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Öğe Adsorption of Cu(II) onto silica gel-immobilized Schiff base derivative(ELSEVIER, 2009) Gübbük, I. Hilal; Gup, Ramazan; Kara, Huseyin; Ersöz, Mustafa4-chloroisonitroacetophenone 4-aminobenzylhydrazone (CAAH) chemically anchored on a silica gel surface, has been used for Cu(II) sorption from aqueous solution. The surface modification processes was performed after silanization of silica, then analyzed by elemental analysis, infrared spectroscopy, and thermogravimetry. The sorption behavior of copper(II) was evaluated by the use of batch and column methods. The influences of the concentration, temperature and pH for sorption on the immobilized silica gel with Schiff base were investigated. The obtained dynamic data were fitted to Freundlich, Langmuir and Dubinin-Raduskevich (D-R) isotherms. The mean sorption energy (E) of copper sorption onto silica gel was calculated from D-R isotherm indicating a chemical ion-exchange. The thermodynamic parameters such as Gibbs free energy change, enthalpy change and entropy change were calculated from the adsorption isotherms which were used to explain the mechanism of the adsorption. (C) 2009 Published by Elsevier B.V.Öğe 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, MustafaPresent 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.Öğe 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, SabaSingle 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.Öğe Central composite design and response surface methodology for the optimization of Ag+-HPLC/ELSD method for triglyceride profiling(SPRINGER, 2017) Arslan, Fatma Nur; Kara, HuseyinThe study presents the application of central composite design (CCD) and response surface methodology (RSM) for the optimization of silver-ion normal phase HPLC/ELSD (Ag+-HPLC/ELSD) method parameters to profile the isomers of triglycerides in vegetable oils. The significance of a second-order polynomial model for predicting the optimal values of Ag+-HPLC/ELSD method parameters was evaluated by the analysis of variance, ANOVA, and 3D response surface plots for the interactions between three variables were constructed. Three experimental parameters were chosen as independent variables which are the flow rate of mobile phase, temperature of column compartment and concentration of sample. A multivariate five-level CCD and RSM were used to confirm a quadratic model as a functional relationship between the response values (Rs, N, alpha and k') and variables. The optimum values of parameters were found to be a flow rate of 1.25 mL min(-1), temperature of column compartment of 20 A degrees C, and sample concentration of 5 x 10(-2) mg A mu L-1. Regression analysis with an R-2 values indicated as an adequate correlation between the experimental and predicted response values. ANOVA test results were also confirm that the models can be successfully used to predict the optimum parameters of Ag+-HPLC/ELSD method. Therefore, the proposed model provides an efficient, automated, and robust Ag+-HPLC/ELSD method for triglyceride profiling and is also suitable for a number of applications and analytical method developments for vegetable oils.Öğe Chemical Characterization of Canola and Sunflower Oil Deodorizer Distillates(INST ANIMAL REPRODUCTION & FOOD RESEARCH POLISH ACAD SCIENCES OLSZTYN, 2014) Naz, Saba; Sherazi, Syed Tufail Hussain; Talpur, Farah Naz; Kara, Huseyin; Uddin, Siraj; Khaskheli, Abdul RaufIn the present work deodorizer distillates of canola and sunflower oil were studied for their chemical characterization. Tocopherols, sterols, hydrocarbons and fatty acid composition were determined by Gas chromatography Mass spectrometry (GC-MS). Results indicated that deodorizer distillates of canola oil (DDCLO) studied had higher saponification value in the range of 164.2-175.8 mg/g and all deodorizer distillates of sunflower oil (DDSFO) had high iodine value of 126.2-127.1 g/100 g. Peroxide value and free fatty acids were present in the range between 7.0-8.9 mEq/Kg and 35.7-54.4 g/100 g in DDSFO and DDCLO samples, respectively. Contents of oleic acid (49.3-51.1 g/100 g) and linolenic acid (6.2-7.5 g/100 g) were significantly greater in DDCLO samples. Conversely, DDSFO contained concentrated amount of linoleic acid (52.8-53.3 g/100 g). Tocopherols and hydrocarbons were significantly higher in all DDSFO samples while, sterols were dominant in DDCLO samples. GC MS provided excellent results for simultaneous determination of tocopherols, sterols, hydrocarbons and fatty acid composition of deodorizer distillates of canola and sunflower oil.