Su Örneklerinde Kurşun Ve Kobalt İyonlarının Alevli Atomik Absorpsiyon Spektrofotometresi İle Tayini İçin Yeni Bir Metot: Ultrason Emülsifikasyonu Destekli- İkili Katılaştırılmış Yüzen Organik Damla Mikroekstraksiyonu

Abstract

In this thesis, a simple, economical and environmentally friendly ultrasonic emulsification assisted dual solidified floating organic drop microextraction technique (USAE-dSFODME) was developed for the preconcentration of lead and cobalt prior to its flame atomic absorption spectrophotometric determination. In this technique two SFODME steps are applied in sequence. The classical SFODME applied as the first step and then the second (back-extraction) step was applied. For the classical SFODME metal ions were complexed with Congo Red and then extracted into 1-dodecanol. After this stage, a second extraction step was performed instead of direct determination of the analyte ion in the classical method. For this purpose, the organic phase containing the extracted analyte ions is treated with 1.0 mol L-1 HNO3 solution and then exposed to ultrasonication. So, the analyte ions were back-extracted into the aqueous phase. Finally, the analyte ions in aqueous phase were determined by FAAS directly. During the thesis several factors affecting the microextraction as efficiency such as pH, complexing agent type and its concentration, extraction time, sample volume and extraction temperature were investigated and optimized. Under the optimum conditions, the enrichment factor, limit of detection (LOD) (3S/m), limit of quantification (LOQ) (10S/m) and relative standard deviation (RSD) were calculated. The proposed method was successfully applied to the determination of lead and cobalt in certified reference material and different water samples. There are two important features of thesis: The first is implementation of ultrasound energy shortens the extraction time and improves the extraction efficiency. Second, by performing a second extraction step, drawbacks of 1-dodecanol in conventional SFODME (clogging of pipes and tubings of instrument) are eliminated. The results showed that USAE-dSFODME combined with FAAS is a fast, simple, sensitive, cheap, having minimum organic solvent consumption and efficient analytical method for the preconcentration and determination of trace amounts of Pb(II) and Co(ll) ions.