Trends and perspectives of flow injection/sequential injection on-line sample-pretreatment schemes coupled to ETAAS

Flow injection (FI) analysis, the first generation of this technique, became in the 1990s supplemented by its second generation, sequential injection (SI), and most recently by the third generation (i.e., Lab-on-Valve). The dominant role played by FI in automatic, on-line, sample pretreatments in recent decades is amply demonstrated by the large number of publications to which it has given rise. Among these, its hyphenation with electrothermal atomic absorption spectrometry (ETAAS) is one of the most attractive sub-branches because of the high sensitivity of ETAAS instruments for metal species. After a decade of development, it is apparent from the literature that coupling FI sample pretreatment with ETAAS remains most dynamic in the new millenium; meanwhile, it is exciting to note that some novel trends associated with this subject have also emerged. The aim of this mini-review is thus to illustrate the state-of-the-art progress in implementing miniaturized FI/SI systems for on-line separation and preconcentration of trace metals with detection by ETAAS since 2000. We also discuss future perspectives in this field.