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Journal of the Brazilian Chemical Society

versión On-line ISSN 1678-4790

Resumen

WELZ, Bernhard et al. High-resolution continuum-source atomic absorption spectrometry: what can we expect?. J. Braz. Chem. Soc. [online]. 2003, vol.14, n.2, pp. 220-229. ISSN 1678-4790.  http://dx.doi.org/10.1590/S0103-50532003000200007.

A new instrumental concept has been developed for atomic absorption spectrometry (AAS), using a high-intensity xenon short-arc lamp as continuum radiation source, a high-resolution double-echelle monochromator and a CCD array detector, providing a resolution of ~2 pm per pixel. Among the major advantages of the system are: i) an improved signal-to-noise ratio because of the high intensity of the radiation source, resulting in improved photometric precision and detection limits; ii) for the same reason, there are no more 'weak' lines, i.e. secondary lines can be used without compromises; iii) new elements might be determined, for which no radiation source has been available; iv) the entire spectral environment around the analytical line becomes 'visible', giving a lot more information than current AAS instruments; v) the CCD array detector allows a truly simultaneous background correction close to the analytical line; vi) the software is capable of storing reference spectra, e.g. of a molecular absorption with rotational fine structure, and of subtracting such spectra from the spectra recorded for a sample, using a least squares algorithm; vii) although not yet realized, the system makes possible a truly simultaneous multi-element AAS measurement when an appropriate two-dimensional detector is used, as is already common practice in optical emission spectrometry; vii) preliminary experiments have indicated that the instrumental concept could result in a more rugged analytical performance in the determination of trace elements in complex matrices.

Palabras clave : continuum-source atomic absorption spectrometry; high-resolution atomic absorption spectrometry; spectral interferences; simultaneous background correction; three-dimensional spectrometry; thallium determination; sediment analysis.

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