Abstract: A method for analyzing a sample containing a plurality of analytes, comprises labelling the analytes with a detectable label, the label being chosen such that its detectability can be influenced by modifying the conditions of detection; separating the labelled analytes, before or after labeling,; and determining the presence of the separated analytes under the modified conditions and also, if desired, the unmodified conditions. Suitable detection apparatus comprises a support for a gel, means for detecting one or more analytes in the gel, and means for reducing the temperature of the gel to below ambient temperature, e.g., to no more than 0°C.