Preconcentration and speciation of iron by using renewable surface flow injection system (RS-FIA)


Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Arts and Sciences, Department of Chemistry, Turkey

Approval Date: 2003

Thesis Language: English

Student: Serap Tekin

Supervisor: MÜRVET VOLKAN

Abstract:

The main aim of this study is to combine the sol-gel technology and renewable surface flow injection analysis (RS-FIA) techniques for iron speciation and determination. Thus the home-made FIA system, which consists of 2 syringe pumps and 3 multi-position selection valves, is modified with two flow cells (magnetic cell and jet ring cell) in order to be suitable for renewable surface flow injection technique. All the computer programs used for flow injection analysis are modified to control the whole system automatically. Two different types of solid phase extraction materials are used for the speciation of iron in aqueous systems. Magnetic beads coated with primary amino groups are utilized for the determination of Fe (III). The magnetic bead reactor is created within the flowing stream by retaining the magnetic beads with a home-made electromagnet. The elution cycle for Fe (III) is done with 0.1 M EDTA solution and determined on-line by transferring to an atomic absorption spectrometer. The spent beads are collected off-line and regenerated. For the preconcentration of Fe (II), ferrozine doped sol-gel beads are prepared as reactive and disposable surfaces. These beads are handled by the system equipped with a jet ring cell which is connected on-line to a portable UV-VIS fiber optic spectrometer. Amino sol-gel and ferrozine-doped sol-gel beads are prepared using sol-gel technology and characterized by using surface techniques. Their performances in preconcentration and speciation of iron and the influence of different experimental parameters such as pH, the sequence of reagents, reactor lengths and reaction periods on the flow system are investigated. Renewable surface flow injection analysis is performed by either bead injection or sequential bead injection methods.