Determination of chromium in river waters by electrothermal atomic absorption spectrometry with preconcentration on a tantalum wire

The preconcentration of chromium on tantalum wire followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The preconcentration is accomplished by adsorbing chromium on a tantalum wire. The optimal immersion time was 3 min. The best pH for chromium adsorption was 3. Under optimal conditions, the detection limit was 15 pg mL–¹(3×S/N). The effects on the preconcentration of chromium by large amounts of contaminants were evaluated. Even though matrix elements existed in 10³–10⁴-fold excess in water, the chromium absorption signal was not affected by the matrix elements. The method with preconcentration on tantalum wire was applied to the determination of chromium in river water.