Page 56 - An Introduction to Analytical Atomic Spectrometry - L. Ebdon
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Figure 2.16
Background correction in action. (Top) background due to spraying chromium blank.
(Bottom) determination of Pb in Cr.
current, then atomic and molecular absorption by the analyte and interferents in the atom cell will
occur. If, however, the lamp is pulsed periodically to much higher currents, self-absorption in the lamp
prevents virtually all atomic absorption in the atom cell, but leaves the molecular absorption. The
corrected atomic absorption signal may therefore be obtained by subtraction. This method of
background correction, although popular and successful for a while, does lead to accelerated wear of the
hollow cathode lamps.
Q. How can the interference of AA measurements by AE signals be removed?
Q. What are the advantages in AAS of (i) modulation, (ii) double-beam systems and (iii) background
correction?
