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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 Design of novel binuclear phthalocyanines formed by dioxyphenyl bridges: Synthesis and investigation of thermal and antioxidant properties(Zeitschrift für anorganische und allgemeine Chemie., 2012) Ağırtaş, Salih; Gümüş, İlkay; Okumuş, Veysi; Dündar, Abdurrahman4,4_-(1,4-Phenylenebis(oxy)diphthalonitrile was synthesized by reaction of hydroquinone with 4-nitrophthalonitrile. Binuclear metallophthalocyanines 2–4 were obtained by the reaction between 4,4_-(1,4-phenylenebis(oxy)diphthalonitrile and 4-(benzo [d] [1,3] dioxol- 5-ylmethoxy)phthalonitrile in the presence of metal salts. These new compounds were characterized by using elemental analysis, FTIR, 1H-NMR and UV/Vis spectroscopic data. Thermal properties of phthalocyanines 2-4 were investigated by TG and DTA. In addition, antioxidant properties of compounds II, 3 and 4 were investigated. Their radical-scavenging capacity and chelating effects was fully studied. The maximum 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH) were obtained from compound 3. Chelating effects on ferrous ions were 91.6 % at concentration of 100 mgL–1 with compound II.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-Isopropyl-6-methylpyrimidin-4-yloxy substituents: synthesis, characterization, aggregation behavior, antioxidant and antibacterial activity, and electronic properties.(Zeitschrift für und allgemeine Chemie., 2014) Ağırtaş, Salih; Dede, Emrah; Gümüş, Selçuk; Dündar, Abdurrahman; Okumuş, VeysiA novel phthalonitrile derivative bearing 2-isopropyl-6- methylpyrimidin-4-yloxy substituents at peripheral positions was synthesized by a nucleophilic substitution reaction. Metallophthalocyanines were obtained from the reaction of the novel phthalonitrile with metal Zn, Cu, Co, and Ni salts. The characterization of the compounds was performed using elemental analysis as well as UV/Vis, FT-IR, and 1H-NMR spectroscopy. The aggregation behaviors of phthalocyanine complexes were also investigated. These metallophthalocyanines do not show any aggregation behavior between 10–4–10–6 M concentration range in THF. The antioxidant activities of the synthesized com-pounds were evaluated using three different tests: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, metal chelating activity, and reducing power assays. All the compounds exhibited various antioxidant activities. In addition, antimicrobial activity of the compounds was tested over four gram positive and two gram negative bacteria. 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 arrangements and electronic structure.Öğe Novel cobalt (II), zinc (II) phthalocyanines bearing discrete substituents: Synthesis, characterization, aggregation behavior, electrochemical properties and antioxidant activity(Synthesis and Reactivity in Inorganic, Metal-Organic & Nano Metal Chemistry, 2014) Ağırtaş, Salih; Cabir, Beyza; Dündar, Abdurrahman; Okumuş, Veysi; Ceyhan, GökhanA new phthalonitrile derivative bearing 3,4,5-trimethoxybenzyloxy and chloro-substituents at peripheral position was prepared by a nucleophilic displacement reaction. Cyclotetramerization of phthalonitrile derivative in dimethylsulfoxide (DMSO) gave the metallophthalocyanines. Novel Co(II), Zn(II) phthalocyanines (Pcs) were obtained from the reaction 4-[(3,4,5- trimethoxybenzyloxy]-5-chlorophthalonitrile and metal salts. The novel compounds have been characterized by using elemental analysis, UV-Vis, FTIR, 1H-NMR spectral data. The aggregation behaviors of Co(II), Zn(II) Pcs were also investigated. These metallophthalocyanines do not show any aggregation behavior between 1.2 × 10−5 and 4.0 × 10−6Mconcentration range in DMF. The antioxidant activities of Pcs were investigated antioxidant assays such as free radical scavenging ability of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferrous ion chelating ability. Furthermore, the redox properties of the Pcs complexes were investigated by using cyclic voltammetry.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 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 a new di-functional ligand and its metal complexes: an experimental, theoretical, cyclic voltammetric and antimicrobial study.(Synthesis and Reactivity in Inorganic, Metal-Organic & Nano Metal Chemistry, 2015) Baykara, Haci; İlhan, Salih; Tomsuk, Abdussamet; Seyitoğlu, Salih; Levent, Abdulkadir; Okumuş, Veysi; Dündar, AbdurrahmanA new difunctional Schiff base ligand and its some metal complexes were synthesized. The compounds were characterized by elemental analysis, 1H-NMR, 13C-NMR, FT-IR, UV-VIS, magnetic susceptibility measurements, molar conductivity measurements, and thermal gravimetric analysis techniques. Additionally, DPPH scavenging, metal chelating and antibacterial activity of compounds were examined via in vitro methods. The lowest DPPH scavenging activity observed by Co(II) as 36.28% and highest was ligand as 52.00%. A cyclic voltammetric study was also carried out to determine redox potentials of the compounds. Some theoretical studies such as 1H-NMR, HOMO-LUMO, and mapped electron density of the ligand were also carried out successfully.Öğe Synthesis, characterization, aggregation behavior, antioxidant activity, and antibacterial activity of metallophthalocyanines carrying four phthalonitriles group(Editions de l'Academie Republique Populaire, 2016) Güven, M. Emin; A?irtaş, M. Salih; Özdemir, Sadin; Dündar, Abdurrahman(Formula presented) A novel phthalonitrile derivative and zinc (II), cobalt (II), and cupper (II) phthalocyanines complexes were synthesis and characterized. The novel compounds have been characterized by using various spectroscopic data FTIR, UV/vis, NMR, elemental analysis etc. The aggregation investigations carried out in different concentrations indicate that 4- (4-(1-(4- phenoxyphenyl)-1-phenylethyl)phenoxy)phthalonitrile substituted phthalocyanine compounds do not have any aggregation behavior for the concentration range of 10-4-10-5 M in tetrahydrofuran. The antioxidant properties of the phthalonitrile and its phthalocyanine compounds were evaluated in three series of in vitro tests: DPPH free radical scavenging, ferrous ion chelating activity and reducing power. Antimicrobial activities of compounds were investigated.Öğe The use of fungal biomass agaricus bisporus immobilized on amberlite XAD-4 resin for the solid phase preconcentration of thorium(Bioremediation Journal, 2014) Özdemir, Sadin; Okumuş, Veysi; Dündar, Abdurrahman; Kılınç, ErsinSolid-phase extraction method was developed for the preconcentration of thorium (Th). Fungal biomass Agaricus bisporus was immobilized to Amberlite XAD-4 as solid-phase sorbent. The critical parameters such as pH of the sample solution, flow rate of the sample, volume of the sample, and the effect of major ions that affect the preconcentration of thorium in this system were evaluated. The optimum pH for the sorption of Th is 6.0, and quantitative elution occurs with 1.0 mol L−1 HCl. The loading capacity was determined as 0.079 mmol g−1. The optimized method was validated through analysis of the certified reference material of tea leaves (NCS ZC73014) and successfully applied to the determination of Th in a real ore sample with satisfactory results.
