Electrochemical mass spectrometry was used to study the adsorbates formed from 2-methyl propane in 85% phosphoric acid at 105 degreesC at platinum. The adsorbates backbone progressively goes stepwise from four carbons to one carbon, with some overlap as the potential becomes more positive. Carbon dioxide production is at its maximum when the electrode adsorbates consist primarily of four and three carbon adsorbates. 2-Methyl propane is quantitatively oxidized to carbon dioxide and water. (C) 2003 Elsevier Science B.V. All rights reserved.