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Öğe Anoxybacillus sp. SO B1 immobilized Amberlite XAD-16 for solid phase preconcentration of Cu(II), Pb(II) and their determinations by flame atomic absorption spectrometry(Bioremediation Journal, 2016) Varhan, Elif; Özdemir, Sadin; Dolak, İbrahim; Okumuş, Veysi; Dündar, Abdurrahman; Ziyadanoğulları, 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 5.0 ml of 1.0 mol L¡1 HCI and 10.0 ml of 0.25 mol 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 D 5), the limits of detection of Cu(II) and Pb(II) in the determination by FAAS (3 s, N D 10) were found to be 0.8 and 1.6 mg 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 Diyarbakır and Elazı_g, Lake of Hazar in Elazı_g, and tap water in Diyarbakır. 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.(International Journal of Food Properties, 2013) Dündar, Abdurrahman; Okumuş, Veysi; Özdemir, Sadin; Yıldız, AbdulnasırThe 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 β-carotene–linoleic 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 Antioxidant properties, chemical composition and nutritional value of terfezia boudieri (Chatin) from Turkey.(Food Science and Technology International, 2012) Dündar, Abdurrahman; Yeşil, Ömer Faruk; Acay, Hilal; Okumuş, Veysi; Özdemir, Sadin; Yıldız, AbdulnasırOur objectives were to investigate the chemical composition, nutritive value and antioxidant activity potentials of Terfezia boudieri Chatin collected from different areas from Southeast of Turkey. The amounts of energy, protein, fat, carbohydrate, crude fibre, moisture and ash were 34.00–65.00 (kcal/100 g), 1.40–2.73, 0.86–1.71, 4.84–11.60, 80.86–90.33 (g/100 g, f.w.) and 1.02–1.98 g/100 g dry mass, respectively. Fatty acids and amino acids analyses revealed that linoleic acid and glutamic acid were, respectively the most abundant. Among the essential amino acids leucine was the highest amount and this was followed by threonine. Magnesium was the most abundant element with a concentration value of 182.30 mg/100 g dry mass. T. boudieri exhibited excellent antioxidant activity when compared with standard compounds. In total antioxidant and chelating effect on ferrous ions activity T. boudieri showed the highest activity against the standards. Additionally, at all studied tests antioxidant activity of the mushroom increased with increasing concentration. The total phenolic content of T. boudieri was found as 8.45 mg/g.Öğe Biosorption of 2,4-D, 2,4-DP and 2,4-DB from aqueous solution by using thermophilic anoxybacillus flavitermus and analysis by high performance thin layer chromatography: equilibrium and kinetic studies(Environmental Progress & Sustainable Energy, 2012) Özdemir, Sadin; Matpan, Fatma; Okumuş, Veysi; Dündar, Abdurrahman; Kılınç, ErsinIn this study, the potential biosorption characteristics of the thermophilic Anoxybacillus flavithermus (A. flavithermus) was investigated for the removal of the chlorophenoxy acid derivates, namely, 2,4-dichlorophenoxy acetic acid (2,4-D), 2,4-dichlorophenoxy propanoic acid (2,4-DP or dichlorprop), and 2,4-dichlorophenoxy butyric acid (2,4-DB). The experiments were performed for the simultaneous biosorption of the studied pesticides. Optimum biosorption conditions were determined as a function of contact time, pH of the solution, amount of biomass, and initial pesticides concentrations. The concentrations of the pesticides in the remaining solutions were simultaneously analyzed by high performance thin layer chromatography. The optimum parameters were found as pH: 4.0 for biosorption medium, 60 min of contact time, 50 mg of bacteria, and 50 mg L21 of initial pesticides concentrations. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the pesticides by A. flavithermus as biomass. Biosorption of pesticides on to A. flavithermus showed pseudo first-order rate kinetics at different initial concentration of pesticides and different temperatures. The experimental adsorption data were fitted both the Langmuir and Freundlich adsorption models. Fourier-transform Infrared spectroscopy was used to understand the bonding mechanism of pesticides to biosorbent and surface functionality of the biosorbent The highest pesticide uptake was calculated from Langmuir isotherm and found to be 24.15 mg/g for 2,4-D Among the studied pesticides, 2,4-DP showed difference adsorption behavior. According to in your comments the reason of this that 2,4-DP contain an asymmetric carbon atom, which provide a molecular chirality.