A Simple Technique for Coating Carbon Atomic Absorption Atomizer Components with Pyrolytic Carbon

Abstract

Recent literature is replete with evidence that carbon nonflame atomizers used for atomic absorption or atomic fluorescence analysis are improved by the use of pyrolytically coated graphite or vitreous carbon in lieu of the more common (and cheaper) forms of carbon. The reasons lie in the permeability of the usual spectroscopic graphites to gases and solutions. This permeability allows actual loss of sample atoms through the walls of the atomization chamber and shortens the effective residence time of atoms within the optical path. Analyte material from solutions partially absorbed into the graphite substrate before drying enters the optical path more slowly upon application of the atomization current than will material on the surface. This causes a broadening and lowering of the peak absorption signal.