Gold volatile compound generation: optimization, efficiency and characterization of the generated form
Abstract
The generation of an analytically useful volatile form of Au has been studied. The flow injection generation was performed in a dedicated generator consisting of a special mixing apparatus and gas-liquid separator design in the presence of surfactants (Triton X-100, Antifoam B) and diethyldithiocarbamate.
The on-line atomization in the quartz tube multiatomizer for atomic absorption (AAS) detection has been employed as the convenient atomization/detection means. The optimization of generation and atomization conditions resulted in an analytical procedure yielding the detection limit of 17 ng ml(-1) and a very good long range reproducibility of the analytical signal.
A 198,199 Au radioactive indicator of high specific activity together with AAS measurements was used to track quantitatively the transfer of analyte in the course of generation and transport to the atomizer and to determine the generation efficiency of 11.9 +/- 0.1% at the Ar carrier flow rate optimized for the multiatomizer of 240 ml min(-1). The efficiency was twice as high at the Ar carrier flow rate of 600 ml min(-1).
In situ trapping in GF for AAS was explored as an alternative to the on-line atomization. The detection limit of 3.0 ng ml(-1) was achieved even though the Ar flow rate optimum for trapping (115 ml min(-1)) was too low for efficient generation: the overall efficiency of generation and trapping was 1.11 perpendicular to 0.03%.
Transmission electron microscopy measurements proved the presence of Au nanoparticles of diameter of approximately 10 nm and smaller transported from the generator by the flow of carrier Ar.