuCa and PuCaCa containing punicic acid and catalpic acid with total triglyceridelevels of 27.72 and 10.11 %, respectively. For fatty acid composition analysis, triglyceride fractions were derivatized into their respective methylesters which were injected into gas chromatography-mass spectrometry (GC-MS) to identify and gas chromatography-flame ionization detector (GC-FID) to quantify the conjugated fatty acids of each fraction of triglycerides. Punicic acid was found to be dominant (76.57 %) followed by catalpic acid (6.47 %) and beta-eleotearic acid (1.45 %). Pomegranate seed contained greater amounts of conjugated linolenic acids. These results showed that the present study provides more information about the composition of the triglyceride and fatty acid profiles of pomegranate seed oil compared to the reported studies. Therefore, the developed methods in this study can be used for the identification of the triglyceride and fatty acid composition for pomegranate seed oils and some such specials edible oils including CLnA isomers.
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    İmmobilize hümik asitlerin katı faz ekstraksiyon sistemlerinde kullanımı
    (Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2006-12-22) Topkafa, Mustafa; Kara, Hüseyin
    Doğal olarak oluşmuş, çok çeşitli fonksiyonel gruplara sahip hümik asitlerin, sulu ortamlarda metal iyonlarını tutabilme ve düşük pH`larda bırakabilme özelliği, metal iyonlarının uzaklaştırılması, geri kazanılması ve zenginleştirilmesi için çok uygun bir yöntem olan katı faz ektraksiyonu (SPE) sistemlerinde etkin bir madde olarak kullanılabilmesini sağlamıştır. Hümik asitlerin pH>3 olan sulu çözeltilerde az veya çok çözünmesi, bu maddelerin doğrudan adsorban olarak kullanılmalarını kısıtlamakta ve bu maddeler ancak çözünürsüzleştirme ve immobilizasyon gibi çeşitli işlemlerden geçirildikten sonra iyon değiştirici/adsorban madde olarak SPE sistemlerinde kullanılabilmektedir. Sunulan bu çalışmada; aminopropil silika (APS) üzerine immobilizasyonu yapılan ve pH 10`a kadar çözünme kararlılığı sağlanan hümik asit sabit faz olarak kullanılmış ve Cu, Ni, Co iyonlarının tutulma özelliklerine besleme çözeltisinin pH`sının ve konsantrasyonunun etkisi incelenmiştir. Deneylerde Cu tuzlarının tutulma etkilerini incelemek için Cu(NO3)2, Cu(CH3COO)2 ve CuNa2Y tuzları kullanılmıştır. Cu(II), Ni(II) ve Co(II) iyonlarının SPE işlemleri ImNaA ile doldurulmuş bir kolonda yürütülmüş ve sürekli sistemden elde edilen ?breakthrough eğrileri? ile işlemler takip edilmiştir. Cu(II), Ni(II) ve Co(II) iyonlarının her üçü için de, besleme çözeltisinin konsantrasyonu ve pH'sı attıkça, ImNaA tarafından tutulan miktarlarında da bir artış gözlenmiştir. Cu(II) ve Ni(II) iyonları Langmuir, Co (II)iyonlarının ise hem Freundlich hemde Langmuir izotermlerine uyan tutulma davranışı sergilediği gözlenmiştir. Sorpsiyonun mekanizmasını incelemek için Dubinin-Radushkevich adsorpsiyon izotermleri çıkarılmış ve ortalama adsorpsiyon enerjisi Cu(II), Ni(II) ve Co(II) iyonlarının için sırasıyla; 17,68kJ/mol, 26,73 kJ/mol ve 40,82 kJ/mol olarak hesaplanmıştır. Scatchard eğri analizleri ile izotermlerin uygunluluğu irdelenmiştir. Scatchard eğri analizinden iki doğru elde edilmiştir. Bu doğrulardan yüksek ve düşük enerjili etkileşimlerle tutunmanın gerçekleştiği görülmüştür. Adsorpsiyon izotermlerinden, Cu(II) ve Ni(II)'nin ağırlıklı olarak kimyasal etkileşmelerle ve Co(II)'nin ise hem fiziksel hemde kimyasal etkileşmeler ile tutulduğu sonucuna varılmıştır. SPE işlemlerinin sürekli olarak gözlenmesi için HPLC sistemi kullanılmıştır. Sonuç olarak; SPE işlemlerinde sabit faz olarak ImNaA'nın verimli olduğu ve kromatografik analizlerde sabit faz olarak kullanılabilirliğinin uygun olduğu görülmüştür.
