Quantification of low levels of amorphous content in maltitol

A method for the quantification of low levels of amorphous content of maltitol with hyper-DSC (high speed DSC) was developed. The method is based on the fact that the change of specific heat (ΔCp) at the glass transition is linearly proportional to the amorphous content. Twelve synthetic mixtures with various degrees of crystalline and amorphous maltitol were prepared. ΔCp was determined at both fictive and half point glass transition temperature and equations for ΔCp as a function of amorphicity were calculated. The limit of detection (LOD) and the limit of quantification (LOQ) values were 0.313% (amorphicity) and 1.04% for fictive temperature and 0.107 and 0.358% for half point temperature, respectively. In addition, instrumental sensitivity and detection limit were determined. The calculated LOD value for a heating rate of 100 °C min−1 and a 10 mg sample was 0.001%. It was noticed that the preparation of amorphous maltitol was the weakest point in the quantification of low amorphous levels in maltitol. The influence of annealing time and the heating/cooling rate on the ΔCp was studied. The influence of moisture was discussed.