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Öğe Anoxybacillus sp. SO B1-Immobilized Amberlite XAD-16 for Solid-Phase Preconcentration of Cu(II) and Pb(II) and Their Determinations by Flame Atomic Absorption Spectrometry(TAYLOR & FRANCIS INC, 2015) Oral, Elif Varhan; Ozdemir, Sadin; Dolak, Ibrahim; Okumus, Veysi; Dundar, Abdurrahman; Ziyadanogullari, Berrin; Aksoy, Zehra; Onat, RukenA new method for the determination of Cu(II) and Pb(II) by flame atomic absorption spectrometry (FAAS) after preconcentrating on a column containing Anoxybacillus sp. SO B1-immobilized Amberlite XAD-16 was developed. The functional groups of Anoxybacillus sp. SO B1 immobilized on Amberlite XAD-16 were characterized in KBr tablets by Fourier transform infrared (FT-IR) spectrometry. Various parameters such as pH, amount of the adsorbent, eluent type and volume, and flow rate of the sample solution were studied. The optimum pH values of quantitative sorption for Cu(II) and Pb(II) were found to be pH 7.0 and 5.0 and Cu(II) and Pb(II) ions could be quantitatively eluted with 5.0ml of 1.0mol L-1 HCI and 10.0ml of 0.25mol L-1 HNO3, respectively. Recoveries of Cu(II) and Pb(II) were found to be 100.9 +/- 1.57% and 100.3 +/- 0.49% (N = 5), the limits of detection of Cu(II) and Pb(II) in the determination by FAAS (3s, N = 10) were found to be 0.8 and 1.6 mu g L-1, respectively. The proposed enrichment method was applied for metal ion determination from water samples such as two parts of Tigris River water in Diyarbakir and Elazig, Lake of Hazar in Elazig, and tap water in Diyarbakir. Furthermore, the accuracy of the proposed method was verified by studying the analytical recovery and by analyzing certified reference material (NCS-DC 73350 leaves of poplar).Öğe Antioxidant Properties of Cultured Mycelia from Four Pleurotus Species Produced in Submerged Medium(TAYLOR & FRANCIS INC, 2013) Dundar, Abdurrahman; Okumus, Veysi; Ozdemir, Sadin; Yildiz, AbdunnasirThe ethanolic extracts of dried cultured mycelia of Pleurotus ostreatus, Pleurotus eryngii, Pleurotus florida, and Pleurotus sajor-caju were analyzed for antioxidant activity in different systems. Tests used are as follows: reducing power, free radical scavenging, superoxide anion radical scavenging, total antioxidant activity, metal chelating activitiy, etc.; total phenolic content was determined. The percentage inhibition of P. ostreatus, P. eryngii, P. florida, and P. sajor-caju at 20 mg/mL concentration on peroxidation in a -carotenelinoleic acid system was 57.19, 60.68, 62.12, and 58.81%, respectively. The reducing power of P. eryngii was higher than the other samples, and its value was 0.86 at 10 mg/mL concentration. P. ostreatus and P. sajor-caju proved to be better at scavenging superoxide anion radicals than the P. eryngii and P. florida. In the scavenging effect of DPPH radical test, P. ostreatus showed the highest activity potential and P. sajor-caju showed the strongest metal chelating capacity.Öğe Biosorption of chlorophenoxy acid herbicides from aqueous solution by using low-cost agricultural wastes(TAYLOR & FRANCIS INC, 2015) Okumus, Veysi; Celik, K. Serdar; Ozdemir, Sadin; Dundar, Abdurrahman; Kilinc, ErsinThe potential biosorption abilities of apple shell (AS), orange peel (OP), banana peel (BP), and millet waste (MW) as a bio-waste material to remove 2,4-dichlorophenoxy acetic acid (2,4-D), 2,4-dichlorophenoxy propanoic acid (2,4-DP), and 2,4-dichlorophenoxy butyric acid (2,4-DB) from aqueous solution were investigated in batch condition. Optimum biosorption conditions were determined as a function of contact time, pH of the solution, amount of biomass, and initial pesticide concentrations. The concentrations of the pesticides in the remaining solutions were simultaneously determined by high performance thin layer chromatography. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the pesticides by agricultural wastes. The experimental adsorption data were fitted to Langmuir adsorption models (r(2)>0.99). It was found that adsorption of 2,4-DP was higher for all biosorbent. The highest maximum adsorption capacities of 2,4-DP were found as 40.08, 22.71, 33.26, and 45.45mg/g, respectively, for AS, OP, BP, and MW. Maximum adsorption capacity was obtained for 2,4-D as OP>MW>BP>AS, 2,4-DP as MW>AS>BP>OP, and 2,4-DB as OP>AS>BP>MW. From the results, it can be said that MW was an effective biosorbent for removal of 2,4-DP and OP was an effective biosorbent for removal of 2,4-D and 2,4-DB through the studied pesticides. Optimum biosorption conditions were determined as 60min of contact time, 100mg of biomass, AS at pH 6.0, OP at pH 6.0, MW at pH 7.0, and BP at pH 7.0. FT-IR was employed to understand the surface properties of biosorbents. According to the results, agricultural wastes have high adsorption capacity.Öğe Comparative solid phase extraction study on the U(VI) preconcentration by using immobilized thermotolerant Bacillus vallismortis and Bacillus mojavensis(SPRINGER, 2018) Ozdemir, Sadin; Oduncu, M. Kadir; Kilinc, Ersin; Soylak, MustafaBacillus vallismortis and Bacillus mojavensis were loaded onto Amberlite XAD-4 resin and used for solid phase extraction (SPE) of uranium(VI). A quick and simple UV-Vis spectrophotometric method was used to determine U(VI) ion. The best experimental conditions were determined as being a pH of 5.0; a sample flow rate of 2.0 mL min(-1); 200.0 mg of biosorbent; 800 mg of Amberlite XAD-4, and 5.0 mL of 1 mol L-1 HCl as desorption solution for both immobilized bacteria. The preconcentration factors were achieved as 80 for both solid phase extractor. The developed methods were validated by applying to reference water and tea samples.Öğe Development of Armillae mellea immobilized nanodiamond for the preconcentrations of Cr(III), Hg(II) and Zn(II)(Analytical Biochemistry, 2021) Kılınç, Ersin; Ozdemir, Sadin; Şen, Fatih; Soylak, MustafaIn this study, we present an environmental friend and easy procedure for simultaneous preconcentration of Cr(III), Hg(II) and Zn(II) by solid-phase extraction before their determination by inductively coupled plasma optical emission spectrometry. Armillae mellea immobilized nanodiamond was used as sorbent. During the study, critical parameters influencing the extraction performance were investigated in detail. The best parameters were found as pH 5.0, 2.0 mL min−1 of flow rate, 200 mg of Armillae mellea, 300 mL of sample volume. LOD values were found as 0.025, 0.13 and 0.038 ng mL−1, respectively for Cr(III), Hg(II) and Zn(II). By applying the developed procedure, sensitivities of ICP-OES were improved for 60 fold for Cr(III), Hg(II) and Zn(II). Their concentrations in different food samples were measured after microwave digestion and solid-phase extraction.Öğe Magnetic solid phase extractions of Co(II) and Hg(II) by using magnetized C-micaceus from water and food samples(ELSEVIER SCI LTD, 2019) Ozdemir, Sadin; Mohamedsaid, Siham Abdullah; Kilinc, Ersin; Soylak, MustafaA new bio-MSPE sorbent based on the use of C. micaceus and gamma-Fe2O3 magnetic nanoparticle was prepared for the preconcentrations of Co(II) and Hg(II). Critical parameters including pH, flow rate, quantity of C. micaceus, quantity of gamma-Fe2O3 magnetic nanoparticle, eluent (type, concentration and volume), sample volume, and foreign ions were examined. Surface structure and variations after interaction with Co(II) and Hg(II) of bio-MSPE sorbent were investigated by FT-IR, SEM, and EDX. The impact of bio-MSPE column reusage was also tested. The biosorption capacities were determined as 24.7 mg g(-1) and 26.2 mg g(-1), respectively for Co(II) and Hg(II). Certified reference materials were utilized to find out the accuracy of the prepared bio-MSPE method. This novel bio-MSPE method was accomplished by being applied to real food and water samples. In particular, it will be possible to make use of C. micaceus as new alternatives, in environmental biotechnology applications.