Tellurium speciation using hydride generation atomic absorption spectrometry and in-situ graphite cuvette trapping

Yıldırım, Emrah
In recent years speciation analysis is becoming more important as it is known that each chemical form of an element behaves differently in biological and environmental media. Since abundance of tellurium in earth crust is extremely low, very sensitive and accurate methods are needed to determine the concentration of tellurium. Hydride generation atomic absorption is a sensitive, fast and economical technique applied for the determination of tellurium. Speciation of tellurium can be achieved by making use of different kinetic behaviors of Te(IV) and Te(VI) upon its reaction with sodiumborohydride. A continuous flow hydride generation system was developed and parameters that affect the analytical signal were optimized. Sample solutions were prepared in 4.0 mol/L HCl; as reductant 0.5 % (w/v) sodiumborohydride in 0.5 % (w/v) NaOH was used. Quantitative reduction of Te(VI) was achieved through application of a microwave assisted prereduction of Te(VI) in 6.0 mol/L HCl solution. Sensitivity of the system was further enhanced by in-situ trapping of the formed H2Te species in a previously heated graphite furnace whose surface was modified using Pd or Ru. Overall efficiency of pyrolytic coated graphite surface was found to be 15% when hydrides are trapped for 60 seconds at 300 oC. LOD and LOQ values were calculated as 86 pg/mL and 287 pg/mL according to peak height values. Efficiency was increased by 46% and 36% when Pd and Ru modifiers were used, respectively. With Ru modified graphite tube 173 fold enhancement was obtained over 180 seconds trapping period with respect to direct ETAAS. LOD values were 6.4 and 2.2 pg/mL for Pd and Ru treated systems, respectively, for 180 s collection of 9.6 mL sample solution.


Inorganic antimony speciation using tungsten coil atom trap and hydride generation atomic absorption spectrometry
Akay, Pınar; Ataman, Osman Yavuz; Department of Chemistry (2010)
Antimony is a toxic element which is mostly found in two oxidation states (III and V) in environmental, biological and geological samples. Antimony may form various inorganic and organic compounds that exhibit differences in analytical behavior, toxicity and mobility; inorganic compounds of antimony are more toxic than organic forms and toxicity of Sb(III) has been shown to be 10 times higher than that of Sb(V). Therefore selective determination of Sb(III) and Sb(V) is required in environmental and biologic...
Organoclay preparation for anionic contaminant removal from water
İnam, Deniz; Göktürk, Emine Hale; Department of Chemistry (2005)
Increasing concern about the pollution of environment by inorganic and organic chemicals arising from naturally occurring ecological events and industrial processes has created a need for the search of new techniques in the removal of these contaminants. One of the natural material that can be used in such processes is clay. Clay minerals have large surface areas and high cation exchange capacities which enables them to be modified by cationic surfactants. The material prepared, often called as ءorganoclay̕...
Electrochhemical hydride generation and tungsten trap atomic absorption spectrometry for determination of antimony
Yıldıran, Ahmet; Ataman, Osman Yavuz; Department of Chemistry (2008)
Electrochemical hydride generation is an alternative technique to the chemical hydride generation by NaBH4 which is widely used for atomic spectrometric determination of volatile elements such as As, Bi, Ge, Pb, Sb, Se, Sn and Te. The aim of this research has been to develop an analytical technique at the level of ng/L for determination of antimony by using a simple and inexpensive AA spectrometer and the other parts that can be built in any laboratory. Carbon rod and platinum foil were used as cathode and ...
On-line preconcentration of vapor forming elements on resistively heated w-coil prior to their determination by atomiz absorption spectrometry
Cankur, Oktay; Ataman, Osman Yavuz; Department of Chemistry (2004)
Vapor generation in atomic spectrometry is a well established technique for the determination of elements that can be volatilized by chemical reactions. In-situ trapping in graphite furnaces is nowadays one of the most popular methods to increase the sensitivity. In this study, resistively heated W-coil was used as an online trap for preconcentration and revolatilization of volatile species of Bi, Cd and Pb. The collected analyte species were revolatilized rapidly and sent to a quartz Ttube atomizer for AAS...
Preparation and characterization of surface enhanced raman scattering substrate through electro deposition of silver-pedot film on ito glass surface
Doğan, Üzeyir; Volkan, Mürvet; Department of Chemistry (2011)
Detection of chemicals is a vital part of chemistry. For this reason, many detection systems are developed by scientists and every detection system has its own advantages. Raman spectroscopy is one of these detection systems having many advantages. However, this technique suffers from low signal intensity disadvantage. By developing a well prepared substrate, this problem can be easily solved; moreover, even single molecule detection can be possible. In this study, a novel surface enhanced Raman scattering ...
Citation Formats
E. Yıldırım, “Tellurium speciation using hydride generation atomic absorption spectrometry and in-situ graphite cuvette trapping,” M.S. - Master of Science, Middle East Technical University, 2009.