Determination of trace and ultra-trace amounts of germanium in environmental samples by preconcentration in a graphite furnace using a flow injection hydride generation technique

This method involved flow injection (FI) hydride generation with subsequent trapping and electrothermal atomization in a graphite furnace pre-coated with palladium. Samples were propelled into the FI system and merged on-line with the tetrahydroborate reductant. Hydride and hydrogen gases evolved were separated from the liquid phase in a gas-liquid separator and transferred to a preheated (400C), palladium-coated graphite furnace for analyte collection. The analyte was then atomized at 2500C. Tolerance to interference effects in this hydride generation atomic absorption spectrometric (HGAAS) method was improved at high acidities (3 M hydrochloric acid). Germanium was thus determined at a sampling frequency of 18 per h with a detection limit of 0.004 ug per litre in 0.15 M hydrochloric medium and 0.03 ug per litre in 3 M hydrochloric acid medium using a 4.5 ml sample. Precisions (rsd) were 2 and 2.5 per cent, respectively, at 0.3 ug per litre (0.15 M hydrochloric acid) and 1.5 ug per litre (3 M hydrochloric acid) media. The method was successfully applied to the determination of germanium in garlic, tap water, ginseng and geological reference materials. There are 32 references.