Use of modifiers with metal atomizers in electrothermal AAS: a short review

The evolution of chemical modifiers for Mo and W atomizers is slowly progressing, based mainly on trial and error experimentation. Despite repeated use of some chemical compounds, such as thiourea for Mo atomizers, at this point there is no panacea similar to the Pd+Mg mixture used widely in graphite furnace atomic absorption spectrometry. Clearly, the chemical processes involved during atomization from a metal atomizer differ significantly from those occurring in a graphite tube, so successful graphite modifiers may not be readily adapted to metal atomizers. As a result, the analyst must begin anew with the evaluation of many potential modifiers in hopes of finally arriving at some universal solution. The purpose of this review, with 62 references, is to describe that journey to date, and to point out some promising paths that may lead to future success: such as the development of permanent chemical modifiers for W and Mo electrothermal atomizers.