Öğe Biosorption of chlorophenoxy acid herbicides from aqueous solution by using low-cost agricultural wastes.(Desalination and Water Treatment, 2015) Okumuş, Veysi; Çelik, Kadir; Özdemir, Sadin; Dündar, Abdurrahman; Kılınç, 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 (r2 > 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 45.45 mg/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 60 min of contact time, 100 mg 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 DNA cleavage properties and synthesis of metallophthalocyanines with 5-methyl-[1, 2, 4] triazolo [1, 5-a] pyrimidin-7-oxy substituents.(Inorganic and Nano-Metal Chemistry, 2017) Ağırtaş, Salih; Öndeş, Yusuf; Özdemir, Sadin; Okumuş, VeysiThe aim of the present study is to perform synthesis of novel metallophthalocyanines (pcs) with high solubility. The synthesis and characterization of 5-methyl-[1, 2, 4] triazolo [1, 5-a] pyrimidin-7-yloxysubstituted zinc, magnesium, and cobalt pcs are reported. These compounds have been characterized using electronic absorption, nuclear magnetic resonance spectroscopy, infrared, elemental analysis and mass spectra. The aggregation investigations carried out in different concentrations indicate that 5- methyl-[1, 2, 4] triazolo [1, 5-a] pyrimidin-7-yloxy-substituted pc complexes do not have any aggregation behavior for the concentration range of 1 £ 10¡5¡1 £ 10¡6 M in THF. DPPH radical scavenging activity, metal chelating activity, and reducing power of the compounds were evaluated. The DNA gel electrophoresis studies revealed that new phthalonitrile and its metallophthalocyanine compounds cleavaged plasmid DNA (pBR322). Additionally, the ground-state geometries of the complexes were optimized using density functional theory methods at B3LYP/6-31G (d, p) level in order to obtain information about the 3D geometries and electronic structure.Öğe Isolation a thermophilic anoxybacillus flavithermus sp. nov. and production of thermostable α-amylase under solid-state fermentation (SSF)(Annals of Microbiology, 2012) Özdemir, Sadin; Matpan, Fatma; Okumuş, Veysi; Dündar, Abdurrahman; Ulutaş, Sefa; Kumru, MertA new bacteria was isolated from hot-spring water of Gazlıgöl, Afyonkarahisar in Turkey. Based on morphological and biochemical tests and 16S rRNA gene sequence analysis, the isolate belonged to the Anoxybacillus flavithermus species which has 99% similarity with the bacterium DNA. The production of α-amylase by thermophilic Anoxybacillus flavithermus was investigated under solid-state fermentation by using some agricultural waste as substrates. Solid substrates such as rice husk, banana husk, millet, water melon husk, lentil bran, wheat bran and maize oil cake were studied for enzyme production. Of these, rice husk was proved as the best substrate for α-amylase production (1,271 U/mg). The maximum α-amylase production was observed as 1,803 U/mg at 72 h, 1,000 μm particle size, 70% initial moisture content (w/v), and 40% inoculum level (v/w). Among the various nitrogen sources tested, 1% peptone (3,170 U/mg) was found to be the best nitrogen source for α-amylase production. As additional carbon sources, 1% starch (2,364 U/mg) enhanced α-amylase production. The optimum temperature for the activity of α-amylase was found to be 70°C. The enzyme was optimally active at pH 6.0 and stable in the pH range of 6.0–8.0.Öğe Metallo phthalocyanines bearing (2-((2-hydroxyethyl) (p-tolyl)amino)ethoxy) and (2-((2-phenoxyethyl) (p-tolyl)amino)ethoxy) phthalonitrile substituents: Synthesis, characterization, aggregation behavior, antioxidant and antibacterial activity(Synthetic Metals, 2014) Çelebi, Metin; Ağırtaş, Salih; Özdemir, Sadin; Okumuş, VeysitThe novel phthalonitrile derivatives bearing (2-((2-hydroxyethyl)(p-tolyl)amino)ethoxy) and (2-((2-phenoxyethyl)(p-tolyl)amino)ethoxy)phthalonitrile substituents at peripheral position were preparedby a nucleophilic displacement reaction. Cyclotetramerization of these phthalonitrile derivatives in thepresence of corresponding metal salts gave the new metallophthalocyanines. The novel compounds werecharacterized by using various spectroscopic data. The aggregation investigations carried out in differ-ent concentrations indicate that phthalocyanine compounds do not have any aggregation behavior forthe concentration range of 10−4–10−6M in tetrahydrofuran. In vitro three antioxidant test methods,namely diphenylpicrylhydrazyl radical scavenging activity, metal chelating activity and reducing powerwere used to determine the antioxidant activity of compounds. Compounds were analyzed for theirantibacterial activity against some bacteria by using the disk-diffusion method.