Počet záznamů: 1
Investigation of in situ trapping of selenium and arsenic hydrides within a tungsten tube atomiser
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SYSNO ASEP 0162269 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Ostatní články Název Investigation of in situ trapping of selenium and arsenic hydrides within a tungsten tube atomiser Tvůrce(i) Dočekal, Bohumil (UIACH-O) RID, ORCID
Marek, Petr (UIACH-O)Zdroj.dok. Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry - ISSN 0267-9477
Roč. 16, č. 8 (2001), s. 831-837Poč.str. 7 s. Jazyk dok. eng - angličtina Země vyd. GB - Velká Británie Klíč. slova graphite furnace ; absorption spectrometry ; atomization Vědní obor RIV CB - Analytická chemie, separace CEP GA203/98/0754 GA ČR - Grantová agentura ČR CEZ AV0Z4031919 - UIACH-O Anotace The capability of in situ trapping of selenium and arsenic hydrides within a bare and modified (Pd, Pt, Ir and Re) tungsten tube atomiser (WETA) was investigated by electrothermal atomic absorption spectrometry and by a radiotracer technique using Se-75 radionuclide. Low efficiency of trapping (below 5%) was found within the bare tungsten tube. On the other hand, modification with 100 mug of Pt, Ir and Re, respectively, enhanced significantly the efficiency of trapping. Platinum-treated tubes were very efficient at collecting hydrides in the low temperature range of 100-200 degreesC, reaching efficiency close to 100%. Iridium- and rhenium-treated tubes were capable of trapping hydrides in the high temperature range of 700-900 degreesC, approaching an overall efficiency of 10%. Palladium modifier caused fatal deterioration of the tungsten tube. Low- and high-temperature mechanisms of trapping on the inner tube surface were seen, which were probably related to the low temperature dissociative chemisorption of hydrides and to the thermal decomposition of hydrides with simultaneous adsorption of products on the surface, respectively. Radiography experiments proved that the major part of selenium was collected at low temperature on a relatively small area in the central part of the platinum-treated tube opposite the injection hole. On the other hand, selenium collected at higher temperatures was found in a more diffuse area when iridium-treated and bare tubes were used. The following analytical figures of merit were found when sequestrating hydrides of selenium and arsenic within a platinum-treated tube: characteristic masses of 74 and 31 pg Se, 27 and 14 pg As pertaining to integrated absorbance and absorbance height of the signal, respectively; and limits of detection, based on 3 s-criterion, of 150 pg As and 270 pg Se were achieved. They related to a sample volume of one millilitre and fluctuation of overall blanks. The useful lifetime of platinum modified tubes reached 250 firings under optimum conditions. Pracoviště Ústav analytické chemie Kontakt Iveta Drobníková, drobnikova@iach.cz, Tel.: 532 290 234 Rok sběru 2002
Počet záznamů: 1