Determination of trace amounts of gold in waste water by graphite furnace atomic-absorption spectrophotometry with preconcentration on trioctylphosphine oxide chemically modified tungsten wire matrix

Preconcentration on a trioctylphosphine oxide (TOPO) chemically modified tungsten wire matrix followed by graphite furnace atomic-absorption spectrophotometry measurement is described for the determination of trace gold in waste water. The TOPO modified tungsten wire matrix, after accumulating the gold, is placed in a graphite cup for direct atomization and measurement. Under the selected conditions, the absorbance is proportional to the concentration of gold over the range 0.4-18 ng/ml and the detection limit is 0.2 ng/ml. This method is sensitive and convenient. It has been applied to some waste waters with satisfactory results.