Öğe Metallo and metal free phthalocyanines bearing (4-(1(4-phenoxyphenyl)-1-phenylethyl)phenol substituents: Synthesis, characterization, aggregation behavior, electronic, antioxidant and antibacterial properties(ELSEVIER SCIENCE SA, 2014) Agirtas, M. Salih; Guven, M. Emin; Gumus, Selcuk; Ozdemir, Sadin; Dundar, AbdurrahmanAs starting material the phthalonitrile derivative bearing (4-(1(4-phenoxyphenyl)-1-phenylethyl)phenol substituents at peripheral position was prepared by a nucleophilic displacement reaction. Cyclotetramerization of 4-(4-(1-(4-hydroxyyphenyl)-1-phenylethyl)phenoxy)phthalonitrile derivative in the presence of corresponding metal salts gave the new metallophthalocyanines. Metal free phthalocyanine was obtained from the reaction of 4-(4-(1-(4-hydroxyyphenyl)-1-phenylethyl)phenoxy)phthalonitrile units. The novel compounds have been characterized by using various spectroscopic data. The aggregation investigations carried out in different concentrations indicate that 4-(4-(1-(4-hydroxyyphenyl)-1-phenylethyl)phenoxy)phthalocyanine compounds do not have any aggregation behavior for the concentration range of 10(-4)-10(-5) M in tetrahydrofuran. The antioxidant activities of novel compounds were analyzed through radical scavenging ability of 1,1-dipheny1-2-picrylhydrazyl, chelating ability to ferrous ions and reducing power. In addition to these, the antibacterial activities of compounds were investigated. Moreover, the ground-state geometries of the complexes were optimized using B3LYP/6-31G(d,p) level of density functional theory in order to predict the three-dimensional geometries and electronic structure. (C) 2014 Elsevier B.V. All rights reserved.Öğe Mononuclear Complexes Based on Pyrimidine Ring Azo Schiff-Base Ligand: Synthesis, Characterization, Antioxidant, Antibacterial, and Thermal Investigations(WILEY-V C H VERLAG GMBH, 2014) Gulcan, Mehmet; Ozdemir, Sadin; Dundar, Abdurrahman; Ispir, Esin; Kurtoglu, MukerremSix transition metal(II) complexes with the heterocyclic ligand HL (1), [CuL2]center dot H2O (2), [NiL2]center dot 3H(2)O (3), [CoL2]center dot 3H(2)O (4), [MnL2]center dot 3H(2)O (5), [ZnL2]center dot 2H(2)O (6), [PdLOAc]center dot H2O (7) [HL = 5-benzoyl-1-((E)-(2-hydroxy-5-((E)-phenyldiazenyl)benzylidene)amino)-4-phenylpyrimidin-2(1H)-one] were synthesized. The features of the azo Schiff bases were assigned from microanalytical, spectroscopic (IR, UV/Vis., H-1- and C-13 NMR, API-ES mass), magnetic, and molar conductivity measurements at room temperature as well as thermal analysis. The electronic absorption spectroscopy and magnetic susceptibility measurements of the complexes indicate square pyramidal arrangement for Pd-II and octahedral environment for all the other complexes. The azo Schiff base HL acts as a monobasic tridentate ligand, which commonly coordinates through the oxygen atoms of the phenol OH and the pyrimidine one group, and the nitrogen atom of the azomethine group. The thermal behaviors of the ligand and its metal complexes were studied using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The metal complexes proved to be more thermally stable than the ligand; they decomposed at 10-30 degrees C higher temperatures. Antioxidant properties of the ligand and its metal complexes (DPPH free radical scavenging, ferrous chelating and reducing power activities) were tested. Antimicrobial activities were studied with gram-positive bacteria, which included Bacillus subtilis and Staphylococcus aureus, whereas Escherichia coli and Pseudomonas aeruginosa represented gram negative bacteria.Öğe Preconcentration of metal ions using microbacteria(SPRINGER WIEN, 2013) Ozdemir, Sadin; Okumus, Veysi; Dundar, Abdurrahman; Kilinc, ErsinThis review (160 refs). covers the current state of the art of microbacteria-based sorbents for preconcentration of metal ions at trace levels. We highlight advantages and major challenges of the techniques and discuss future perspectives of both batch and column-based methods. Particular attention is paid to the preconcentration of metal ions using resin-immobilized microbacteria for solid phase extractions. We also discuss detection methods including UV-vis spectrophotometry, FAAS, ICP-OES and ICP-MS. Analytical figures of merit are compared, and examples are given for the application to a variety of samples including food, beverages, alloys, water, soil, and geological samples.