High resolution calorimeter for the investigation of melting in organic and biological materials

Abstract

A high-resolution, high-sensitivity ac calorimeter has been developed to investigate the ''melting'' of organic and biological materials. The heart of this system is a simple yet very versatile sample cell which can be reused. High-temperature-resolution studies of the melting of n-octadecane and tert-butyl alcohol indicate interesting premelting and prefreezing phenomena in the specific heat capacity in these substances. With pure dipalmitoyl L-alpha-lecithin (DPL), in water, we obtain a very sharp (FWHM=0.38 degrees C) first-order phase transition showing no pretransition broadening or post-transition tails in the specific heat curves near the 41.2 degrees C transition point.