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    A sensitive and accurate analytical method for the determination of cadmium in food samples: Molybdenum coated T-shape slotted quartz tube flame atomic absorption spectrophotometry
    (Elsevier Sci Ltd, 2020) Kasa, Nursu Aylin; Buyukpinar, Cagdas; Erulas, Ahmet Fatih; Bakirdere, Sezgin
    In this study, a molybdenum coated T-shaped slotted quartz tube atom trap flame atomic absorption spectrophotometry method (Mo coated-T-SQT-AT-FAAS) was developed for the determination of cadmium with on-line preconcentration. Inner surface of T-SQT was coated with molybdenum to enhance the trapping efficiency. Hydrogen gas was used instead of organic solvents to release trapped atoms. Limit of detection and quantification were found to be 0.057 and 0.082 mu g/L, respectively. The developed method has a linear working range between 0.10 and 1.0 mu g/L with a low %RSD value (< 3.7). About 1202 times enhancement in detection power was recorded over the conventional FAAS system. Recovery experiments were used to determine the applicability of the method developed to real samples (linden, milk powder and mint) and significant results (94.4-100.7%) were obtained for the samples spiked at 0.30, 0.50 and 1.0 mu g/L. The method was also applied to Tomato Leaves 1573a SRM to check the accuracy.
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    Accurate and sensitive determination of lead in black tea samples using cobalt magnetic particles based dispersive solid-phase microextraction prior to slotted quartz tube-flame atomic absorption spectrometry
    (Elsevier Sci Ltd, 2019) Akkaya, Erhan; Erulas, Fatih Ahmet; Buyukpinar, Cagdas; Bakirdere, Sezgin
    Newly developed combination of magnetic cobalt particles based dispersive solid-phase microextraction (Co-MP-DSPME) and slotted quartz tube attached flame atomic absorption spectrometry (SQT-FAAS) was utilized to determine lead at trace levels in tea samples. Co-MPs' adsorbent properties were tested and validated for their selectiveness to lead. Only with a few and short extraction steps (i.e. adding MPs, mixing, decanting and eluting) analyte was extracted from sample solution rapidly and efficiently. Limit of detection (LOD) and limit of quantification (LOQ) for the developed method (Co-MP-DSPME-SQT-FAAS) were found to be 7.77 mu g/L and 25.9 mu g/L, respectively. Matrix matching strategy was performed and outcomes indicated that the developed method is applicable with the high percent recovery values of 110.1 +/- 4.5 and % 102.9 +/- 4.2 for 100 and 300 mu g/kg lead standard spiked black tea samples, respectively. The method was also applied to standard reference material to check the accuracy of the method.
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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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    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.