Öğe New water soluble phenoxy phenyl diazenyl benzoic acid substituted phthalocyanine derivatives: Synthesis, antioxidant activities, atypical aggregation behavior and electronic properties.(Dyes and Pigments, 2013) Ağırtaş, Salih; Çelebi, Metin; Gümüş, Selçuk; Özdemir, Sadin; Okumuş, VeysiNovel substituted phthalonitrile derivatives were obtained by the reaction of 2-(4-hydroxyphenylazo) benzoic acid and 4,5-dichloro-1,2-dicyanobenzene, or 4-nitrophthalonitrile. Peripherally phenoxy phenyl diazenyl benzoic acid substituted zinc (II) phthalocyanine complexes, and their sodium salts were synthesized and characterized for the first time. The newly synthesized phthalocyanine complexes show excellent solubility in water. The aggregation investigations carried out in different concentrations indicate that phenoxy phenyl diazenyl benzoic acid-substituted phthalocyanine compounds do not have any aggregation behavior for the concentration range of 7.00 _ 10_5e4.38 _ 10_6 M in DMF. The antioxidant activities of DMF solution of compounds were analyzed through radical scavenging, and chelating ability to Fe2ş cation. Additionally, new compounds did not show any antibacterial activity against some selected bacteria cultures. Moreover, the ground-state geometries of the complexes were optimized using density functional theory (DFT) methods at B3LYP/6-31G(d,p) level in order to obtain information about the 3D geometries and electronic structure.Öğe Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent for preconcentrations of Cd2 and Co2 and their determination by ICP-OES(Elsevier B.V., 2012) Özdemir, Sadin; Okumuş, Veysi; Klnç, Ersin; Bilgetekin, Havin; Dündar, Abdurrahman; Ziyadanogullar, BerrinThis article reports a method that is used for the preconcentration and determination of Cd2 and Co2 in vegetables, using Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent. The concentrations of metals were determined by inductively coupled plasma-optical spectrometry (ICP-OES). Critical parameters, such as the pH of the solution, flow rate, the amount of biosorbent, type and volume of eluent, and the sample volume, that affect the solid-phase extraction (SPE) procedure were optimized. The optimum extraction conditions were determined as being a pH of 6.0 for Cd2 and of 5.0 for Co2; a sample flow rate of 2.0 mL min-1; 200.0 mg of biosorbent; and 5.0 mL of 1.0 mol L-1 HCl as eluent. The capacities of the biosorbent for metal uptake were found to be 11.3 and 9.8 mg g-1 for Cd2 and Co2 ions, respectively. Limit of quantitations (LOQs) were found to be 0.67 and 0.82 ng mL-1, respectively, for Cd2 and Co2. The linear working curves were observed to be in the linear range from 1.0 to 50.0 ng mL-1, and possessed high correlation coefficients. The use of the SPE method showed 50.7- and 35.7-fold improvements in the sensitivities of ICP-OES. The developed method was successfully applied to NCS ZC-73014 (a certified reference tea sample). Relative standard deviations (RSD) were lower than 5.0%. The Cd2 and Co2 concentrations in the different parts (leave, root, stem, and fruit) of purslane, onion, rocket, okra, and aubergine were determined after microwave digestion and solid-phase extraction by P. eryngii immobilized on Amberlite XAD-16. © 2012 Elsevier B.V.