Evaluation of a pulsed EIMAC source for atomic-fluorescence spectrometry

An EIMAC xenon arc continuum source operated in the pulsed mode has been evaluated for potential use as a source of excitation in atomic-fluorescence spectrometry. The results were compared with those obtained with a similar lamp operated in the continuous-wave mode; little or no improvement was evident from this comparison. The lamp was found to be unstable in the pulsed mode, requiring the use of a rather large residual d.c. current in conjunction with a relatively low amplitude power-pulse in order to sustain the arc. Moreover, the pulsed source yielded a large background signal because of scattering of source-radiation in the flame; the background spectrum (with source "on") contained numerous large peaks due to fluorescence of molecular species in the flame and to irregularities in the spectral distribution of the pulsed lamp output transmitted to the signal detector by scatter.