Organik ve Konvansiyonel Tarım Ürünlerinde Eser Düzeydeki Bakır, Kadmiyum ve Kurşun İyonlarının Değiştirilebilir Çözücü Bazlı Sıvı Faz Mikroekstraksiyonu ve Alevli Atomik Absorpsiyon Spektrometrisi İle Tayini

Abstract

In this thesis, in order to determine the amount of copper, cadmium and lead in organic and conventional growth food samples switchable solvent based dispersive liquid-liquid microextraction (SHS-DLLME) method is developed. The method uses flame atomic absorption spectrometry (FAAS) with micro-sampling system to determination of the amount of heavy metal ions. In the technique, decanoic acid used as extraction solvent, also called smart solvent, is an environmentally friendly fatty acid whose polarity can be adjusted by changing pH. In order to obtain hydrophobic complexes of heavy metals, 8-Hydroxyquinoline (8-HQ) is used as a complexing agent. Formation of CO2 is provided by using Na2CO3 as an effervescence agent and H2SO4 as a proton donor. At the end of the extraction, decanoic acid extraction phase, which is solid at room conditions, is easily removed from the aqueous phase with the help of a spatula and diluted with acidic ethanol then analyzed by FAAS with micro-sampling system. In the developed method, the effects of pH, volume of decanoic acid, volume and concentration ratio of Na2CO3 and H2SO4, volume of complexing agent, extraction temperature and potentially interfering ions on the extraction efficiency and the enhancement factor are investigated. Under the optimal conditions, for Cu(II), Cd(II) and Pb(II), the enhancement factor (EF) 52, 47, 45; limit of detection (LOD) 0.75 µg L-1, 0.69 µg L-1, 2.88 µg L-1 and limit of quantification (LOQ) 2.52 µg L-1, 2.30 µg L-1, 9.59 µg L-1 are obtained respectively. The proposed method has been applied to both certified reference material and organic and conventional growth food samples. Obtained results proved that the proposed SHS-DLLME method is a sensitive, repeatable, fast and easy-to-apply to enhancement and determination of Cu(II), Cd(II) and Pb(II) contents of organic and conventional growth food samples. In addition, it is also assumed to be suitable process for the economic and environmentally friendly green analytical chemistry approach with the using of new generation smart solvents. There are two important features that make proposed study different from similar studies. The first is that the dispersion is completed in a short time without the need for any external energy owing to the effervescence formed during the extraction procedure. The other is that decanoic acid, one of the new generation smart solvents, solidifies easily at room conditions, making phase separation very easy and with high efficiency. This allows the extraction to be completed in a very short time.