Abstract
The effects of cryoprotectants (sugars and polymers) on the eutectic crystallization of NaCl/water systems were studied by differential scanning calorimetry (DSC) and broad-line pulsed NMR. Thermal analysis of frozen NaCl solutions showed a melting peak of eutectic NaCl/water systems at around -21°C. The addition of various cryoprotectants inhibited the eutectic crystallization of the NaCl solution. The concentrations of polymers (dextran, polvinylpyrrolidone and Ficoll) required to inhibit eutectic crystallization were slightly higher than those of sugars (glucose, sucrose, trehalose and lactose). The proportions of liquid-phase protons present in frozen H2O and D2O sulutions, determined by broad-line pulsed NMR, showed that the addition of sugar inhibits eutectic crystallization of NaCl/water systems through the formation of an amorphous mixture containing NaCl, sugar and water between the ice crystals.
