CERAMIDES CHOLESTEROL MIXTURES AS CHARACTERIZED BY FT RAMAN-SPECTROSCOPY/

Ceramides IV, hydrated ceramides IV and ceramides/cholesterol mixtures were studied by FT Raman spectroscopy and differential scanning calor imetry (DSC). The temperature-dependence of the conformationally sensi tive bands in the CH, stretching region was used to estimate the degre e of order of hydrocarbon chains in terms of the relative population o f trails and gauche conformers. The temperature and width of the phase transition, derived from Raman data, are similar to those from the DS C studies. The addition of both cholesterol and water lowers the phase transition temperature and broadens the transition range.