[Determination of gold in geological sample by inductively coupled plasma mass spectrometry after carbon nanofibers separation and preconcentration].

A novel method for the determination of Au by inductively coupled plasma mass spectrometry (ICP-MS) is described. Au can be separated and preconcentrated with a micro-column packed with carbon nanofibers as an adsorption material. The adsorption and elution behaviors of Au3+ on carbon nanofibers were systematically investigated under dynamic conditions. The experimental results showed that the studied ions can be adsorbed quantitatively at pH 2.0, and the analytes adsorbed on the column can be eluted with H2NCSNH2-HCl solution at pH 1.0. Under the optimum conditions, the detection limits for Au is 0.15 ng x mL(-1), and the relative standard deviation (RSD) is 8.5% (n = 6). The proposed method has been applied to the determination of trace Au in geological standard material with satisfactory results.

[Slurry sampling for direct determination of trace cadmium in amber by graphite furnace atomic absorption spectrometry].

A method for the direct determination of trace cadmium in amber by graphite furnace atomic absorption spectrometry (GFAAS) with slurry sampling was described. Palladium nitrate was used as a matrix modifier to eliminate the interference. Slurry stability and the influences of the matrix modifier, ashing/atomization temperature and coexistent ions on analytical signals were investigated in detail. Under the optimized experimental conditions, the detection limit of this method was 9.4 ng x g(-1) with a precision of 6.1%.