Öğe Preconcentration of Sn in Real Water Samples by Solid Phase Extraction Based on the Use of Helvella leucopus as a Fungal Biomass Prior to its Determination by ICP-OES(ATOMIC SPECTROSCOPY, 2013) Kilinc, Ersin; Dundar, Abdurrahman; Ozdemir, Sadin; Okumus, VeysiRecently, biosorbents of biological origin such as fungus, algae, and bacteria have found special application as packing material in solid phase extraction (SPE). In this study, an alternative SPE method was developed and validated for the preconcentration of Sn prior to its determination by inductively coupled plasma optical emission spectrometry (ICP-OES). Helvella leucopus, a fungal biomass, was used as the biosorbent in the column studies. Experimental parameters, such as pH and flow rate of the solution, amounts of biosorbent and resin, and volume of the sample solution which affects the analytical results, were investigated. Effects of possible interfering ions on the SPE preconcentration of Sn were investigated. The sensitivity of ICP-OES was improved 47.1 times for Sn. The LOD and LOQ values were 0.06 and 0.21 ng respectively. Linearity was obtained in the concentration range of 1.0-30 ng mL(-1) for Sn. The loading capacity of Helvella leucopus immobilized Amberlite XAD-4 was 10.4 mg g(-1). The concentrations of Sn in the water samples from the Tigris River were determined using the developed method and validated by analysis of the certified reference material NWTM-26.3 Fortified Water sample.Öğe Preconcentration with Bacillus subtilis-Immobilized Amberlite XAD-16: Determination of Cu2+ and Ni2+ in River, Soil, and Vegetable Samples(TAYLOR & FRANCIS INC, 2015) Okumus, Veysi; Ozdemir, Sadin; Kilinc, Ersin; Dundar, Abdurrahman; Yuksel, Uyan; Baysal, ZubeydeSolid-phase extraction (SPE) method was developed for the preconcentration of Cu2+ and Ni2+ before their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). Bacillus subtilis-immobilized Amberlite XAD-16 was used as biosorbent. Effects of critical parameters such as pH, flow rate of samples, amount of Amberlite XAD-16 and biosorbent, sample volume, eluent type, and volume and concentration of eluent on column preconcentration of Cu2+ and Ni2+ were optimized. Applicability of the method was validated through the analysis of the certified reference tea sample (NCS ZC73014). Sensitivity of ICP-OES was improved by 36.4-fold for Cu2+ and 38.0-fold for Ni2+ by SPE-ICP-OES method. Limit of quantitation (LOQ) was found to be 0.7 and 1.1ng/ml for Cu2+ and Ni2+, respectively. Concentrations of Cu2+ and Ni2+ were determined by ICP-OES after application of developed method. Relative standard deviations (RSDs) were lower than 4.9% for Cu2+ and 7.9% for Ni2+. The Tigris River that irrigates a large agricultural part of Southeast Turkey is polluted by domestic and industrial wastes. Concentrations of Cu2+ and Ni2+ were determined in water, soil, and some edible vegetables as a biomonitor for heavy metal pollution.Öğe Preconcentrations and determinations of copper, nickel and lead in baby food samples employing Coprinus silvaticus immobilized multi-walled carbon nanotube as solid phase sorbent(ELSEVIER SCI LTD, 2019) Ozdemir, Sadin; Kilinc, Ersin; Oner, Ebru ToksoyPreconcentrations of Cu(II), Ni(II) and Pb(II) ions by using Coprinus silvaticus immobilized multiwalled carbon nanotube (MWCNT) were investigated. Effects of important parameters on preconcentration procedure were examined. The best pH values of for Cu(II), Ni(II) and Pb(II) were found to be 6.0, 6.0 and 4.0, respectively. Flow rate of sample solution was 2.0 mL min(-1), while desorption was achieved at 1.0 mL min(-1) flow rate. Preconcentration factors were achieved as 60 for Cu(II), Ni(II) and 70 for Pb(II) (by dividing initial sample volume to final volume). LODs were calculated as 0.014, 0.016 and 0.093 ng mL(-1), respectively for Cu(II), Ni(II) and Pb(II). Accuracy of the method was checked by applying to certified reference samples. Inductively coupled plasma optical emission spectrometer (ICP OES) was employed for measurements of Cu(II), Ni(II) and Pb(II) in digested baby food samples.