A device mounting platform apparatus having a reconfigurable biasing mechanism. More particularly, the invention provides for the extraction from human plasma or serum samples comprising vitamin D metabolites such as 1,25-dihydroxy vitamin D3, 25-hydroxy vitamin D2, and D3 from protein binding, removal of protein and phospholipids, and isolation of the metabolites using a combination of ion-exchange and Lewis acid mechanisms without the requirement to acidify the samples. The actions are implemented as methods within the object-oriented architecture. Placing step places the plate-like-shaped thin film member on the supporting member so that an opposite surface thereof faces the electrodes.