The Spark Source Mass Spectrography Using Graphite Pressed Electrodes of Powdered Sample

Abstract

The pressed electrode techniques using graphite perwder as a conducting suppdit material have been investigated to obtain favorable source conditions for quantitative analysis of powder samples by spark source mass spectrographic method. 1. Using the pressing tool which we have developed, a rod sufficiently strong to be clamped in the electrode holders could be formed from mixtures of graphite and sample in any ratio, so far as we tested with KCl, CdS, ZnCl2and GaAs. 2. The relative sensitivity, for example, of K to Cl in the graphite-KCl pressed electrodes was found strongly dependent on the spark gap width. However, comparatively reproducible sensitivity(relative standard deviation less than10per cent)could be obtained, provided that the spark gap could be easily kept at about100μ, with rf spark voltage at 40-60 KV, repetition rate at 100-300 per second and the graphite content larger than ca50per cent by weight. 3. A correction method for impurity elements contained in graphite powder used as support material was proposed.