Yazar "Turak, Fatma" seçeneğine göre listele

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    A novel liquid-liquid extraction for the determination of naphthalene by GC-MS with deuterated anthracene as internal standard
    (Springer, 2017) Erarpat, Sezin; Ozzeybek, Gozde; Chormey, Dotse Selali; Erulas, Fatih; Turak, Fatma; Bakirdere, Sezgin
    Polycyclic aromatic hydrocarbons are known for their carcinogenic and mutagenic effects on human health. This therefore calls for the regulation of their concentrations in air, water, and soil. Naphthalene as the simplest in structure of the polycyclic aromatic hydrocarbons is mainly used as a starter material for other chemicals but also has impacts on human health. A method is therefore proposed for the determination of naphthalene in water samples by gas chromatography mass spectrometry after liquid-liquid extraction. The extraction method was optimized to improve the extraction output, thereby lowering the limit of detection. The limits of detection and quantification obtained for naphthalene were 4.4 and 14.6 ng mL(-1), respectively. Deuterated anthracene was used as internal standard to enhance the precision of the method, for which a relative standard deviation of 4.3% was obtained. The percent recovery of naphthalene obtained from tap water was ranged between 93.8 and 102.2.
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    Accurate and simple determination of oxcarbazepine in human plasma and urine samples using switchable-hydrophilicity solvent in GC-MS
    (Wiley, 2020) Erarpat, Sezin; Bodur, Suleyman; Ayyildiz, Merve Firat; Gunkara, Omer Tahir; Erulas, Fatih; Chormey, Dotse Selali; Turak, Fatma
    This work presents a sensitive and rapid analytical method for the determination of oxcarbazepine in human plasma and urine samples. A vortex-assisted switchable hydrophilicity solvent-based liquid phase microextraction (VA-SHS-LPME) was used to preconcentrate oxcarbazepine from the samples before the determination by gas chromatography mass spectrometry. The switchable hydrophilicity solvent was synthesized by protonatingN,N-dimethylbenzylamine with carbon dioxide to make it totally miscible with an equivalent volume of water. Parameters of the VA-SHS-LPME method including volume of switchable hydrophilicity solvent, concentration/volume of sodium hydroxide and vortex period were systematically optimized. Under the optimum conditions, good linearity ranging from 27.03 to 353.47 mu g/kg was obtained for the analyte. Limit of detection and quantitation values were found to be 6.2 and 21 mu g/kg (mass base), respectively. The relative standard deviation was calculated as 6.9% for six replicate measurements of the lowest concentration of the calibration plot. Satisfactory recovery results were calculated in the range of 97-100% for human plasma and urine samples spiked at five different concentrations.
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    Accurate determination of pesticides, hormones and endocrine disruptor compounds in complex environmental samples using matrix dilution and matrix matching with dispersive liquid-liquid microextraction
    (Walter De Gruyter Gmbh, 2018) Chormey, Dotse Selali; Firat, Merve; Buyukpinar, Cagdas; Erulas, Fatih; Komesli, Okan Tarik; Turak, Fatma; Bakirdere, Sezgin
    Quantitative determination of contaminants in environmental samples is usually hampered by low analyte recovery which results from the complex nature of the sample matrix. This study presents the application of a developed dispersive liquid-liquid microextraction method for the determination of 12 analytes in environmental samples including sea water, fresh water (lake, well and tap water), brackish water and soil samples. Matrix matched standards were used to compensate for the low analyte recovery recorded by the conventional calibration method. The effect of matrix dilution on analyte recovery was also tested. All matrix matched and matrix diluted spiked recoveries were done concurrently with calibration standards prepared in deionized water. Percent recoveries recorded for the analytes according to deionized water calibration standards ranged between 66 and 137 %. Matrix matching and matrix dilution yielded close to 100 % recovery results, but the later lowered the detection limit according to the dilution factor.
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    Arsenic speciation in water and biota samples at trace levels by ion chromatography inductively coupled plasma-mass spectrometry
    (Taylor & Francis Ltd, 2017) Firat, Merve; Bakirdere, Sezgin; Sel, Sabriye; Chormey, Dotse Selali; Elkiran, Omer; Erulas, Fatih; Turak, Fatma
    A sensitive, reliable, simple and rapid analytical method was developed for the determination of arsenite [As(III)], arsenate [As(V)] and arsenobetaine (AsB) species using ion chromatography combined with inductively coupled plasma-mass spectrometry (IC-ICP-MS). Inorganic and organic arsenic species were separated with an anion exchange column (Dionex AS9) and a 50mM sodium bicarbonate mobile phase (pH 10) at a flow rate of 1.0mL min(-1.) %RSD values were found to be lower than 5.1% for all arsenic species. The limits of detection (LOD) obtained for As(III), As(V) and AsB were 16.5 ng L-1, 14.1 ng L-1 and 6.2 ng L-1, respectively. The developed analytical method was tested using AsB certified reference material (NMIJ CRM 7901-a), and spring water certified reference material (UME CRM 1201) for accuracy check. This method was applied for the quantitative determination of arsenic species in different water samples and chicken samples as a solid matrix.
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    Simultaneous Determination of Chromium Species in Water and Plant Samples at Trace Levels by Ion Chromatography-Inductively Coupled Plasma-Mass Spectrometry
    (Taylor & Francis Inc, 2019) Sel, Sabriye; Erulas, Fatih Ahmet; Turak, Fatma; Bakirdere, Sezgin
    Ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS) was used for the identification and quantification of chromium species. Chromium(III) and chromium(VI) were separated and determined by IC-ICP-MS. The separation was achieved using an anion exchange column with 0.55 M HNO3 as mobile phase. It was a particular goal of this work to exclusively use nitric acid for elution in order to reduce interferences in the ICP-MS system. Analytical figures of merit were calculated under the optimum conditions by developing calibration plots in a concentration range of 0.50-250 mu g/L for both species. The detection limits for Cr(III) and Cr(VI) were 0.09 and 0.03 mu g/L, respectively. Spiked recovery tests were used to evaluate the applicability of the analytical method in environmental samples, and the recoveries ranged between 97 and 103% for both analytes. The accuracy of the method for total chromium content was validated through the analysis of a spring water-certified reference material (UME 1201), and the obtained results were in good agreement with the certified value. Lettuce seedlings were cultivated to evaluate the intake levels of these species. In addition, the bioaccessibility of Cr(III) and Cr(VI) from the lettuce seedlings in simulated gastric and intestinal fluids media was examined.
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    Simultaneous Determination of Harmful Aromatic Amine Products of Azo Dyes by Gas Chromatography-Mass Spectrometry
    (Pleiades Publishing Inc, 2020) Chormey, Dotse Selali; Zaman, Buse Tugba; Maltepe, Esra; Buyukpinar, Cagdas; Bulgurcuoglu, Ayse Evrim; Turak, Fatma; Erulas, Fatih Ahmet
    Azo dyes constitute about 66% of all colorants and they are widely used in industries such as textiles, plastics, ceramics, cosmetics and food. However, due to the reductive cleavage of some azo dyes into carcinogenic aromatic amines, many countries have set concentration limits or have banned the use of these azo dyes. Selected aromatic amines that pose health risk to consumers were simultaneously determined by gas chromatography mass spectrometry. A good linearity in calibration plot was obtained for the analytes and the low relative standard deviations indicated high instrumental precision. A recovery test was performed to validate the extraction method and the results obtained were between 92-114%. The method was applied to the analysis of real samples and the concentrations of aromatic amines detected were below the 30 mg/kg limit set by regulatory authorities.