Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Erdem, Aslı

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  • Article
    Citation - WoS: 28
    Citation - Scopus: 28
    Speciation and Preconcentration of Inorganic Antimony in Waters by Duolite Gt-73 Microcolumn and Determination by Segmented Flow Injection-Hydride Generation Atomic Absorption Spectrometry (sfi-Hgaas)
    (Elsevier Ltd., 2005) Erdem, Aslı; Eroğlu, Ahmet Emin
    A selective matrix removal/separation/enrichment method, utilizing a microcolumn of a chelating resin with SH functional groups (Duolite GT-73), was proposed for the determination of Sb(III) in waters by segmented flow injection-hydride generation atomic absorption spectrometry (SFI-HGAAS). The resin was selective to Sb(III) at almost all pH and acidity values employed, whereas Sb(V) was not retained at all and could be determined after a pre-reduction step with l-cysteine. Spike recoveries were tested at various concentration levels in different water types and were found to vary between 85 and 118%. Accuracy of the proposed methodology was checked by analyzing a standard reference material and a good correlation was found between the determined (13.3 ± 1.1 μg l-1) and the certified value (13.79 ± 0.42 μg l-1). The method was applied to several bottled drinking water samples for antimony determination with and without preconcentration and none of the samples were found to contain antimony above the permissible level (5 μg l-1). The characteristic concentration (the concentration of the analyte corresponding to an absorbance of 0.0044) was 0.55 μg l-1 and the 3 s limit of detection (LOD) based on five times preconcentration was 0.06 μg l-1. The applicability of the microcolumn separation/preconcentration/matrix removal method for flow injection systems was also demonstrated.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 17
    Separation of Trace Antimony and Arsenic Prior To Hydride Generation Atomic Absorption Spectrometric Determination
    (Elsevier Ltd., 2005) Ural, Müşerref Yersel; Erdem, Aslı; Eroğlu, Ahmet Emin; Shahwan, Talal
    A separation method utilizing a synthetic zeolite (mordenite) was developed in order to eliminate the gas phase interference of Sb(III) on As(III) during quartz furnace hydride generation atomic absorption spectrometric (HGAAS) determination. The efficiency of the proposed separation method in the reduction of suppression effects of transition metal ions on As(III) signal was also investigated. Among the volatile hydride-forming elements and their different oxidation states tested (Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), and Te(VI)), only Sb(III) was found to have a signal depression effect even at low (μg l−1) concentrations under the experimental conditions employed. It has been shown that mordenite adsorbs Sb(III) quantitatively, even at a concentration of 1000 μg l−1, at pHs greater than two, and also, it reduces the initial concentrations of the transition metal ions to lower levels which can be tolerated in many studies. The adsorption of Sb(III) on mordenite follows the Freundlich isotherm and is endothermic in nature.
  • Article
    Citation - WoS: 50
    Synthesis of Aminopropyl Triethoxysilane-Functionalized Silica and Its Application in Speciation Studies of Vanadium(iv) and Vanadium(v)
    (Elsevier Ltd., 2011) Erdem, Aslı; Shahwan, Talal; Çağır, Ali; Eroğlu, Ahmet Emin
    A solid phase extraction sorbent, aminopropyl triethoxysilane-functionalized silica was prepared and used for vanadium speciation prior to inductively coupled plasma mass spectrometric determination. The necessary sorption parameters such as sorption pH, reaction temperature, sorbent amount and sample volume were optimized. The sorption for V(V) and V(IV) under the optimized conditions was 98% (±1) and was lower than 10%, respectively. The sorption process was investigated both from a kinetic perspective and also in terms of Freundlich, Dubinin-Radushkevich and Langmuir isotherm models to characterize the uptake of vanadate ion by the functionalized silica. Desorption from the sorbent was realized with 0.5 mol L−1 thiourea prepared in 0.2 mol L−1 HCl. Among the possible interfering species tested, Te(IV), Se(IV), Se(VI) and Fe(III) showed interference effects with V(V) signal. The validity of the method was first checked via spike recovery experiments with four different types of water; namely ultra pure, bottled drinking, tap, and sea water for different concentrations of V(V). The percent recovery values changed between 87 and 108 for all water types. The accuracy of the proposed methodology was also checked by analyzing a standard reference material (NIST, SRM 1643e) and a good agreement was found between the determined and the certified value. The proposed methodology has also been shown to be applicable for the separate sorption of V(V) in the absence/presence of V(IV) and for the sorption of both V(IV) and V(V) in waters. The amount of V(IV) can then be determined from the difference.