Activity coefficients at infinite dilution (gamma(infinity)(13)) have been determined for 27 solutes, viz, water and organic compounds (n-alkanes, cycloalkanes, 1-alkenes, 1-alkynes, aromatics, alcohols, and ketones) in the ionic liquid Ammoeng 100, by gas-liquid chromatography at four different temperatures, T = (308.15, 313.15, 323.15, and 333.15) K. Columns with different phase loadings (20 to 24)% of the ionic liquid in the stationary phase were employed to obtain gamma(infinity)(13) values at each temperature investigated. Partial molar excess enthalpies at infinite dilution (Delta H(1)(E infinity)) were calculated for the solutes from the temperature dependency relationship of the In(gamma(infinity)(13)) values for the temperature range in this study. The uncertainties in the determinations of the gamma(infinity)(13) and Delta H(1)(E infinity) values are 6% and 10%, respectively. Selectivity values at infinite dilution (S(ij)(infinity)), have been computed from the gamma(infinity)(13) values to assess the potential candidacy of the Ammoeng 100 ionic liquid for the separation of alkane/alcohol mixtures. The results from this study have been compared to those available for several ionic liquids from previous investigations. (C) 2011 Elsevier Ltd. All rights reserved.