Elsherif, Khaled:

Simultaneous determionation of trace elements using-element graphite furnace atomic absorption spectrometry

Duisburg, Essen (2009), 192 S.
Dissertation / Fach: Chemie
Fakultät für Chemie » Analytische Chemie
Kuß, Heinz-Martin (Doktorvater, Betreuerin)
Telgheder, Ursula (GutachterIn)
Duisburg-Essen, Univ., Diss., 2009
Abstract:
Simultaneous Multi-Element Atomic Absorption Spectrometer (SIMAA 6000) has been used to determine groups of elements (up to four) simultaneously, by using 2-operating and 4-operating modes. A direct, simple, fast and accurate methodology for the simultaneous multi-element determination have developed. Compromised conditions (e.g. temperature program and use of universal modifier) for the multi-element mode have been determined. The temperature program has been carefully optimized for the multi-element mode taking into account all analytes to be determined. The optimization depends on the elements to be determined simultaneously and the matrix. Also, a universal powerful matrix modifier has been used in order to increase the stability of the elements (especially the volatile elements). This has permitted the use of a common temperature program including volatile and less volatile elements. The Pd+Mg mixture modifier has stabilized the high and mid volatile elements. For less volatile elements, the modifier had no stabilization effect on these elements. But the modifier in this case has prevented the formation of refractory compounds which increase the volatilization process of these elements. Ir coating of the tube or platform has extended significantly the tube lifetime. The sensitivity values for the multi-element determination were comparable to those of the single-element. The decreasing in sensitivity values is a result of using higher atomization temperature in the multi-element mode and/or decreasing the lamp intensities. The detection limits values of the multi-element determination were higher than those of the single-element which is mainly as a result of decreasing the lamp intensities in the multi-element mode compared to the single-element mode. Another effect which could cause the higher detection limits is the use of higher atomization temperature. The operational conditions (the temperatures, use of modifier, and the operating mode) have affected the absorption signals of the elements. This effect has appeared in terms of increasing or decreasing the appearance time, peak height, and peak width. The accuracy of the methods was tested by analyzing number of certified materials and the concentrations obtained were in good agreement with certified values