Evaluation of a continuously variable impactor for use with flame atomisation

Abstract

A critical assessment has been made of the extent to which an impact cup or bead may be used to regulate sensitivity in flame atomic absorption and emission spectrometry, particularly with a view to increasing the useful working ranges of calibration graphs. The impactors were located on adjustable arms in front of the nebuliser capillary tip. The changes in sensitivity due to impactor position were examined over a range of capillary tip to impactor distances for manganese and copper for both absorption and emission. The results show that the two impactors affect the absorption and emission sensitivities to different extents. This observation may be explained in terms of measured changes in flame temperature and in the amount of water reaching the flame. Aerosol droplet size distributions were measured and related to the interference effects at different impactor distances.