A rapid and powerful method for the direct gas chromatographic analysis of alkanolamines; Application to ethanolamines

Summary

The problems of derivative gas chromatography of the alkanolamines have been discussed. It has been demonstrated that the difficulties of direct GC, inherent in the high adsorption affinity and strong retentive interaction of this class of compounds with silaceous supports and stationary liquids, can be overcome by using organic polymer beads, having weakly interacting surface. From a short column containing Tenax-GC under programmed temperature conditions, better than base line resolution of the three ethanolamines can be achieved in less than 8 minutes, as against about an hour by derivative GC and several hours by chemical methods, based on amine functionality. Elution properties, such as retention index and its temperature coefficient, have been determined on Tenax-GC for the ethanolamines. A boric acid precolumn is reported for the first time to completely subtract the alkanolamines. The relative response factors, which are required for precision analysis, have been found to make an interesting comparison for the ethanolamines and their derivatives. Under optimised PTGC conditions, a 4 ft Tenax-GC column has revealed the presence of six impurity peaks with fairly good resolution in a commercial sample of triethanolamine.