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    gamma-Fe2O3 magnetic nanoparticle functionalized with carboxylated multi walled carbon nanotube for magnetic solid phase extractions and determinations of Sudan dyes and Para Red in food samples
    (ELSEVIER SCI LTD, 2018) Kilinc, Ersin; Celik, Kadir Serdar; Bilgetekin, Havin
    Hybrid nanostructures composed of gamma-Fe2O3 (maghemite) and carboxylated-multi walled carbon nanotube (cMWCNT) were used for the magnetic solid phase extractions and determination of Sudan I, II, III, IV, Para Red, Sudan Black B and Sudan Red 7B in chili products. High performance liquid chromatography (HPLC) was employed for the measurements. Limit of quantification (LOQ) values were found in the range 0.44-2.82 ng mL(-1) for analytes. The best extraction parameters were determined as pH 8.0, 40 mg of magnetic nanoparticle, 4.0 min of contact time, 0.3 mL desorption by acetonitrile. The samples were dissolved in acetone-dichloromethane-methanol (3: 2: 1, v/v/v) and diluted with acetonitrile-methanol (v/v; 80: 20) before the method was applied. Concentrations of Sudan dyes and Para Red were determined in four samples of chili powder from less than LOQ to 31.21 +/- 1.6 ng g(-1), two samples of chili tomato sauces (lower than LOQ) and two samples of ketchup (lower than LOQ).
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    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, Ersin
    Coriolus 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).
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    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.