Some processes occuring in graphite furnaces used for electrothermal atomic absorption spectrometry in the presence of organic chemical modifiers

✍ Scribed by Anatoly B. Volynsky; Segei V. Tikhomirov; Valery G. Senin; Alexander N. Kashin

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 960 KB
• Volume: 284
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(93)85322-b

✦ Synopsis

Abatraet

Under stabilized-temperature platform furnace (STPF) conditions ascorbic acid does not significantly affect the peak areas for lead and tin and increases the peak area 1.37-fold for gallium. The appearance times for all three elements increase in the presence of ascorbic acid. The thermal decomposition of a number of organic chemical modifiers in an argon atmosphere was studied by means of thermal and elemental analysis. It was shown that the ascorbic acid melt wets lead and gallium oxides better than the ghtcose melt. By the use of an electron microprobe it was shown that after drying and ashing at SXPC of a solution containing ascorbic acid, lead and gallium, only 7% and 14% of the corresponding metal was retained on the surface of the carbon residue. For glucose the values were 25% and 30%, respectively. It is proposed that the increase in appearance time for the analytes studied in the presence of ascorbic acid is a result of their diffusion from the carbon residue at the atomization stage. The sensitivity enhancement in the presence of ascorbic acid, which was obsetved earlier for lead, tin and a number of other elements, was caused by the substantial changes in the composition of the gas phase in the electrothermal analyser under non-STPF conditions.