a method for capturing psa and its molecular forms that may be in a fluid biological material including the steps of : preparing a chromatographic column by placing a thiophilic gel in a column where the thiophilic gel is formed from a water insoluble polymer where the surface of the gel is provided with thiophilic moieties that bind psa in the presence of an adsorption liquid but that will release psa upon elution with an eluting liquid , said thiophilic moieties comprising a two part structure wherein one part can be characterized as a hydrophilic electron acceptor and the other part is sulfur which acts as an electron donor ; selecting a sample of a fluid biological material to be tested for psa and its complexes ; introducing the sample into the column ; eluting the sample through the column ; rinsing the column with adsorption liquid to remove materials that are unbound to the thiophilic gel ; and capturing psa and its complexes in eluted column fractions .