Thermal phase transitions of agarose in various compositions: a fluorescence study.

The effect of agarose content on thermal phase transitions of the agarose gels was investigated by using Steady State Fluorescence (SSF) method. Scattered light, I(sc) and fluorescence intensity, I(fl) were monitored against temperature during heating and cooling processes to investigate phase transitions. Two regions were observed during the heating and cooling processes. At the high temperature region, double helix to coil (h-c) transition took place. However, during the cooling process coil to double helix (c-h) transitions occurred at low temperature region. Transition energies were determined using the Arrhenius treatment, and found to be strongly correlated with the agarose content in the gel system. Transition temperatures were determined from the derivative of the sigmoidal transition paths and found to be increased by increasing agarose content in both cases.