Öğe Pleurotus eryngii immobilized amberlite XAD-16 as a solid-phase biosorbent for preconcentrations of Cd2+ and Co2+ and their determination by ICP-OES(Talanta, 2012) Özdemir, Sadin; Okumuş, Veysi; Kılınç, Ersin; Bilgetekin, Havin; Dündar, Abdurrahman; Ziyadanoğulları, BerrinThis article reports a method that is used for the preconcentration and determination of Cd and Co in vegetables, using Pleurotus eryngii immobilized Amberlite XAD-16 as a solid-phase biosorbent. The concentrations of metals were determined by inductively coupled plasma-optical spectrometry (ICP-OES). Critical parameters, such as the pH of the solution, flow rate, the amount of biosorbent, type and volume of eluent, and the sample volume, that affect the solid-phase extraction (SPE) procedure were optimized. The optimum extraction conditions were determined as being a pH of 6.0 for Cd and of 5.0 for Co; a sample flow rate of 2.0 mL min_1; 200.0 mg of biosorbent; and 5.0 mL of 1.0 mol L_1 HCl as eluent. The capacities of the biosorbent for metal uptake were found to be 11.3 and 9.8 mg g_1 for Cd and Co ions, respectively. Limit of quantitations (LOQs) were found to be 0.67 and 0.82 ng mL_1, respectively, for Cd and Co. The linear working curves were observed to be in the linear range from 1.0 to 50.0 ng mL_1, and possessed high correlation coefficients. The use of the SPE method showed 50.7- and 35.7-fold improvements in the sensitivities of ICP-OES. The developed method was successfully applied to NCS ZC-73014 (a certified reference tea sample). Relative standard deviations (RSD) were lower than 5.0%. The Cdand Co concentrations in the different parts (leave, root, stem, and fruit) of purslane, onion, rocket, okra, and aubergine were determined after microwave digestion and solid-phase extraction by P. eryngii immobilized on Amberlite XAD-16.Öğe Preconcentration of metal ions using microbacteria(Microchimica Acta, 2013) Özdemir, Sadin; Okumuş, Veysi; Dündar, Abdurrahman; Kılınç, 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 resinimmobilized 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) Kılınç, Ersin; Dündar, Abdurrahman; Özdemir, Sadin; Okumuş, 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 (ICPOES). 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 mL-1, 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 g 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: determinations of cu2+ and ni2+ in river, soil, and vegetable samples(Bioremediation Journal, 2015) Okumuş, Veysi; Özdemir, Sadin; Kılınç, Ersin; Dündar, Abdurrahman; Yüksel, Uyan; Baysal, ZübeydeSolid-phase extraction (SPE) method was developed for the preconcentration of Cu and Ni 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 Cu and Ni 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 Cu2C and 38.0-fold for Ni2C by SPE-ICP-OES method. Limit of quantitation (LOQ) was found to be 0.7 and 1.1 ng/ml for Cu2C and Ni2C, respectively. Concentrations of Cu and Ni were determined by ICP-OES after application of developed method. Relative standard deviations (RSDs) were lower than 4.9% for Cu and 7.9% for Ni. The Tigris River that irrigates a large agricultural part of Southeast Turkey is polluted by domestic and industrial wastes. Concentrations of Cu and Ni were determined in water, soil, and some edible vegetables as a biomonitor for heavy metal pollution.Öğe Production and characterization of thermostable α-amylase from thermophilic anoxybacillus flavithermus sp. nov. SO-19.(Starch, 2016) Özdemir, Sadin; Okumuş, Veysi; Ulutaş, Sefa; Dündar, Abdurrahman; Akarsubaşı, Alpertunga; Dumonted, 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 a-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, pHand 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 Hg (6%). The enzyme was activated by Co (212%) and Mg (142%). Enzyme degradated 82% of starch content in apple juice at70°C in 30 min. The molecular weight of enzyme was estimated as 96 kDa.Öğe Selective preconcentration of lanthanum (III) by coriolus versicolor immobilized on amberlite XAD-4 and its determination by ICP-OES.(International Journal of Environmental Analytical Chemistry, 2014) Özdemir, Sadin; Okumuş, Veysi; Dündar, Abdurrahman; Çelik, Kadir; Yüksel, Uyan; Kılınç, 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. 5.0 mL of 1.0 mol L−1 HCl was used to elaute La(III) from column. 250 mg of C. versicolor loaded on 1000 mg 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 50.0 ng mL−1 for La(III). Limit of detection was found as 0.27 ng mL−1 for La(III) by SPE method. Relative standard deviation was found lower than 6.7% for 1.0 ng mL−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 ıcp-oes.(Food Chemistry, 2017) Özdemir, Sadin; Kılınç, Ersin; Okumuş, Veysi; Çelik, Kadir; Soylak, MustafaCo2+, 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.