Simultaneous determination of bismuth and tellurium in steels by high power nitrogen microwave induced plasma atomic emission spectrometry coupled with the hydride generation technique.

An annular-shaped, high power nitrogen microwave induced plasma (N(2)-MIP) produced at atmospheric pressure by an Okamoto cavity, as a new excitation source for atomic emission spectrometry (AES), has been used for the simultaneous determination of bismuth and tellurium in steels with the hydride generation method. Under the optimized experimental conditions, the best attainable detection limits at the Bi I 195.389 nm and Te I 200.200 nm lines were 110 and 86 ng/ml for bismuth and tellurium, respectively. The linear dynamic ranges for bismuth and tellurium were 300 to 30,000 ng/ml. The presence of several diverse elements was found to cause a more or less depressing interference with the proposed technique. When bismuth and tellurium in steels were determined, a large amount of Fe(III) in the solution caused a severe depressing interference, while the presence of Fe(II) showed little or no significant interference. Of the several interference-releasing agents examined, l-ascorbic acid was found to be the most preferable to reduce Fe(III) to Fe(II) prior to hydride generation. The concentrations of bismuth and tellurium in steels were determined by the proposed technique. The results obtained by this method were in good agreement with their certified values.