Hybrid Rotating Arc-Tube Furnace Device for Microsolution Analysis

Abstract

A hybrid arc-furnace system using a magnetically rotated, concentric-electrode arc connected to a pyrolytic graphite tube furnace is described. The arc is formed between a 5-mm-i.d. graphite tube anode and a W/Th wire cathode. A 0.9-kG magnetic field from a ceramic permanent magnet causes the arc plasma to rotate at about 1.4 kHz, thus forming a diffuse plasma dome covering the end of the anode cylinder. A 10-mm-long ceramic tube connects the furnace to the arc anode. The graphite anode and graphite furnace are housed in the same chamber. Rotation around a horizontal axis allows the system to quickly convert between a sample loading position and a plasma discharge position. Detection limits for various metallic elements are in the ppb and sub-ppb range. Design features and performance data are presented.