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    An implementation of central composite design: Effect of microwave and conventional heating techniques on the triglyceride composition and trans isomer formation in corn oil
    (TAYLOR & FRANCIS INC, 2017) Topkafa, Mustafa; Ayyildiz, Hamide Filiz
    Triglyceride composition and trans fatty acid content of corn oil subjected to microwave and conventional heating were evaluated with the aid of central composite design methodology. Oil samples with and without alpha-tocopherol were prepared on the basis of central composite design and, the effects of the main three factors (temperature, contact time, and the amount of alpha-tocopherol) were tired to investigate 10 at different five levels. Linoleic acid-linoleic acid-linoleic acid content in triglyceride structure of corn oil and the amount of trans fatty acids in the same oils were taken as response values for evaluation of central composite design assays. Based on the response surface, the optimum conditions (at which trans fatty acid formation and the change in the triglyceride composition are minimum) were determined for both heating procedures. The results showed that the increasing of the temperature and contact time increased the trans fatty acid formation and changed triglyceride structure of the oil in both heating techniques, although, the addition of alpha-tocopherol at high concentration caused pro-oxidant effect on triglyceride composition (bad effect), while reducing the formation of trans fatty acid (good effect). The results revealed that the heating 20 treatments caused significant changes in the triglyceride composition and trans fatty acid isomers of unsaturated fatty acids of the oil, while the saturated fatty acid contents did not change substantially. These alterations were much greater in microwave-heated samples (trans fatty acid <= 7.26%) than in Q3 corresponding samples heated in a conventional stove (trans fatty acid <= 0.56%).
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    New potential humic acid stationary phase toward drug components: Development of a chemometric-assisted RP-HPLC method for the determination of paracetamol and caffeine in tablet formulations
    (WILEY-V C H VERLAG GMBH, 2016) Topkafa, Mustafa; Ayyildiz, Hamide Filiz; Memon, Fakhar N.; Kara, Huseyin
    A new humic acid based stationary phase has been used, for the first time, to achieve the separation and quantification of paracetamol and caffeine in pharmaceutical preparations under reversed-phase high-performance liquid chromatography conditions. Central composite design was applied as a powerful tool to optimize the most dominant parameters that influence the resolution of reversed-phase high-performance liquid chromatography, that is, mobile phase composition (acetonitrile percentage in water), flow rate, and column temperature. The optimum conditions were obtained as 21.69%, 1.5 mL/min, and 15 degrees C, respectively, with the aid of a second-order quadratic model and desirability function. Under the optimum conditions, the peaks could be baseline separated within 10 min. For the developed reversed-phase high-performance liquid chromatography method, the linearity was investigated in the concentration ranges of 2-160 mg/mL (R-2 = 0.999) for paracetamol and 2-9.9 mg/mL (R-2 = 0.991) for caffeine. Mean recoveries for paracetamol and caffeine were 95.90 and 95.68%, respectively. The limits of detection and quantification were 4.1 x 10(-4) and 1.3 x 10(-3) mg/mL for paracetamol and 1.6 x 10(-4) and 5.0 x 10(-4) mg/mL for caffeine. The results showed that the new humic acid based stationary phase is very suitable for the separation of paracetamol and caffeine in pharmaceutical preparations and, thus it can be used effectively in the pharmaceutical industry.
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    Polarographic and voltammetric determination of trace amounts of 2-aminoanthraquinone
    (POLSKIE TOWARZYSTWO CHEMICZNE-POLISH CHEMICAL SOC, 2007) Peckova, Karolina; FiizAyyidjz, Hamide; Topkafa, Mustafa; Kara, Huseyin; Ersöz, Mustafa; Barek, Jiri
    2-Aminoanthraquinone (2-AA) is a genotoxic intermediate in the industrial synthesis of anthraquinone dyes. In this work, electroanalytical methods based on two-electron reduction of anthraquinone at mercury electrodes were developed for determination of microto nanomolar concentrations of this analyte in mixed aqueous-methanol media. Calibration plots obtained for differential pulse voltammetry and direct current voltammetry at a hanging mercury drop electrode exhibited a sigmoidal shape within the analyte's concentration range of (1-500) x 10(-7) mol L-1, presumably because of strong adsorption of the analyte at the electrode surface. Linearity of the calibration plots was achieved for higher concentrations of 2-AA at a conventional dropping mercury electrode using DC tast polarography and differential pulse polarography, with limit of quantitation of 4 x 10(-6) mol L-1 in Britton-Robinson buffer (pH 6)-methanol mixture (1: 1). Adsorption of 2-AA on the electrode surface enabled its determination at nanomolar concentrations (limit of quantitation 2.8 x 10(-9) mol L-1) using cathodic adsorptive stripping voltammetry in Britton-Robinson buffer (pH 2)-methanol mixture (99: 1).
