Utilization of electrodeposition for electrothermal atomic absorption spectrometry determination of gold

Gold was determined by electrothermal atomic absorption spectrometry after electrochemical preconcentration on the graphite ridge probe used as a working electrode and sample support. The probe surface was electrochemically modified with Pd, Re and the mixture of both. The electrolysis of gold was performed under galvanostatic control at 0.5 mA. Maximum pyrolysis temperature for the probe surface modified with Pd was 1200 °C, with Re 1300 °C. The relative standard deviation for the determination of 2 μg l− 1 Au was not higher than 5.6% (n = 8) for 2 min electrodeposition. The sensitivity of gold determination was reproducible for 300 electrodeposition and atomization cycles. When the probe surface was modified with a mixture of Pd and Re the detection limit was 31 ng l− 1 for 2 min electrodeposition, 3.7 ng l− 1 for 30 min, 1.5 ng l− 1 for 1 h and 0.4 ng l− 1 for 4 h electrodeposition, respectively. The procedure was applied to the determination of gold in river water samples. The relative standard deviation for the determination of 2.5 ng l− 1 Au at 4 h electrodeposition time at 0.5 mA was 7.5%.