Electrothermal atomic absorption and preconcentration device

摘要

A method and an apparatus for the electrothermal atomic absorption spectrophotometric determination of a variety of elements which are affected by severe matrix interferences is disclosed. In one aspect the method relies upon the electrodeposition of the element to be analysed directly into the inner surface of a graphite tube disposed in the furnace assembly. In a second aspect of the method, a metal protective of the inner surface of the graphite tube is either electrodeposited prior to or concurrent with the deposition of the element to be analysed. The apparatus of the invention comprises an atomic absorption spectrometer incorporating a graphite furnace assembly; an automatic sample loader (14, 15) having an electrically conductive capillary tube (13) adapted to hold an aliquot of a sample or other solution; a pyrolytic graphite tube (10) disposed within the furnace assembly of the atomic absorption spectrophotometer so as to permit the drying, if required, ashing and atomisation of a sample contained therein and having an opening (11) adapted to permit the entry of the capillary tube (13) therein; and a source of potential (16) connected to the capillary tube (13) so as to form an anode and to the pyrolytic graphite tube (10) so as to form a cathode.