A burner, which stabilizes near-one-dimensional low-temperature flames at atmospheric pressure, was designed to access the combustion regime near 1500 K for quantitative species diagnostics. Combustion temperatures between 1300 and 1800 K in argon-diluted methane-oxygen flames were achieved by preheating the burner and adapting the inert gas flow. Mass spectrometry with electron ionization was used to determine mole fractions profiles of reactants, products, and intermediates. Combustion parameters were varied including stoichiometry, diluent mole fraction and preheat temperature. Mole fraction profiles resemble those taken in regular premixed flat flames. A number of C-1- and C-2-intermediates as well as some oxygenated species were identified. Higher-mass species (m/z > 42) were not detected in the low-temperature methane-oxygen flames which contain 90% argon in the cold gases. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.