Metal determination using the slotted quartz tube and the metal coating with atomic absorption spectrometry

The use of slotted quartz tube (SQT) in flame atomic absorption spectrometry (FAAS) provides increased the residence times of the analyte atoms in the light path. This tecnique is simple and easily applicable in any laboratory. This thesis investigates the application of SQT as well as FAAS determination of selenium and antimony. The first stages involve experiments with and without SQT in conventional flame atomic absorption spectrometry. By SQT-FAAS method, 3.65 and 2.2 times enhancement in sensitivity has been obtained with respect to conventional FAAS, and the characteristic concentration of the method was calculated as 2.9x102 ng/mL and 3.9x102 ng/mL for selenium and antimony, respectively. The second stage of investigation is about the use of SQT as an atom trap, AT, a preconcentration device for selenium and antimony determination. The similar technique has been succesfully applied to some other analytes such as Pb, Tl, Cd, Bi and Au. In the present work, the analyte atoms are trapped on the inner surface of SQT in the presence of a lean air-acetylene flame for a few minutes. After this collection step, acetonitrile and methyl isobutyl ketone (MIBK) were used for determination of selenium and antimony, respectively. The organic solvent in the range of 10-60 ?L was introduced via conventional nebulization, which caused a momentary alteration in the flame composition and thus results in the release of trapped analyte atoms from the quartz surface. This revolatilization step is followed by a rapid atomization and a transient signal was obtained. With method no sensitivity enhancement is obtained in determination of selenium. The limit of detection for antimony with SQT-AT-FAAS was 3.85 ng/mL, which was about 369 times more sensitive compared to FAAS technique. 25 mL were used with a suction rate of 6.25 mL/min. Given the succes of SQT-AT-FAAS technique for antimony determination, this technique was also utilized for determination of antimony in samples of brake. As a result of application of this technique, antimony in the samples of brake linning has been found to be at levels of ?g/g.At the final phase of the study, an novel method for coating the inner surface of SQT with metal of low volatility was applied. Various materials have been utilized for coating, but no increase in sensitivity was recorded for either selenium or antimony.