Determination of trace amounts of carbon in high-purity iron by infrared absorption after combustion: Pretreatment of reaction accelerator and ceramic crucible

Pre-treatment procedures for analysis for determination of trace Carbon amo unts in high-purity iron was investigated Carbon in metal samples has been determined with an infrared absorption method after combustion. An analytic al sample with a mixed tungsten-tin as a reaction accelerator in a ceramic crucible is subjected to combustion in oxygen atmosphere. Contamination car bon species in the oxygen gas, the ceramic crucible and the accelerator cau se analytical blank value. The oxygen gas was purified. The ceramic crucibl e was heated at 1623 K for more than 20 min in ambient atmosphere. Moreover , the accelerator was heated in ambient atmosphere at 1003 K for 15 min wit h stirring it every 5 min during heating. Consequently, the carbon blank co uld be completely removed, and trace amounts of mu g.g(-1) level carbon in high-purity iron could be determined in the proposed method.