Experimental investigation of electrodeless discharge lamps as excitation sources for atomic fluorescence flame spectrometry

Abstract

Experimental details of constructing electrodeless discharge tubes are given. The electrodeless discharge tubes are evaluated with respect to design and construction of an optimum source for use in atomic fluorescence flame spectrometry. By means of a statistical evaluation of data, it is shown that source intensities useful for the production of atomic fluorescence are directly related to lamp diameter, gas fill pressure, and form of element (metal or metal iodide) but are independent of the weight of metal or metal iodide introduced into the lamp. The optimum lamp diameter, gas fill pressure, and form of the element for production of analytically useful electrodeless discharge tubes and the spectral characteristics of the resonance lines produced by several electrodeless discharge tubes are given in tabular form. Problems encountered in the production of analytically useful sources for a number of elements are discussed. Resonant cavities and directional antennas as means of coupling microwave power into metal electrodeless discharge tubes are compared. For the studies presented here, the “A” type antenna with a quartz jacket for insulation around each source proved to give the greatest atomic fluorescence signals. Limits of detection for sixteen metals and analytical curves for fourteen metals excited by electrodeless discharge tubes in atomic fluorescence flame spectrometry are given to indicate the analytical utility.