Öğe A Chemometric Approach to Assess the Frying Stability of Cottonseed Oil Blends During Deep-Frying Process: Fatty Acid Composition and Tocopherol Analyses(TAYLOR & FRANCIS INC, 2015) Arslan, Fatma Nur; Kara, Huseyin; Talpur, M. Younis; Sherazi, Syed Tufail HussainThe aim of the present study was to determine impacts of different additives on fatty acid composition and total tocopherol content of cottonseed oil during deep-frying process using a chemometric approach. A quarter-fractional factorial design with two levels and five factors was used for preparing the frying cottonseed oil blends. In the experimental design, additives were such as ascorbic palmitate, mixed tocopherols, dimethylpolysiloxane, lecithin, and sesame oil were used as factors. The effect of additives on fatty acid composition and tocopherol content were evaluated with normal distribution (ND) graphs during ten hours frying at 170 +/- 5 degrees C. The data were statistically assessed by one-way analysis of variance at a significance level of p < 0.05. The analysis of variance test results were in good agreement with ND graphs and data indicated that the interaction between ascorbic palmitate and dimethylpolysiloxane (A x C factor) showed a significant and protective effect on fatty acids. Meanwhile, the sesame oil (E factor) and A x C factor were showed a significant effect on level of tocopherols. The results of study indicated that present approach could be used to assess and improve the frying stability of any oil with respect to fatty acid composition and tocopherols.Öğe 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, AdnanThe 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.Öğe A chemometric study: Automated flow injection analysis method for the quantitative determination of humic acid in Ilgm lignite(ELSEVIER SCIENCE BV, 2016) Tarhan, Ismail; Kara, HuseyinA rapid, sensitive and provident flow injection analysis (FIA) method was developed within the framework of a chemometric approach for the quantification of humic acid (HA) in the lignite obtained from Ilgm, Konya, Turkey. The proposed method allows automatic determination of 60 samples per hour over a wide calibration range (0-2000 mg L-1, R-2: 0.9988) and needs only 10 mu L of sample at a flow rate of mobile phase (X-1), 2 mL min(-1); pH of mobile phase (X-2), 8, and system temperature (X-3), 20 degrees C. The limits of detection (LOD) and quantification (LOQ) were calculated as 9.18 mg L-1 and 30.60 mg L-1, respectively, and the relative standard deviation (RSD) for 500 mg L-1 HA was calculated as 3.44 (n: 9). It was revealed that the standard deviation (SD) values of the proposed FIA method are lower than those of the spectrophotometric method. (C) 2014 King Saud University. Production and hosting by Elsevier B.V.Öğe Copper sorption efficiency of p-tetranitrocalix[4]arene based high performance liquid chromatographic column(DESALINATION PUBL, 2016) Durmaz, Fatih; Memon, Fakhar N.; Memon, Shahabuddin; Memon, Ayaz A.; Memon, Naeem A.; Kara, HuseyinPresent study deals with the sorption characteristics of p-tetranitrocalix[4]arene (3) appended silica-based high-performance liquid chromatographic (HPLC) column utilized for preconcentration, determination, and purification of Cu2+ from water. The sorption characteristics of the HPLC column were investigated for Cu2+ in column agreement. The experiments were performed in five steps that were monitored using UV-visible diode-array detector. However, all the HPLC experimental results were reconfirmed by using atomic absorption spectrophotometer. The effect of concentration on the sorption efficiency of the column was evaluated for Cu2+ and data obtained was investigated using Langmuir and Freundlich sorption isotherms. The value of coefficient of determination (R-2), i.e. 0.99, suggested that the Freundlich sorption isotherm was found to be the best fit model for Cu2+. The developed method was validated for system efficiency, accuracy, and precision, while the data obtained revealed that the developed column could be applied for the sorption of Cu2+ with adequate efficiency and repeatability.