Öğe Preconcentrations of Ni(II) and Co(II) by using immobilized thermophilic Geobacillus stearothermophilus eSO-20 before ICP-OES determinations(ELSEVIER SCI LTD, 2018) Yalcin, M. Serkan; Ozdemir, Sadin; Kilinc, ErsinThis study deals with the preconcentrations of Ni(II) and Co(II) ions in real samples using the solid phase extraction method (SPE) before their determinations by inductively coupled plasma optical emission spectrometry (ICP-OES). Thermophilic bacterium Geobacillus stearothermophilus SO-20 (Accession number: KJ095002), loaded with Amberlite XAD-4, was utilized as a novel biosorbent. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope (SEM) were employed for the investigation of the bacterial surface before and after Ni(II) and Co(II) biosorption. The experimental parameters were examined to find the best conditions. The retained Ni(II) and Co(II) ions on the biosorbent were eluted by using 5.0 ml of 1.0 mol l(-1) HCI as the best eluent. The sorption capacities were found to be 16.8 mg g(-1) for Ni(II) and 21.6 mg g(-1) for Co(II). It was also successfully used for the quantification of Ni(II) and Co(II) in a river water sample, some vegetables and soil.Öğe Preconcentrations of Pb(II), Ni(II) and Zn(II) by solid phase bio-extractor using thermophilic Bacillus subtilis loaded multiwalled carbon nanotube biosorbent(ScienceDirect, 2023) Ozdemir, Sadin; Dündar, Abdurrahman; Dizge, Nadir; Kılınç, Ersin; Balakrishnan, Deepanraj; Prasad, Kashi Sai; Senthilkumar, NatarajanAn alternative biotechnological solid phase bio-extraction (SPE) method was developed. Bacillus subtilis loaded multiwalled carbon nanotube was designed and used as biosorbent for the preconcentrations of Pb(II), Ni(II), and Zn(II). The experimental parameters such as sample flow rate, pH of sample solution, amounts of Bacillus subtilis and multiwalled carbon nanotube, volume of sample solution and reusability of column which affects the analytical characteristics of the SPE method were investigated in details. Surface structures were investigated by using FTIR, SEM. The best pH was determined as 5.0 and the percentages recoveries of Zn(II), Ni(II), and Pb(II) were determined as 99.1%, 98.7%, and 96.2%, respectively, at a flow rate of 3 mL/min. In this study, in which the profitable sample volume was determined as 400 mL and the amount of multiwalled carbon nanotube (MWCNT) as 50 mg. It was also observed that the column had a significant potential to preconcentrate Zn(II), Ni(II), and Pb(II) even after 25 reuses. The biosorption capacities for Pb(II), Ni(II) and Zn(II) were calculated as 34.2 mg/g, 36.8 mg/g and 45.5 mg/g respectively. The LOD values were calculated as 0.024 ng/mL for Pb(II), 0.029 ng/mL for Ni(II), and 0.019 ng/mL for Zn(II). The linear range was detected as 0.25–25 ng/mL. The concentrations of Pb(II), Ni(II), and Zn(II) in a variety of real food samples were determined by using developed method after application of certified reference sample.Öğe Production and characterization of thermostable alpha-amylase from thermophilic Anoxybacillus flavithermus sp nov SO-19(WILEY-V C H VERLAG GMBH, 2016) Ozdemir, Sadin; Okumus, Veysi; Ulutas, Mehmet Sefa; Dundar, Abdurrahman; Akarsubasic, Alper Tunga; Dumontet, StefanoThis study was concerned with isolation and identification of thermophilic bacteria from hot spring in Afyonkarahisar (Gecek) and optimization of a-amylase production, partial purification of alpha-amylase, and characterization of extracellular enzyme from isolated thermophilic strain 19. To characterize and identify the thermophilic isolated bacteria, morphological analysis and biochemistry tests were studied. Besides, for classification 16S rRNA gene, G-C content and DNA-DNA hybridization analysis were performed. These results indicated that strain 19 is a novel species, Anoxybacillus flavithermus sp. nov. The effects of different fermentation conditions, such as incubation time, temperature, and pH, different carbon and nitrogen sources, and surfactants on a-amylase production were investigated. Various parameters such as temperature and temperature stability, pH and pH stability, detergents and surfactants, different starches, and metal ions on influence of enzyme characterization were assayed. About 93, 87, and 81% of the activities were retained after heating the partially purified enzyme solution at 50, 60, and 70 for 240 min, respectively. Enzyme was excessively inhibited by Hg2+ (6%). The enzyme was activated by Co2+ (212%) and Mg2+ (142%). Enzyme degradated 82% of starch content in apple juice at 70 degrees C in 30 min. The molecular weight of enzyme was estimated as 96 kDa.