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    Removal and Preconcentration of Cobalt Ions from Aqueous Media Using ImHA Packed Column by On-Line SPE System
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2012) Ayyildiz, H. Filiz; Topkafa, Mustafa; Arslan, FatmaNur; Durmaz, Fatih; Kucukkolbasi, Semahat; Tarhan, Ismail; Kara, Huseyin
    This work assesses the use of immobilized humic acid (ImHA) onto aminopropyl silica (APS) as a sorbent for the removal and preconcentration of trace amounts of cobalt ions by on-line solid phase extraction (SPE) technique in the column system prepared in our laboratory. Different parameters, such as the effect of the pH, concentration, and flow rate, were studied and throughput was observed by a UV detector. All SPE steps were monitored by breakthrough curves used to visualize distribution of cobalt concentration between mobile and solid phase. The solutions collected from stripping steps were analyzed in atomic absorption spectrometer (AAS) and the amount of sorbed ions was calculated. Sorption characteristics were evaluated by using common adsorption isotherms and Scatchard plot analysis. From the obtained results, it was seen that sorption mechanism of cobalt ions were fitted to Langmuir model on a large scale and thought to be localized. Mean free energy (E = 40.82 kJ mol(-1)) calculated from D-R isotherm showed that chemical interactions are more effective than physical interactions. This investigation reveals a new, simple, environmentally friendly, and cost-effective method for removal and preconcentration of cobalt ions from aqueous solutions by a new aminopropyl silica-immobilized humic acid material.
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    Role of Different Bleaching Earths for Sunflower Oil in a Pilot Plant Bleaching System
    (DE GRUYTER OPEN LTD, 2013) Topkafa, Mustafa; Ayyildiz, H. Filiz; Arslan, Fatma Nur; Kucukkolbasi, Semahat; Durmaz, Fatih; Sen, Seyit; Kara, Huseyin
    The purpose of present study is to investigate the efficiency of different kinds of Turkish commercial bleaching earth materials for changes in different colour pigment concentrations in neutralized sunflower oils. The bleaching experiments were performed in a pilot system under at stable vacuum (50 mmHg) and temperature (100 degrees C) for 30 min. By examining the changes in chlorophyll, beta-carotene and red colour, bleaching process parameters such as type and dosage of the bleaching material were optimised. The sorption characteristics of colour pigments were evaluated using common adsorption isotherms and Scatchard plot analysis. Ads-3 acid-activated earth material at 1% (w/w) per samples was found to be the most appropriate sorbent and the amount of sorbed pigments was calculated as 1.01x10(-4)mmol/g ads. for chlorophyll, 1.15x10(-3)mmol/g ads. for carotene and 1.70 red on Lovibond colour scale. The procedure indicated that this system can be easily adapted to the actual oil refining systems.
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    Sorption behavior of Cu(II) ions on insolubilized humic acid under acidic conditions: An application of Scatchard plot analysis in evaluating the pH dependence of specific and nonspecific bindings
    (ELSEVIER SCIENCE BV, 2007) Gezici, Orhan; Kara, Huseyin; Ayar, Ahmet; Topkafa, Mustafa
    Sorption behavior of Cu(II) ions on a humic acid-based solid phase, insolubilized humic acid (IHA), were investigated under continuous column conditions. The quantitative data were derived on the basis of breakthrough curves obtained at different experimental conditions. For the studied experimental conditions, the highest and lowest observable capacities of IHA toward Cu(II) were found as 48.34 and 0.84 mu mol g(-1), respectively. In order to evaluate the pH dependence of Cu(II) binding on IHA, the effect of influent concentration was investigated at three different pH values (1.0, 2.0 and 3.0), and adsorption isotherms were derived for each acidic condition. The characteristics of Cu(II) bindings were evaluated by using Scatchard plot analysis, and it was observed that under strongly acidic condition, pH 1.0, nonspecific and/or multi-type interactions between Cu(II) and MA were the prevailing effects causing the Cu(II) sorption. On the other hand, at pH 2.0 and 3.0, the role of specific interactions was more clearly observed, and so at pH(s) 2.0 and 3.0, the binding of Cu(II) on IHA was mainly attributed to specific interactions rather than nonspecific ones. For pH 2.0 and 3.0, the binding types of Cu(II) on IHA were sub-classified according to different affinities observed between Cu(II) and IHA, and thus two main types of specific bindings were proposed for the studied influent concentration range (1.0 x 10(-3) to 1.0 X 10(-1) mol l(-1)): Type-1, high-affinity/low capacity and Type-2, low-affinity/high capacity bindings. Finally, probable benefit of each specific binding type in separation of Cu(II) from acidic aqueous media has been discussed in detail. (c) 2006 Elsevier B.V. All rights reserved.
