1. Freezing of DNA Gel and Separation of Tris-HCl-H_2O Eutectic(Papers presented at the 36th Annual Meeting, April, 1990, Tokyo)

Abstract

Freezing processes of Tris-HCl buffer solutions and DNA gels were investigated by low frequency Raman spectroscopy and differential scanning calorimetry (DSC). The eutectic made of Tris-HCl and water are formed during the heating process, only after the solution undergoes glass transition below -50℃ during the previous cooling. DNA gels prepared by dissolving DNA in a Tris-HCl buffer solution freeze differently from salt free DNA gels. We found that when DNA gels with Tris-HCl are kept at -30℃ during heating after the previous cooling below -50℃, the eutectic of Tris-HCl and water grows slowly and separates from DNA.