Abstract

The memory effects of mercury, gold and silver are eliminated by the use of sulfur containing complexing agents. In low concentrations (1 µg ml⁻¹) of mercury and gold, the addition of 2% L-cysteine gives wash-out times of less than 1 min for both elements. At higher concentrations of gold and mercury, and at low concentrations of silver, the reagent is less effective. Thiourea, at a concentration of 1%, eliminates the memory effects of silver, also giving wash-out times of approximately 1.5 min. The use of thiourea with higher concentrations (100 µg ml⁻¹) of mercury and gold delivers wash-out times of 1 min and 2 min, respectively. In a matrix similar to that found in many samples, the wash-out time for gold is less than 3.5 min and less than 2 min for mercury.