Depolarisation thermocurrents in frozen aqueous solutions of glucose

The dielectric behaviour of frozen aqueous solutions of glucose was studied by the depolarisation thermocurrent (DTC) method in the temperature range 85-250K and over a wide range of concentrations (0.005-1.5 mol. litre -1 ), to obtain information on the state of water in the solutions. Two predominant peaks were observed at temperatures of about 125-130 and 225K, respectively. The low-temperature DTC peak was studied in detail, using several techniques offered by the DTC method. The peak was attributed to polarisation of free and hydration H 2 O molecules. The results show the existence of a continuous transition from hydration to free H 2 O molecules in solutions with molar solute concentrations up to about 0.7 mol. litre -1 , and the presence of only hydration H 2 O molecules in solutions with higher concentrations.