2009 Volume 58 Issue 5 Pages 393-397
A new improved double-chamber electrothermal vaporization (ETV) system has been designed. An inner chamber made of quartz glass was attached with an inlet port to an inductively coupled plasma (ICP) torch. The inner chamber has an important role to introduce metal vapor in a 1.0 kW argon ICP. Ten microliters sample aliquots were dried at 90°C and subsequently heated at 1300°C on a tungsten boat furnace. The released vapor was swept into the ICP source through PTFE tubing and the inner chamber by 0.6 L min−1 H2 (7%) - Ar carrier gas. The performance parameters of ETV-ICP-AES, such as the temperature program, gas flows and position of the inner chamber, were evaluated by using a cadmium standard solution. Under the optimized stop and flow experimental conditions, the best attainable detection limit at Cd I 214.43 nm line was 0.2 ng mL−1 with linear dynamic ranges of 10 to 10000 ng mL−1 for cadmium without modifiers. The instrumental precision, expressed as the relative standard deviation (RSD) from ten replicate measurements of 10000 ng mL−1 for cadmium by ETV-ICP-AES, was 0.85%. The detection limit and RSD were improved by 3 times over that reported by Okamoto. The present method has been applied to the determination of cadmium in water and plant samples.
