In this work, compositions of the gas phase in equilibrium with hydrate and aqueous solution for the CO2+N-2+tetra-n-butylammonium bromide (TBAB)+water systems have been measured and are reported. The gaseous feeds of CO2 (0.151/0.399/0.749 mole fraction) +N-2 (0.849/0.601/0.251 mol fraction) in the presence of 0.05 and 0.30 mass fractions TBAB aqueous solutions have been studied herein. An apparatus comprising a high pressure equilibrium cell as the main part has been employed for performing the measurements following the isochoric method combined with gas chromatography technique. The range of conditions for the measurements are (275.15 to 289.21) K and (0.581 to 19.085) MPa. As a result, significant change of CO2 concentration in the gas phase is observed under hydrate stability conditions. (C) 2012 Elsevier Ltd. All rights reserved.