Barrier polymer films are characterized by very low sorption levels which can nevertheless vary by several orders of magnitude depending on the absorbed solvent. Quantitatively determining their sorption properties is a true challenge with key related applications in packaging or automotive industry. This paper describes a new automated desorption apparatus developed for analyzing multi-component sorption in barrier polymer materials. The main characteristics of this automated apparatus, coupling a desorption mini-oven with on-line chromatography, are discussed with respect to the strong technical limitations imposed by these particular polymer/solvents systems. A sensitivity of 1 mu g was easily obtained for the desorbate sample. Associated with a progressive rise in temperature of the polymer films, this very high sensitivity enabled to assess the sorption properties of two barrier materials (HDPE - high density polyethylene and EVOH -ethylene-vinyl alcohol copolymer) for fuel model mixtures (ethanol/i-octane/toluene) over a wide range of compositions typical for their use in multi-layer fuel tanks. (c) 2007 Elsevier B.V. All rights reserved.