In Fig. 2B the comparison of pyrolysis and atomization curves for
1 ng of Sb in aqueous solution and for slurry prepared from NIST 2709
using 30 μg of Ir+ 2 μg of W as permanent modifiers in the presence of
PTFE suspension is shown. In the case of pyrolysis curve the similar
behavior as for Ir/Nb modification is observed. In turn, atomization
curves for Sb in aqueous solution and slurry prepared from NIST 2709
are different especially for temperature higher than 2000 °C.
Comparing integrated absorbance values for both modifications it is
obvious that the sensitivity of Sb determination in the case of Ir/Nb
modification is about 30% higher than for Ir/W modification.
Moreover, it is worthwhile to note that the chemical and thermal
resistance of NbC formed on the graphite surface is better than that of WC [21]. For this reasons for further experiments graphite furnace
modified by Ir/Nb was chosen