Abstract: Provided herein is a combination comprising: an optically transparent substrate, a sample that comprises biological analytes, and a layer of a conductive organic polymer. In this combination, the layer of polymer may be between the sample and the substrate, the layer of polymer may coat the section on the opposite side to the substrate, or both. The method comprises a liquid composition, wherein the composition comprises PEDOT, PSS, DMS02 and an organic solvent or polyaniline (emeraldine salt), DMS02 and an organic solvent; and wherein the applying comprises spraying, spin coating or spreading a composition comprising a solvent and the polymer on the surface of the substrate and then removing the solvent by evaporation. Methods of analyzing the sample in this combination are also provided.