Preconcentration technique for manganese by adsorption onto a tantalum wire for tungsten tube atomizer electrothermal atomization atomic absorption spectrometry

Abstract

A preconcentration technique for manganese in water samples by adsorption on a tantalum wire was investigated for tungsten tube atomizer electrothermal atomization atomic absorption spectrometry. After preconcentration, the tantalum wire was directly inserted into the tungsten tube atomizer. In the preconcentration (adsorption) process for manganese, the optimal immersion time was 60 sec and the best pH was 9. Under the optimal conditions, the detection limit for manganese by the tantalum wire preconcentration method was 6.3 pg mL−1 (3S/N) and the relative standard deviation was 7.6%. The influences of concomitants on the preconcentration of manganese were evaluated. Even though 103 to 104-fold excess of matrix elements existed in aqueous solution, the manganese absorption signal was not significantly affected by the matrix elements. The method with preconcentration on a tantalum wire was applied to the determination of manganese in river waters and proved to be sensitive, simple, and convenient. Because this preconcentration method can be utilized in the in-situ treatment of trace manganese in environmental water samples, it was unnecessary to carry the water samples to the analytical work place. The technique was shown to be useful for the determination of manganese in environmental water samples at 0.1–1 g L−1 levels.