Abstract
Tungsten, molybdenum, and tantalum were tested for the ribbon materials of the atomizer in metal flameless atomic absorption spectrometry. Effects of ribbon materials on the heating rate of the atomizer, shape of the signals, atomizing temperature-absorbance relations, and the time of peak appearance were studied. Sensitivities and repeatabilities were compared among these ribbon materials for the determination of zinc, copper, manganese, nickel, cobalt, and iron. The ribbons had boat-shaped indentations to accomodate the sample (<25μl), and were heated by an electric current from a controlled voltage, high current AC source with a maximum heating rate of 4 °C/ms. The three ribbon atomizers gave practically identical sensitivities and repeatabilities for zinc, manganese, and copper. For cobalt and nickel, the highest sensitivity and the best repeatability were obtained with the tungsten ribbon. The tailing of the absorption peak signal was observed for cobalt and nickel with tantalum and molybdenum ribbons. An interaction between the analyte metals and the ribbons was suggested for the low sensitivity and the poor repeatability of these elements with tantalum and molybdenum ribbons. The average lifetime of all ribbons when used at about 2100°C was 500 determinations or more.
