Quantitative Production of H₂ by Pyrolysis of Gas Chromatographic Effluents

Abstract

Hydrogen gas can be produced quantitatively from nanomole amounts of organic H in continuously flowing gas streams. The system described here is suitable for use in isotope-ratio-monitoring mass spectrometric systems and is based on a pyrolysis reactor consisting of a graphitized alumina tube heated to 1450 °C. Methane forms as an intermediate product at temperatures above 750 °C, but, for all tested analytes, yields of H2 were quantitative at temperatures between 1430 and 1460 °C, provided residence times in the reactor were greater than 300 ms. Quantitative yields of H2 were obtained for all components of a homologous series of n-alkanes (C15 to C30). Analyses of low-molecular-weight alcohols demonstrated that O-bound H was also quantitatively converted to H2 and, thus, that H2O, if formed, was quantitatively reduced to H2.