Comparison of bismuth atomic lamps for a non-dispersive atomic fluorescence spectrometry

Abstract

The performance of two types of radiation sources – an electrodeless discharge lamp (EDL) and a boosted discharge hollow cathode lamp (Superlamp) – for atomic fluorescence spectrometry (AFS) was studied and compared using bismuth as a model analyte at 222.8 and 223.1 nm fluorescence lines. Hydride generation was used for analyte introduction to a miniature diffusion flame where the generated bismuthane was atomized. An in-house assembled non-dispersive atomic fluorescence spectrometer was adjusted so that either of the sources could be employed. The optimization of the radiation sources at chosen 40 Hz modulation rate included a duty cycle and applied currents (primary and boost), in addition to proper focusing on the flame atomizer. With optimum operation parameters the sensitivity achieved with the EDL was around an order of magnitude higher than that with the Superlamp, in agreement with the higher radiation intensity measured by an optical power meter and resulting limits of detection of 1.5 pg and 11 pg, for the EDL and the Superlamp, respectively.