Elsevier, Spectrochimica Acta Part B: Atomic Spectroscopy, (103-104), p. 155-163
DOI: 10.1016/j.sab.2014.12.007
Full text: Unavailable
The on-line atomization of gold volatile species was studied and the results were compared with thermodynamic calculations in several quartz atomizers, namely: diffusion flame, flame-in-gas-shield, flame-in-plain-tube, externally heated T-tube and externally heated flame-in-T-tube. Atomization mechanism in the explored devices is proposed, where volatile species are converted to thermodynamically stable AuH at elevated temperature over 500 °C and then atomized by an interaction with a cloud of hydrogen radicals. Because of its inherent simplicity and robustness, diffusion flame was employed as a reference atomizer. It yielded atomization efficiency of 70 to 100% and a very good long time reproducibility of peak area sensitivity: 1.6 to 1.8 s µg-1 . Six and eleven times higher sensitivity, respectively, was provided by atomizers with a longer light paths in the observation volume, i.e. externally heated T-tube and externally heated flame-in-T-tube. The latter one, offering limit of detection below 0.01 µg ml-1 , appeared as the most prospective for on-line atomization. The insight into mechanism of atomization of gold volatile species, into the fate of free atoms and into subsequent analyte transfer allowed to assess possibilities of in-atomizer preconcentration of gold volatile species: it is unfeasible with quartz atomizers but a sapphire tube atomizer could be useful in this respect.