Technique for determination of accurate heat capacities of volatile, powdered, or air-sensitive samples using relaxation calorimetry

Abstract

We introduce a four-step technique for the accurate determination of the heat capacity of volatile or air-sensitive samples using relaxation calorimetry. The samples are encapsulated in a hermetically sealed differential scanning calorimetry pan, in which there is an internal layer of Apiezon N grease to assist thermal relaxation. Using the Quantum Design physical property measurement system to investigate benzoic acid and copper standards, we find that this method can lead to heat capacity determinations accurate to +/- 2% over the temperature range of 1-300 K, even for very small samples (e.g., < 10 mg and contributing ca. 20% to the total heat capacity). (c) 2006 American Institute of Physics.