Atomic-Fluorescence Spectroscopy (AFS)
Introduction
Atomic fluorescence is the optical emission
from gas-phase atoms that have been excited to higher energy levels by
absorption of electromagnetic radiation. The main
advantage of fluorescence detection compared to
absorption
measurements is the greater sensitivity achievable because the fluorescence
signal has a very low background. The resonant excitation provides selective
excitation of the analyte to avoid interferences. AFS is useful to study
the electronic structure of atoms and to make quantitative measurements.
Analytical applications include flames and plasmas diagnostics, and enhanced
sensitivity in atomic analysis. Because of the differences in the nature
of the energy-level structure between atoms and molecules, discussion of
laser-induced fluorescence (LIF) from molecules is
found in a separate document.
Instrumentation
Analysis of solutions or solids requires that the analyte atoms be desolvated,
vaporized, and atomized at a relatively low temperature in a heat pipe,
flame, or graphite furnace. A hollow-cathode
lamp or laser
provides the resonant excitation to promote the atoms to higher energy
levels. The atomic fluorescence is dispersed and detected by monochromators
and photomultiplier tubes, similar to atomic-emission
Auf diesem Webangebot gilt die Datenschutzerklärung der TU Braunschweig mit Ausnahme der Abschnitte VI, VII und VIII.