of the measured intensity due to radiation scattering or molecular absorption, which is corrected in the same way. As measurement of total and background absorption, and correction for the latter, are strictly simultaneous (in contrast to LS AAS), even the fastest changes of background absorption, as they may be observed in ET AAS, do not cause any problem. In addition, as the same algorithm is used for background correction and elimination of lamp noise, the background corrected signals show a much better signal-to-noise ratio compared to the uncorrected signals, which is also in contrast to LS AAS. Background correction using a least-squares algorithm The above technique can obviously not correct for a background with fine structure, as in this case the absorbance will be different at each of the correction pixels. In this case HR-CS AAS is offering the possibility to measure correction spectra of the molecule(s) that is (are) responsible for the background and store them in the computer. These spectra are then multiplied with a factor to match the intensity of the sample spectrum and subtracted pixel by pixel and spectrum by spectrum from the sample spectrum using a least-squares algorithm. This might sound complex, but first of all the number of di-atomic molecules that can exist at the temperatures of the atomizers used in AAS is relatively small, and second, the correction is performed by the computer within a few seconds. The same algorithm can actually also be used to correct for direct line overlap of two atomic absorption lines, making HR-CS AAS the only AAS technique that can correct for this kind of spectral interference. See also Absorption spectroscopy Beer–Lambert law Inductively coupled plasma mass spectrometry Laser absorption spectrometry References Further reading B. Welz, M. Sperling (1999), Atomic Absorption Spectrometry, Wiley-VCH, Weinheim, Germany, . A. Walsh (1955), The application of atomic absorption spectra to chemical analysis, Spectrochim. Acta 7: 108–117. J.A.C. Broekaert (1998), Analytical Atomic Spectrometry with Flames and Plasmas, 3rd Edition, Wiley-VCH, Weinheim, Germany. B.V. L’vov (1984), Twenty-five years of furnace atomic absorption spectroscopy, Spectrochim. Acta Part B, 39: 149–157. B.V. L’vov (2005), Fifty years of atomic absorption spectrometry; J. Anal. Chem., 60: 382–392. H. Massmann (1968), Vergleich von Atomabsorption und Atomfluoreszenz in der Graphitküvette, Spectrochim. Acta Part B, 23: 215–226. W. Slavin, D.C. Manning, G.R. Carnrick (1981), The stabilized temperature platform furnace, At. Spectrosc. 2: 137–145. B. Welz, H. Becker-Ross, S. Florek, U. Heitmann