The exhaustive characterization of all components of our vaccine (VA-MENGOC-BC®), is a very important information to the new strategies of production and the best quality of it. Recently some regulatory authorities have recommended to remove thiomersal from vaccines altogether. In this paper we propose a disadsorption method for later chromatographic analysis of vaccine samples with or without thiomersal to know the possible antigenic variation. Three vaccine batches, stored between 2-8 °C, were studied at 0 time using different variants of disadsorption. We have demonstrated that solubilisation of the aluminium hydroxide by HCl to release the native vaccine complex is not possible and that the most efficient disadsorption method for the chromatographic analysis of VA-MENGOC-BC® is the following: the precipitate obtained from 3 mL of vaccine is diluted in 2 mL of phosphate buffer 5mM, pH 7,2-7,3, and allowed stand exactly 2 hours at 4°C. Afterwards, the samples were centrifuged and the supernatant collected. With this method we have obtained a 20% disadsorption of the sample. The result is very useful for showing the advantages of new formulations. [ABSTRACT FROM AUTHOR]