Determination of gold in waters by electrothermal atomic absorption spectrometry with preconcentration on a tungsten bar

The preconcentration of gold in water on tungsten bar followed by electrothermal atomic absorption spectrometry with a molybdenum tube atomizer is described. The optimal immersing time was 15 s. The best pH for gold adsorption was 3. Under optimal conditions, the detection limit was 1.6 pg mL(-1) (3S/N). The effects on the preconcentration of gold by large amounts of concomitants were evaluated. Even though 100 000-fold matrix elements existed in water, the gold absorption signal was not affected by the matrix elements. The method with preconcentration on tungsten bar was applied to the determination of gold in river and sea water.