THERMOGRAVIMETRIC STUDY OF THE DEHYDRATION PROCESS OF ALPHA-CYCLODEXTRIN - COMPARISON BETWEEN CONVENTIONAL AND HIGH-RESOLUTION TGA

The aim of resolving the several steps of alpha-cyclodextrin (alpha CD ) dehydration has been pursued, both by conventional (constant heating rate) and high-resolution TGA. It is shown that a careful selection o f the experimental parameters (heating rate and resolution parameters) in both TGA modes leads to very similar results. In particular, it ha s been demonstrated that four steps can be resolved in the TGA curves. Stage 1 is due to surfacial water release. Stages 2 and 3 correspond to the water present in the interstices. Stage 4 individuates the wate r inside the alpha CD cavity. (C) 1998 Elsevier Science B.V.