Abstract
Germanium is determined in aqueous matrix at the part-per-trillion level by a combination of hydride generation, graphite furnace atomization, and atomic absorption detection. The germanium is reduced by sodium borohydride to germane (GeHSUB-4 ), stripped from solution by a helium gas stream, and collected in a liquid-nitrogen-cooled trap. It is released by rapid heating of the trap and enters a modified graphite furnace which is synchronized to reach the analysis temperature of 2600 C before arrival of the germane peak. The atomic absorption peak is recorded and electronically integrated. The absolute detection limit is 140 pg of germanium. The concentration limit of detection is 0.56 ng/l for a 250-ml sample.The dynamic range of the method spans 3 orders of magnitude. The precision of the determination is 8% when peak absorbance is used; by peak integration in the nanogram range, the precision is 4%. Results of the analyses of natural waters are presented.