The graphite furnace and its role in atomic spectroscopy

Abstract

The diversity of applications of the graphite furnace is extraordinary, encompassing the fields of physics, thermochemistry, spectroscopy and analytical chemistry. In this respect, the graphite furnace has been used on a continuous basis as a research tool for nearly a century. Following its introduction as an atomization source for atomic absorption spectrometry by L'vov in 1959, its role in atomic spectrometry expanded considerably to encompass analytical applications in emision, fluorescence, absorption and mass spectrometry. In addition to its conspicuous use as an atomization source in these areas, it is frequently employed as a vaporizer when used in the format of combined and tandem sources with other instrumentation. The unique physico-chemical micro-environment which can be attained within the graphite furnace has also been used to advantage in a number of investigations, including the determination of gas- and solid-phase diffusion coefficients of high-temperature metal vapours, the heats of sublimation of refractory metals, fundamental optical constants and the measurement of the heats of desorption of adatoms from high-temperature surfaces. The range of such applications remains to be more fully explored. The attractive features of this source, viz., the high atomization/vaporization efficiency, comparatively long atomic vapour residence times, controllable chemical and thermal environment and its ability to handle high dissolved solids content samples (</=100%) serve to ensure its place in analytical atomic spectroscopy for years to come.

Direct analysis of biological samples by total reflection X-ray fluorescence

“…Because of its high thermal stability, sodium chloride (mp 801 8C, bp 1413 8C) [44] cannot be readily eliminated in the pyrolysis stage of the atomization program. In order to minimize such inconvenience, Ediger resorted to the addition of ammonium nitrate to promote the formation of ammonium chloride [45]. The lower boiling point of such compound (subl.…”

“…340 8C) [44] would thus permit removal of the interference at lower pyrolysis temperatures. Though the latter is easily conducted in GFAAS, thanks to the intrinsic temperature control of the graphite furnace atomizer [45], the same is not applicable to TRXF. For a given compound to be properly used as a chemical modifier in TRXF, it must meet two main general requirements: (i) alter a physical-chemical property of the system (analyte, matrix and/or the reflector surface) according to the case and (ii) leave a thin film [9].…”