Inverse gas chromatography (IGC) and sessile drop contact angle measurement were used to study the surface energetics of calcium carbonates from different sources and the effects of surface conditioning . A compilation of the results using these two methods to determine the apolar and polar nature of the surface is given . The results of the two analytical methods are summarized individually . IGC analysis provided a sensitive tool for detecting differences in surface energy attributed to variation in surface water, or by contamination with other chemisorbed species . Basic probes were used to characterize surface acidic sites. Acidic probes, however, were found too reactive with the calcium carbonate to en-
able a quantification of the surface basicity . Strong adsorption of acidic probes indicates the presence of a strong basic component at the surface . The susceptibility of the IGC method to misinterpretation retention data obtained from chemisorbed probes was also identified . Contact angle experiments were conducted on cleaved calcite samples using multiple wetting liquids and two techniques to separate the polar and apolar contributions of surface energy. The results demonstrate a strong interaction of water with the calcite surface and the reduction of total surface energy when the surface is treated with al-
kylketene dimer. A comparison of results from both methods is provided . Differences in the application of the results of the two methods to access the surface energetics are addressed . The importance of distinguishing between the thermodynamics of gas/condensed and condensed/condensed phase interactions when comparing the results from IGC and wetting experiments is also discussed . For calcium carbonate, the trends observed by the two approaches are consistent, although a defining link between the two was not established.