Determination of silver by slotted quartz tube atom trap flame atomic absorption spectrometry using metalcoatings

Karaman, Gamze
Silver is a precious metal having antibacterial property and widely used in industry mostly for water purification and medicinal products. Therefore, the determination of trace levels of silver is important for industrial applications. Flame atomic absorption spectrometry (FAAS) is a popular technique for the determination of relatively low concentration levels. This mature technique owes its widespread application to its simplicity and low cost. However, for some occasions, FAAS technique suffers from its low sensitivity because of low nebulization efficiency and relatively short residence time of analyte atoms in the measurement zone. In order to overcome this sensitivity problem, atom traps have been developed in recent years. Slotted quartz tube (SQT) is an accessory designed to use as an atom trap in conventional flame atomic absorption burner head. This thesis study involves the development of a sensitive, simple and economical technique with the help of the SQT for the determination silver. Firstly, the technique known as SQT-FAAS was used to increase the residence time of analyte atoms in the measurement zone. In this case, limit of detection (LOD) and characteristic concentration (C0) values were found to be 19 ng/mL and 35 ng/mL, respectively. Enhancement in sensitivity with respect to FAAS was found to be 2.31 fold using SQT-FAAS. Regarding the angle between the two slots of the SQT, 180° configuration was used. Secondly, in order to improve sensitivity further, the SQT was used as an atom trap (AT) where the analyte is accumulated in its inner wall prior to re-atomization. The signal is formed after reatomization of analyte atoms on the trap surface by introduction of organic solvent. For this purpose, uncoated SQT was used as a trap medium. However, there was a memory effect. Therefore, the SQT inner surface was coated with different coating elements and theoptimum conditions were found by using W-coated SQT-AT-FAAS technique. In the presence of a lean air-acetylene flame, analyte atoms were trapped in the inner surface of the SQT for 5.0 min and then revolatilized with the introduction of 25 μL isobutyl methyl ketone (IBMK); afterwards, a transient signal was obtained. These optimized parameters were used for uncoated SQT, W-coated SQT and Zr-coated SQT atom trap techniques. Sample suction rate was 6.25 mL/min in all techniques. Sensitivity was increased 54 fold using uncoated SQT-AT-FAAS technique with respect to simple FAAS technique. When W-coated SQT-AT-FAAS technique was applied, 135 fold sensitivity enhancement was obtained with respect to FAAS technique. The best sensitivity enhancement, 270 fold, was obtained using Zr-coated SQT-AT-FAAS technique. In addition, the Ag signals were more reproducible (%RSD, 1.21) when Zr was used as a coating element. After the sensitive technique was developed, interference effects of some transition and noble metals and hydride forming elements on Ag signals were investigated. Finally, surface studies were done to determine the chemical state of Ag during trapping period by using X-ray Photoelectron Spectroscopy (XPS). It was observed that the Ag analyte is retained on the SQT surface in its oxide form.


Determination of cadmium using slotted quartz tube atom trap atomic absorption spectrometry and metal coatings
Özcan Gurbetçioğlu, G. Pelin; Ataman, Osman Yavuz; Department of Chemistry (2010)
Flame atomic absorption spectroscopy (FAAS) is a common technique for detecting metals and metalloids in environmental, biological and metallurgical samples. Although it is a rather old technique, it is still very reliable, simple to use and inexpensive. The technique can be used to determine the concentration of over 70 different metals in a solution. However, it has detection limits at mg/L levels. Some atom trapping methods have been developed to reach the detection limits of ng/mL levels. Slotted quartz...
Addition of carbonyl compounds to the cyclic olefins : synthesis of cyclitols
Altun, Yasemin; Balcı, Metin; Department of Chemistry (2008)
Cyclitols have attracted a great deal of attention in recent years owing to biological activities exhibited by them and also their usefulness in the synthesis of other natural products and pharmaceuticals. Carbasugars are also a derivative of cyclitols and they are cyclic monosaccharide analogues which posses CH2OH group in their structure. In this study, novel synthetic strategies leading to cyclitol derivatives were investigated and the synthesis of tetraol (72) and pentaol (73) derivatives containing CH2...
Determination of thallium by volatile compound generation atomic absorption spectrometry
Ataman, Seval; Ataman, Osman Yavuz; Department of Chemistry (2011)
Determination of thallium is important due to its toxic effects on the environment and human health. Extremely low abundance of thallium in earth crust requires very sensitive and accurate methods for determination of this element. Although volatile compound generation is a sensitive, fast and economical method, thallium determination by this method has not been sufficiently investigated in literature, because of the fact that the formation of volatile forms of this element is a difficult task. A continuous...
Determination of silver by chemical vapour generation and atomic absoption spectrometry
Öztürk, Çağla Pınar; Ataman, Osman Yavuz; Department of Chemistry (2004)
A method for determination of silver has been developed based on chemical vapour generation atomic absorption spectrometry (CVGAAS). Volatile species of silver in acidified medium were generated by the reduction of sodium tetrahydroborate; these species were sent to a flame-heated quartz tube atomizer (QTA) following isolation by using a gas-liquid separator. Flow injection (FI) was used for sample introduction. Optimization of parameters such as; concentrations of acid and NaBH4 concentration, flow rates o...
Preparation and characterization of carbon supported platinum nanocatalysts with different surfactants for C1 to C3 alcohol oxidations
Ertan, Salih; Gökağaç Arslan, Gülsün; Department of Chemistry (2011)
In this thesis, carbon supported platinum nanoparticles have been prepared by using PtCl4 as a starting material and 1-octanethiol, 1-decanethiol, 1-dodecanethiol and 1-hexadecanethiol as surfactants for methanol, ethanol and 2-propanol oxidation reactions. The structure, particle sizes and surface morphologies of the platinum were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). XRD and TEM results indicate that all prepared catalysts have ...
Citation Formats
G. Karaman, “Determination of silver by slotted quartz tube atom trap flame atomic absorption spectrometry using metalcoatings,” M.S. - Master of Science, Middle East Technical University, 2011.