The partitioning of acetone to different types of ice and snow between 198 and 223 K

Abstract

The air - ice partitioning of acetone to four different laboratory ice and natural snow samples was investigated at a surface coverage between 0.1 and 6% and temperatures between 198 and 223 K using a chromatographic column coupled to an atmospheric pressure chemical ionization mass spectrometer. The adsorption enthalpy and entropy were obtained from the temperature dependence of the measured partitioning coefficient. No significant difference was found among the four ice and snow samples substantially differing in crystallinity and chemical composition. An average adsorption enthalpy of 52 ± 2 kJ/mol and a standard adsorption entropy of -96 ± 16 J/(mol K) was obtained. A short outlook on partitioning coefficients under atmospheric conditions is given, and the adsorption mechanism is discussed based on the adsorption entropy and enthalpy found. Copyright 2004 by the American Geophysical Union.