The invention relates to a method for identifying in a sample molecules with the capacity to bind to the different members of a molecule library, wherein the molecules which are in the sample are fractionated based on a physicochemical property of the sample and subsequently transferred from the support in which said molecules have been separated to a second support in which the different members of the molecule library are grouped into microarrays such that they uniformly coat the surface of the support. This technique is especially interesting for the identification in a sample of glycoproteins with affinity for a lectin library as well as for the identification of compounds capable of modulating the glycosylation of proteins and for the rapid characterization of alterations in the glycosylation pattern of a sample of proteins, which can be useful in the diagnosis of diseases in which there are alterations in cell glycosylation.