Öğe Solid phase extraction based on the use of agaricus arvensis as a fungal biomass for the preconcentrations of Pb and Al prior to their determination in vegetables by ICP-OES.(Atomic Spectroscopy, 2013) Kılınç, Ersin; Dündar, Abdurrahman; Özdemir, Sadin; Okumuş, VeysiA solid phase extraction (SPE) method based on the use of a fungal biomass as sorbent was developed for the preconcentrations of Pb and Al. Agaricus arvensis was immobilized on Amberlite XAD-4 and loaded onto a column. Important parameters such as pH and flow rate of the solution, amount of biosorbent and resin, volume of sample solution, which affect the efficiency of the preconcentration procedure for Pb and Al, were optimized. The effect of possible interfering ions, i.e., Cd2+, Cu2+, Ni2+, Zn2+, Co2+, Na+, K+, Ca2+, Mg2+, and Fe2+, was investigated. Experiments on the repeatability of the solid phase column showed that the same column could be used at least 30 cycles without loss of the biosorption efficiency for the recovery of Pb and Al. The limit of detection (LOD) of Pb and Al was found to be 0.10 ng mL-1 and 0.03 ng mL-1, respectively. The sensitivity of ICP-OES improved 39.8-fold for Pb and 39.5-fold for Al. Linearity was obtained in the concentration range of 1.25–50.0 ng mL-1 for Pb and 0.5–50.0 ng mL-1 for Al. The relative standard deviation (RSD) of the method under optimum conditions was lower than 8.4% (n=5) for Pb and Al, which was validated through the analysis of certified reference tea and poplar leaves samples. The biosorption capacity of immobilized Agaricus arvensis for Pb and Al was found to be 31.2 mg g-1 and 45.7 mg g-1, respectively. The developed method was applied to determine the concentrations of Pb and Al in various edible vegetable samples (cucumber, okra, tomato, beans, aubergine, watermelon, zucchini, pepper, melon, lettuce, roka, purslane, scallion, cress, parsley, cabbage, sugar cane, and basil) grown along the cultivated banks of the Tigris River in Diyarbakır, Turkey.Öğe Synthesis and characterization of 1,2-bis(2-(5-bromo-2-hydroxybenzilidenamino)-4-chlorophenoxy)ethane ant its metal complexes:An experimental, theoretical, electrochemical, antioxidant and antibacterial study(Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014) İlhan, Salih; Baykara, Haci; Tomsuk, Abdussamet; Okumuş, Veysi; Levent, Abdulkadir; Seyitoğlu, Salih; Özdemir, SadinA new Schiff base ligand was synthesized by reaction of 5-bromosalicylaldehyde with 1,2-bis(4-chloro-2- aminophenoxy)ethane. Then the Schiff base complexes were synthesized by the reaction of metal salts and the novel Schiff base. The molar conductivity properties of the complexes were studied and found out that the complexes are nonelectrolytes. The structures of the ligand and its metal complexes were characterized by elemental analysis, FT-IR, UV–VIS, magnetic susceptibility measurements, molar conductivity measurements, and thermal gravimetric analysis. In addition antioxidant, theoretical NMR studies and cyclic voltammetry of the complexes were done. Two methods namely metal chelating activity and diphenylpicrylhydrazyl (DPPH) radical scavenging method were used to determine the antioxidant activity, and antibacterial properties of the compounds were also studied.Öğe Synthesis, Aggregation, Antioxidant and DNA-Binding Properties of Metallophthalocyanines Bearing 5-Tert-butyl-2-hydroxyphenoxy groups(Chemistry Select, 2017) Ağırtaş, Salih; Cabir, Beyza; Özdemir, Sadin; Okumuş, Veysi; Aslantaş, AliIn this study, the synthesis and characterization of new substituted metallophthalocyanines are described. A new phthalonitrile, 4-(5-tert-butyl-2-hydroxyphenoxy)-5-chlorophthalonitrile (3) was prepared. New compounds were characterized by UV–Vis, IR, 1HNMR, and elemental analysis. The aggregation behavior of the cobalt (II), magnesium (II) and copper (II) phthalocyanines were studied in tetrahydrofuran and in known concentration ranges. The antioxidant activities of compounds were evaluated. Their radical-scavenging capacity, metal chelating activity and reducing power was fully studied. The compound 3 showed 100% chelating activity as EDTA at concentration 50 mg/L. The DNA interaction of copper (II) phthalocyanine compound (6) was studied using UV/Vis titration, gel electrophoresis, cyclic voltammetry. The results indicated that compound 6 interacts with CT-DNA via intercalation binding mode.
