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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Food Composition and Methods Development Laboratory » Research » Publications at this Location » Publication #91897


item Harnly, James - Jim

Submitted to: Spectrochimica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: This paper presents a theoretical consideration of a future instrument for graphite furnace atomic absorption spectrometry (GF-AAS). GF-AAS is commonly used in all fields of science for the determination of trace metals in complex samples. Conventional GF-AAS instruments now use a hollow cathode lamp and a photo multiplier tube (or single photo diode) and are very limited in the spectral and spatial information that they can acquire. This paper shows that with a continuum source, a high resolution echelle spectrometer, and a 2-dimensional array detector, considerably more information can be acquired. This results in far greater accuracy in computing the analytical absorbance and comes close to an absolute measurement which removes measurement variability between instruments. In theory, this new generation of instruments will have the ability for absolute analysis, i.e. determination of the analyte concentration without use of standards. This new generation of instruments can have significant impact on trace metal determinations in all fields.

Technical Abstract: The problem of absolute analyte detection is considered in this paper. It is shown that integration in absorbance, not in intensity is a prerequisite for absolute detection in atomic absorption spectrometry. A design for an atomic absorption spectrometer of the future is described which measures absorbance resolved in three key areas: wavelength, space, and time. Intensity must be measured with sufficient temporal, spatial, and spectral resolution to guarantee the accuracy of the computed absorbance. Technically, such measurements can be made simultaneously with a continuum source, a high resolution echelle spectrometer, and a two dimensional solid state array detector. All computed absorbances are fully background and stray light corrected. With such measurements, and a proper optical configuration, absolute analyte detection can become a reality and the possibility of absolute analysis becomes more obtainable.