Chemical vapor generation—electrothermal atomic absorption spectrometry: new perspectives

Volatile species of Ag, Cu, Cd, and Zn were generated at room temperature by the addition of sodium tetrahydroborate (III) to an acidified solution of the analytes. The vapor-phase species were rapidly transported to a pre-heated graphite tube, the surface of which was previously treated with Ir as a permanent chemical modifier. The volatile species were trapped at the Ir treated tube surface, and the further heating of the furnace permits their determination by atomic absorption spectrometry. A univariate approach was used to achieve optimized conditions and derive the figures of merit. The limits of detection based on a 3σb criterion were 10 (1); 0.006 (6×10−4); 28 (2.8) and 1.1 (0.11) ng (μg ml−1) for Ag, Cd, Cu and Zn, respectively. Precision of replicate measurements was typically approximately 10% R.S.D. Using a transfer line as short as possible should minimize losses of analyte during the transport to the graphite furnace. The overall efficiency of the volatile species generation and trapping process estimated for silver was 13%.