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    Use of aminoprophyl silica-immobilized humic acid for Cu(II) ions removal from aqueous solution by using a continuously monitored solid phase extraction technique in a column arrangement
    (ELSEVIER SCIENCE BV, 2008) Kara, Huseyin; Ayyildiz, H. Filiz; Topkafa, Mustafa
    Humic acid (HA) which originated from Leonardite was purified and immobilized onto aminoprophyl silica (APS). Afterwards, the remaining amino groups on the silica are successfully end-capped using acetic anhydride in DMF media and this material was used for Cu(II) ions removal from aqueous solution by using continuously solid phase extraction (SPE) technique in a column arrangement. The sorption characteristics of Cu(II)-immobilized humic acid (ImHA) system were investigated at various experimental conditions, and output was observed by a UV detector. All solid phase extraction (SPE) steps were monitored through breakthrough curves used to visualize distribution of Cu(II) concentration between mobile phase and solid phase. In addition to this, the solutions collected from stripping steps were analyzed in atomic absorption spectrophotometry (AAS) and the amount of adsorbed Cu(II) ions was calculated. It was found that there was a high correlation (R-2 = 1) between the peak area and AAS data of stripping steps. Sorption characteristics were evaluated by using Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) adsorption isotherms, as well as by Scatchard plot analysis. Thus, the sorption characteristics and usability of ImHA as a solid phase for SPE of Cu(II) ions was evaluated in detail. From the obtained results, it was seen that sorption mechanism of Cu(II) fits to Langmuir model on a large scale, sorption was thought to be localized. From D-R isotherm mean free energy of sorption (E) was calculated (17.68 kJ mol(-1)), and it was deduced that chemical interactions were more effective than physical interactions for Cu(II). This investigation provides a new, environmentally friendly and cost-effective possibility to remove Cu(II) ions from aqueous solution by using the new APS-ImHA material. (c) 2007 Elsevier B.V. All rights reserved.
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    Yenilebilir nar çekirdeği yağının rafinasyon özelliklerinin incelenmesi
    (Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2013-09-05) Topkafa, Mustafa; Kara, Hüseyin
    Bu tez çalışmasında; yüksek konjuge linolenik asit içeriğiyle (~%80) yağlı çekirdek tohumları arasında oldukça önemli bir yere sahip olan, fakat şimdiye kadar yemeklik yağ olarak üretimi yapılmamış ve rafinasyon özellikleri hiç incelenmemiş nar çekirdeği yağının temel özelliklerinin ve rafinasyon boyunca yağda meydana gelen fiziksel & kimyasal değişiklikler ortaya çıkartılarak rafinasyon şartlarının tespit edilmesi amaçlanmıştır. Rafinasyon süresince nar çekirdeği yağında meydana gelen değişiklerin gözlenmesi amacıyla gerçekleştirilen yağ asit kompozisyonu, sterol, wax, polar ve polimerik madde, vitamin & tokoferol-tokotrienol, trigliserit, antioksidan kapasitesi, spektrofotometrik FTIR ve TGA/DTG analizlerinin yürütülmesinde; literatürde yer alan metotların yanı sıra, nar çekirdeği yağı ve bu tür özel yağlar için kullanılmak üzere tarafımızdan geliştirilen yeni metotlar da kullanılmıştır. Araştırma bulguları, nar çekirdeği yağının vitamin, tokoferol-tokotrienol, sterol, wax ve antioksidan içeriğinin rafinasyon prosesi boyunca azaldığını, yağ asit kompozisyonu, polar ve polimerik madde miktarı, trigliserit düzeyi, spektrofotometrik FTIR ve TGA/DTG özelliklerinin de proses parametrelerine bağlı olarak değişime uğradığını göstermiştir. Ayrıca; konjuge linolenik yağ asidi içeriği bakımından özel bir yere sahip olan nar çekirdeği yağının rafinasyonu sırasında yağ asitlerinin önemli ölçüde izomerizasyona uğradığı da tespit edilmiş, elde edilen değerler trigliserit analizi ile doğrulanmıştır. Nar çekirdeği yağının yapısında meydana gelen fiziksel & kimyasal değişikliklere ilişkin elde edilen değerler, bir yemeklik yağın sahip olması gereken sınır değerler arasında yer almakta olup; gerçekleştirilen rafinasyon prosesinin istenilen seviyede ve doğrulukta yapıldığının bir göstergesi olarak; rafine nar çekirdeği yağının polimerik madde içeriği: % 6.18, wax miktarı: 24 ppm, klorofil miktarı: 0.012 ppm, tokoferol-tokotrienol içeriği: 700 ppm, sterol içeriği: 4313 ppm ve ß-karoten içeriği: 0.747 ppm olarak tespit edilmiştir. Seçkin tat ve kararlılığa, yüksek miktarda konjuge linolenik asit, vitamin ve tokoferol-tokotrienol içeriğine sahip, diğer bitkisel yağlardan kolaylıkla ayırt edilebilen özellikte ve hastalıklardan korunmada ideal bir yağ olan nar çekirdeği yağının yüksek kalitede rafinasyonu ile ülkemiz ve dünya gıda sektöründe yemeklik yağ olarak kullanılması umut edilmektedir