The ability to sensitively detect and analyze large molecules and their reaction products is important for the analysis of biological materials, including medical samples, plants and foods. Such analyses present special challenges in terms of the need to selectively extract the compound or class of compounds in order to separate them from the complex mixture found in biological samples. In addition, conventional techniques for separating and identifying relatively small molecules are not applicable to high molecular weight materials where the volatility is low and they are often viscous liquids or solids at room temperature.