Öğe Resistance, bioaccumulation and solid phase extraction of uranium (VI) by Bacillus vallismortis and its UV-vis spectrophotometric determination(ELSEVIER SCI LTD, 2017) Ozdemir, Sadin; Oduncu, M. Kadir; Kilinc, Ersin; Soylak, MustafaBioaccumulation, resistance and preconcentration of uranium(VI) by thermotolerant Bacillus vallismortis were investigated in details. The minimum inhibition concentration of (MIC) value of U(VI) was found as 85 mg/L and 15 mg/L in liquid and solid medium, respectively. Furthermore, the effect of various U(VI) concentrations on the growth of bacteria and bioaccumulation on B. vallismortis was examined in the liquid culture media. The growth was not significantly affected in the presence of 1.0, 2.5 and 5.0 mg/L U(VI) up to 72 h. The highest bioaccumulation value at 1 mg/L U(VI) concentration was detected at the 72nd hour (10 mg/g metal/dry bacteria), while the maximum bioaccumulation value at 5 mg/L U(VI) concentration was determined at the 48th hour (50 mg metal/dry bacteria). In addition to these, various concentration of U(VI) on alpha-amylase production was studied. The alpha-amylase activities at 0, 1, 2.5 and 5 mg/L U(VI) were found as 3313.2, 3845.2, 3687.1 and 3060.8 U/mg, respectively at 48th. Besides, uranium (VI) ions were preconcentrated with immobilized B. vallismortis onto multiwalled carbon nanotube (MWCNT) and were determined by UV-vis spectrophotometry. The surface macro structure and functionalities of B. vallismortis immobilized onto multiwalled carbon nanotube with and without U(VI) were examined by FT-IR and SEM. The optimum pH and flow rate for the biosorption of U(VI) were 4.0-5.0 and 1.0 mL/min, respectively. The quantitative elution occurred with 5.0 mL of 1 mol/L HCI. The loading capacity of immobilized B. vallismortis was determined as 23.6 mg/g. The certified reference sample was employed for the validation of developed solid phase extraction method. The new validated method was applied to the determination of U(VI) in water samples from Van Lake-Turkey. (C) 2017 Elsevier Ltd. All rights reserved.Öğe Selective preconcentration of Lanthanum(III) by Coriolus versicolor immobilised on Amberlite XAD-4 and its determination by ICP-OES(TAYLOR & FRANCIS LTD, 2014) Ozdemir, Sadin; Okumus, Veysi; Dundar, Abdurrahman; Celik, Kadir Serdar; Yuksel, Uyan; Kilinc, ErsinCoriolus versicolor, a wood fungus, was immobilised on Amberlite XAD-4 and used as solid-phase biosorbent for preconcentrations of rare earth elements. La(III), Th(IV), U(IV) and Ce(III) were subjected to solid-phase extraction procedure. We observed that La(III) was selectively preconcentrated, while other ions remained in solution at pH 6.0. 5.0mL of 1.0molL(-1) HCl was used to elaute La(III) from column. 250mg of C. versicolor loaded on 1000mg of XAD-4 was optimised as solid-phase matrix. Concentrations of ions in solutions were determined by inductively coupled plasma- optical emission spectrometry (ICP-OES). The calibration plot after preconcentration was linear in the range from 1.0 to 50.0ngmL(-1) for La(III). Limit of detection was found as 0.27ngmL(-1) for La(III) by SPE method. Relative standard deviation was found lower than 6.7% for 1.0ngmL(-1) of La(III) solution (n=10). The sensitivity of ICP-OES was improved by a factor of 46.8. The applicability of the method was validated through the analysis of certified reference samples of tea (NCS ZC-73014) and spinach (NCS ZC-73013).