STUDIES OF HYDROGEN/DEUTERIUM EXCHANGE OF MONODEUTERIOPHENOL IN FUSED-SILICA CAPILLARY COLUMNS USING GAS CHROMATOGRAPHY MASS SPECTROMETRY

摘要

The hydrogen/deuterium (H/D) exchange process in fused-silica capillary columns was extensively studied using two old and two new columns. The compounds selected for this study were mixtures of phenol and monodeuteriophenol with different compositions. The factors controlling and influencing this phenomenon, such as heating rate and flow-rate variation as a function of residence time on the internal column-surface, were also evaluated. Temperature programming and isothermal analysis were performed for comparison. All studied factors proved that old fused-silica capillary columns exhibit sufficient activity to affect H/D exchange of monodeuteriophenol compounds, but the degree of exchange depends mainly on the position of ring deuteration. However, new columns were found to be less reactive toward H/D exchange and the percentage of exchange may be considered to be within the experimental error.