Öğe DETERMINATION OF DEFENSIN HNP-1 IN HUMAN SALIVA OF PATIENTS WITH ORAL MUCOSAL DISEASES(TAYLOR & FRANCIS INC, 2011) Kucukkolbasi, Hasan; Kucukkolbasi, Semahat; Dursun, Recep; Ayyildiz, Filiz; Kara, HuseyinSaliva is a biological fluid that is easily obtainable and that can give useful information both in systemic and oral diseases. In this study, a chromatographic method was applied to determine the amount of defensin HNP-1 in human saliva of patients with oral mucosal diseases before and after treatments and compared with controls. Defensin human neutrophil peptide-1 (HNP-1) was identified and confirmed. The concentration of HNP-1 in saliva was determined by comparing the area of eluted HNP-1 with that of HNP-1 standard. Linear calibration range of defensin HNP-1 was 0.10 to 0.90 mu g/10 mu L with R(2) values of 0.996. The concentrations of HNP-1 in the saliva of patients with oral lichen planus, Behcet's disease, and recurrent apthous stomatitis were 33.6 +/- 10.6, 15.5 +/- 7.6, and 36.3 +/- 9.5 mu gmL(-1) (mean +/- S.D.), respectively. The salivary defensin-1 concentration was significantly higher in patients with oral mucosal diseases than in healthy volunteers; furthermore, in patients with oral mucosal diseases, the concentration was significantly higher before treatment than after treatment.Öğe Determination of Ochratoxin A in Poultry Feed by High-Performance Liquid Chromatography with a Monolithic Column(TAYLOR & FRANCIS INC, 2015) Shar, Zahid Hussain; Sumbal, Gul Ameer; Sherazi, Syed Tufail Hussain; Kara, Huseyin; Hussain, Masood; Bhanger, Muhammad IqbalA monolithic column with high-performance liquid chromatography coupled with an ultraviolet detector was investigated for the determination of ochratoxin A in poultry feed. A systematic study was performed using solid phase extraction with a C-18 cartridge for sample pretreatment with three solvent systems. Ethyl acetate:methanol:formic acid (95:5:0.5) was found to be the most suitable. Pretreated samples were injected separately into packed and monolithic columns. The effects of the mobile phases on the chromatographic figures of merits were evaluated. Better peak symmetry, improved separation, and more theoretical plates were observed using an acetonitrile:water:formic acid (99:99:2) mobile phase. The repeatability and accuracy of the method were statistically evaluated and found to be satisfactory with a limit of detection of 40 mu gL(-1). The use of a monolithic column in conjunction with sample pretreatment provided good results for the determination of ochratoxin A in poultry feed.Öğe Determination of Unsaponifiable Constituents of Deodorizer Distillates by GC-MS(SPRINGER, 2012) Naz, Saba; Sherazi, S. T. H.; Talpur, Farah N.; Talpur, M. Younis; Kara, HuseyinDeodorizer distillate is an important by-product obtained during deodorization in the edible oil industries. It is a complex mixture of many health beneficial constituents like phytosterols, tocopherols and squalene. In the present study a simple gas chromatographic method with mass spectrometry was used for the separation, detection and quantification of different components present in the deodorizer distillate in a very short analysis time of 18 min. A simple saponification procedure without derivatization was used for their analysis followed by GC-MS analysis. Phytosterols concentration (21.27-25.53%) was the most abundant in canola and palm distillate samples whereas, squalene and tocopherol were present in concentration ranges of 2.89-13.21% and 1.29-5.81%, respectively. The present study revealed that the unsaponifiable fraction of deodorizer distillate could be used in cosmetic preparations due to its appreciable amount of bioactive constituents.Öğe 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 HussainPresent 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.Öğe 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 HussainTriglyceride 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.