Mono-d-alpha-tocopheryl polyethylene glycol 1000 (TPGS 1000) and di-TPGS 1000 were prepared from the synthesized TPGS 1000 mixture. The key separation step was performed by a Simulating Moving Bed chromatographic process. The chemical structures and molecular weight distrubution were characterized by H-1-NMR and MALDI-TOF mass spectroscopy. NMR and MALDI-TOF MS data confirmed the occurrence of di-TPGS. Both NMR and MALDI-TOF MS results showed the degree of polymerization of the two esters and the molecular mass. The melting temperatures of the two polymers were investigated by DSC and the thermal decomposition temperatures have been determined by TGA. The melting temperatures of the two esters were 33 and 15 degrees C, separately. And the two separated TPGS esters exhibited different thermal decomposition courses. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 3026-3033, 2011