Determination of Cadmium in Water Samples by Electrochemical Hydride Generation Atomic Fluorescence Spectrometry Using Series Graphite Tubes as Electrolytic Cells under Constant Voltage

An electrochemical vapor generation (EcHG) system to determine the cadmium content using atomic fluorescence spectrometry has been established. The EcHG system uses two serially-connected graphite tubes as two electrolysis cells and an AC to DC power wall plug adapter with the constant voltage mode as a power supply. The system did not have an ion exchange membrane and only needed a pump to transport the feed solution and waste. Under these optimized conditions, the detection limit (3 sigma) and the relative standard deviation were 0.05 ng mL(-1) and 3.2%, respectively. The EcHG efficiency was 38.4 +/- 2.2%. The proposed technique has been successfully applied to determine the cadmium in three certified reference materials for environmental water and two drinking water samples.