Öğe Simultaneous preconcentrations of Co2+, Cr6+, Hg2+ and Pb2+ ions by Bacillus altitudinis immobilized nanodiamond prior to their determinations in food samples by ICP-OES(ELSEVIER SCI LTD, 2017) Ozdemir, Sadin; Kilinc, Ersin; Celik, Kadir Serdar; Okumus, Veysi; Soylak, Mustafa; ;A novel solid phase extraction method was developed for simultaneous preconcentration-separation of Co2+, Cr6+, Hg2+ and Pb2+ ions prior to their determinations in food samples by ICP-OES. Thermophilic Bacillus altitudinis immobilized nanodiamond was used as a new biosorbent. SEM and FT-IR analysis were studied to characterize the biosorbent. The optimum pH values of quantitative biosorption for Co2+, Cr6+, Hg2+ and Pb2+ were found to be 5.0, 6.0, 6.0 and 6.0, respectively. A flow rate of 3.0 mL min(-1) was selected as optimum for all metal ions. 5 mL of 1 mol/L HCl was used as eluent. Preconcentration factor was achieved as 80. LODs were calculated as 0.071, 0.023, 0.016 and 0.034 ng mL(-1), respectively for Hg2+, Co2+, Cr6+ and Pb2+. The biosorption capacities were calculated for Co2+, Cr6+, Hg2+ and Pb2+ as 26.4, 30.4, 19.5, and 35.2 mg/g, respectively. The developed method was successfully applied to food samples to determine analyte concentrations. (C) 2016 Published by Elsevier Ltd.Öğe Thermophilic Geobacillus galactosidasius sp nov loaded gamma-Fe2O3 magnetic nanoparticle for the preconcentrations of Pb and Cd(ELSEVIER SCI LTD, 2016) Ozdemir, Sadin; Kilinc, Ersin; Okumus, Veysi; Poli, Annarita; Nicolaus, Barbara; Romano, IdaThermophilic bacteria, Geobacillus galactosidasius sp nov. was loaded on gamma-Fe2O3 magnetic nanoparticle for the preconcentrations of Pb and Cd by solid phase extraction before ICP-OES. pH and flow rate of the solution, amounts of biosorbent and magnetic nanoparticle, volume of sample solution, effects of the possible interferic ions were investigated in details. Linear calibration curves were constructed in the concentration ranges of 1.0-60 ng mL (1) for Pb and Cd. The RSDs of the method were lower than 2.8% for Pb and 3.8% for Cd. Certified and standard reference samples of fortified water, wastewater, poplar leaves, and simulated fresh water were used to accurate the method. LOD values were found as 0.07 and 0.06 ng mL (1) respectively for Pb and Cd. The biosorption capacities were found as 34.3 mg g (1) for Pb and 37.1 mg g (1) for Cd. Pb and Cd concentrations in foods were determined. Surface microstructure was investigated by SEM-EDX. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Tolerance and bioaccumulation of U(VI) by Bacillus mojavensis and its solid phase preconcentration by Bacillus mojavensis immobilized multiwalled carbon nanotube(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2017) Ozdemir, Sadin; Oduncu, M. Kadir; Kilinc, Ersin; Soylak, MustafaIn this study, uranium(VI) tolerance and bioaccumulation were investigated by using thermo-tolerant Bacillus mojavensis. The level of U(VI) was measured by UV-VIS spectrophotometry. The minimum inhibition concentration (MIC) value of U(VI) was experimented. Bacterial growth was not affected in the presence of 1.0 and 2.5 mg/L U(VI) at 36 h and the growth was partially affected in the presence of 5 mg/L U(VI) at 24 h. What was obtained from this study is that there was diversity in the various periods of the growth phases of metal bioaccumulation capacity, which was shown by B. mojavensis. The maximum bioaccumulation capacities were found to be 12.8, 22.7, and 48.2 mg/g dried bacteria, at 24th hours at concentration of 1.0, 2.5 and 5 mg/L U(VI), respectively. In addition to these, U(VI) has been pre-concentrated on B. mojavensis immobilized MWCNT. Several factors such as pH, flow rate of solution, amount of biosorbent and support materials, eluent type, concentration and volume, the matrix interference effect on retention have been studied, and extraction conditions were optimized. Preconcentration factor was achieved as 60. Under the optimized conditions, the limit of detection (LOD) and quantification (LOQ) were calculated as 0.74 and 2.47 mu g/L. The biosorption capacity of immobilized B. mojavensis was calculated for U(VI) as 25.8 mg/g. The results demonstrated that the immobilized biosorbent column could be reused at least 30 cycles of biosorption and desorption with the higher than 95% recovery. FT-IR and SEM analysis were performed to understand the surface properties of B. mojavensis. (C) 2016 Elsevier Ltd. All rights reserved.
