In this work, the speciation (i.e., 1DMA2P molecule as well as 1DMA2PH(+), HCO3- , and CO3 (2-) ions) for the CO2 reactive absorption of CO2 in aqueous 1-dimethylamino-2-propanol solution (i.e., into a 1DMA2P-H2O-CO2 system) was studied using the C-13 nulcear magnetic resonance (NMR) technique at a temperature of 301 K over the 1DMA2P concentration range of 0.52.0 mol/L and CO2 loading range of 01.0 mol CO2/mol amine. Also, in addition to other material conservation laws, a new criterion for selection of the protonation calibration curves, the charge balance of the 1DMA2P-H2O-CO2 system, was added in order to generate results with better accuracy. In addition, the equilibrium constants, K-1 and K-5, were also obtained using the NMR technique, which had good agreement with those from other works with absolute average deviations of 2.2% and 3.5%, respectively.