Bipolar membranes were reported to split alcohol into alkoxide ions and H+; however, there is no direct evidence for ethanol splitting, i.e., the existence of ethoxide ions. This work uses ethanol for alcohol splitting test and H-1 NMR for the identification of ethoxide ions. According to the spectra analysis, the chemical shifts of proton H, delta 3.736-3.666 (q, 2H) and delta 1.255-1.209 (t, 3H) can only be ascribed to CH3CH2O-. Therefore, this work first proves ethanol splitting in bipolar membranes by detecting the existence of sodium ethoxide. To further extend the application of electrodialysis to non-aqueous systems (as in organic synthesis), membranes of better solvent-resistance are needed to be developed. (c) 2008 Elsevier B.V. All rights reserved.