Öğe Fully Automated Three-Dimensional Column-Switching SPE-FIA-HPLC System for the Characterization of Lipids by a Single Injection: Part I. Instrumental Design and Chemometric Approach to Assess the Effect of Experimental Settings on the Response of ELSD(SPRINGER, 2016) Arslan, Fatma Nur; Kara, HuseyinThis article presents the first application of fully automated three-dimensional (3D) column-switching SPE-FIA-HPLC system for the characterization of lipids by a single injection. The whole system was designed and set up by modifying Agilent 1200 Series HPLC system in our laboratory. By using this system, a complete separation profile of the oil samples was achieved in a very short time period by using single injections. This approach was applied on vegetable oils which contains a large number of relatively high-class lipid components, such as TG, FFA, sterols, tocopherols, DG, ester and MG. In this part of the study, we focused on the optimization of evaporative light scattering detector (ELSD) by using an experimental design and RSM. Three experimental parameters were chosen as an independent variables which are the flow rate of mobile phase, nebulization temperature and evaporation temperature. A multivariate five level experimental design was used to establish a quadratic model as a functional relationship between the response values and independent variables. The optimal values of parameters were found to be a flow rate of 1.25 mL min(-1), nebulization temperature of 80 degrees C, and evaporation temperature of 40 degrees C. Regression analysis with an R-2 values indicated as a satisfactory correlation between the experimental and predicted values. ANOVA test results were also illustrate that the models can be successfully used to predict the optimum parameters of ELSD. Thus, the proposed system is suitable for a large number of applications including research and development of new quality control and characterization methods for vegetable oils.Öğe A green approach for the production of biodiesel from fatty acids of corn deodorizer distillate(ROYAL SOC CHEMISTRY, 2014) Naz, Saba; Kara, Huseyin; Sherazi, Syed Tufail Hussain; Aljabour, Abdalaziz; Talpur, Farah NazA novel alginic acid derived tin catalyst, tin alginate (Sn-Alg), was successfully synthesized, characterized and applied for methyl esterification. Initially, the amount of catalyst, methanol to fatty acid ratio and reaction time were optimized using an oleic acid standard for esterification. The optimal reaction conditions were found to be 4% catalyst, 1 : 12 oleic acid to methanol mole ratio and 2 h reaction time with 98.7% fatty acid methyl ester recovery. The capability of Sn-Alg beads to esterify the fatty acids of corn deodorizer distillate was evaluated. High recovery (97.6%) of esters was obtained after 8 cycles using reprocessed catalyst under the optimized parameters. The results of the present study indicated that based on the environmental pollution, reusability, avoiding the use of potassium or sodium hydroxides or sulphuric or phosphoric acids, and ease of catalyst separation, the solid Sn-Alg catalyst has a great potential for biodiesel production from highly free fatty acid deodorizer distillates.Öğe A Highly Efficient Automated Flow Injection Method for Rapid Determination of Free Fatty Acid Content in Corn Oils(SPRINGER, 2014) Ayyildiz, H. Filiz; Kara, HuseyinIn the present study, a new flow injection (FI) methodology for determination of free fatty acid (FFA) content in corn oil samples is proposed. The proposed method is based on monitoring the absorbance changes at 580 nm, lambda (max), as a result of neutralization of FFA in oil samples by KOH in the reagent. The analyses were performed with a single-line FI manifold system created by modification of high performance liquid chromatography. The main parameters, such as sample and reagent volumes, reaction coil, reagent concentration and temperature were all optimized. With the newly developed sampling strategy, the oil sample and reagent at micro level were directly injected together without any pre-treatment. The proposed flow injection analysis method was validated statistically and it was found to be linear (between 0.09 and 1.50 FFA %), accurate (recovery 87.19-122.22 %), and precise (relative standard deviation < 1 % for both intra-day and inter-day precision). The limit of detection and limit of quantification were found to be 7.41 x 10(-3) and 2.24 x 10(-2) oleic acid %, respectively. The results were also compared with those obtained by the American Oil Chemists Society (Ca-5a-40) method using statistical t and F tests, and a significant difference was not observed between the methods at the 95 % confidence level. These results strongly suggest that this method is suitable for automated routine analysis of FFA in edible oils due to its simplicity, reliability, speed, and economy of solvents and sample.