Raman spectroscopy investigation of various saturated monoacid triglycerides

A study of the vibrational behavior of five saturated monoacid triacylglycerides is performed by Raman spectroscopy at room temperature in the 3100-500 cm−1 spectral range. The splitting of the CO stretching mode leads to conclude on the existence of two or three geometries of CO in the “knot” group OCO. The CO stretching mode seems to be a good tool for distinguishing the polymorphic forms of the studied triglycerides. The assignments of the different CH stretching modes are performed in the 1500-500 cm−1 spectral range. The I(2845)/I(2880) (in the CH stretching spectral region) and I(1445)/I(1296) intensity ratios (between the maximal intensity I(1445) of the CH2 scissoring mode and the maximal intensity I(1296) of the skeletal vibration of (CH2)n in-phase twist) seem to depend on the type of polymorphic forms of these molecules.