In liquid elution adsorption chromatography (L.E.A.C.), multicomponent eluents are commonly used to provide the exact eluent strength necessary for separation. When certain types of detectors are used to monitor the column outlet, spurious peaks are observed. A model has been set up to account for such behaviour and computer simulation was used to permit the performance of ideally controlled ‘experiments’ over a wide range of operating conditions. The results of the computer study were verified experimentally, both qualitatively and quantitatively. It was found that in certain cases the quantitative error introduced by these displacement peaks could amount to as much as 30% of the correct result. The significance of this is discussed with relation to quantitative work in liquid chromatography.