Öğe Investigating sorption characteristics of copper ions onto insolubilized humic acid by using a continuously monitored solid phase extraction technique(ELSEVIER SCIENCE BV, 2007) Gezici, Orhan; Kara, Huseyin; Yanik, Sema; Ayyildiz, H. Filiz; Kucukkolbasi, SemahatThe sorption characteristics of Cu(II) in an insolubilized humic acid (IHA) mediated column system were investigated at various experimental conditions using a solid phase extraction (SPE) technique. Sodium form of the IHA (INaA) was used as solid phase and sorption behaviors were evaluated by using common adsorption isotherms as well as Scatchard plot analysis. Regeneration, loading, washing and stripping steps of SPE were carried out consecutively, and their progresses were monitored through breakthrough curves obtained from a continuous flow-through cell adapted UV-vis spectrophotometer. So, the breakthrough curves were used to visualize distribution of Cu(II) concentration between mobile phase and solid phase, and amount of the Cu(II) sorbed by INaA was obtained from AAS analysis of effluents collected during the stripping steps of particular run. Thus, from the obtained results, the sorption characteristics and usability of IHA as a solid phase for SPE of metal ions was evaluated in detail. (c) 2007 Elsevier B.V. All rights reserved.Öğe Investigation of synthesis of copolymers from the waste products of industrial oil refinement having adhesion properties and strength to the thermal destruction(SPRINGER/PLENUM PUBLISHERS, 2006) Yazicigil, Zafer; Ahmetli, Gulnare; Kara, Huseyin; Kocak, AhmetIn this study, the waste products of industrial vegetable oil refinement were transformed into the glycidyl ester for preventing the effects of them to the environment, the ways for evaluating them in polymer chemistry were investigated, copolymers having high adhesion property and strength to the thermal destruction were synthesized and the area of their usage was determined. For this reason, the waste product of sunflower oil refination as a vegetable oil in the industry; soap stock (SS) was converted to the unsaturated glycidyl esters by the interaction with epichlorohidrine in the alkaline medium. After that the copolymerization of synthesized unsaturated glycidyl esters and the other waste product of oil refinement fatty acid (FA) with styrene in the radicalic initiator medium were investigated and copolymers that have high strength to the thermal destruction and adhesion property were synthesized. From the results of TGA and DTA analysis, it was determined that synthesized copolymers have low loss of weight at high temperature. The structures of copolymers were fixed by spectral and chemical analysis methods.Öğe Monitoring of Zn(II), Cd(II), Pb(II) and Cu(II) During Refining of Some Vegetable Oils Using Differential Pulse Anodic Stripping Voltammetry(SPRINGER, 2014) Kucukkolbasi, Semahat; Temur, Osman; Kara, Huseyin; Khaskheli, Abdul RaufIn this study, a novel approach has been developed using differential pulse anodic stripping voltammetry (DPASV) for the simultaneous determination of Zn(II), Cd(II), Pb(II) and Cu(II) in edible oils at hanging mercury drop electrode. The microwave digestion of oil samples was carried out with concentrated HNO3 and H2O2. KNO3 was used as a supporting electrolyte. The experimental conditions optimized such as deposition time, stirring rate and size of mercury drop were 300 s, 600 rpm and 10 mm(2), respectively. The method was applied to quantify Zn(II), Cd(II), Pb(II) and Cu(II) in crude and refined hazelnut, corn, sunflower and olive oils. During refining of different vegetable oils, the removal efficiencies of Zn(II), Cd(II), Pb(II) and Cu(II) were calculated as 98.20-99.91, 98.50-99.90, 95.26-99.76 and 95.93-99.92 %, respectively. The limits of detection for Zn(II), Cd(II), Pb(II) and Cu(II) were 2.1x10(-8), 8.7x10(-10), 7.1x10(-9) and 3.4x10(-9) and the limits of quantification were 6.8x10(-8), 2.9x10(-9), 2.3x10(-8) and 1.1x10(-8) M with linear regression coefficients (R-2) of 0.9930, 0.9928, 0.9893 and 0.9931, respectively. It was observed that the above metals in crude and refined vegetable oils could be determined simultaneously by the DPASV method.
