A method is disclosed for the differentiated sequestration of substances of different substance groups A and B in a sulfated and/or sulfonated hydrogel while simultaneously releasing substances of substance group A or B from the sulfated and/or sulfonated hydrogel into the biofluid. The sulfated and/or sulfonated hydrogel is selected from a group of hydrogels of Type 1, 2, 3, 4 and consist of uncharged and charged components. The charged components are characterized by calculating the number of sulfated or sulfonated groups per repeat unit divided by the molecular mass of the repeat unit, for each of Type 1 2 3 and 4. The swollen hydrogels have a concentration of sulfated or sulfonated groups in mmol/ml for Type 1, Type 2, Type 3 and Type 4. The concentration of substances of each substance group A and group B in the biofluid is influenced by the selection of the type of hydrogel.