Abstract: An apparatus and method for analysing temperature-dependent molecular configurations such as folding comprises a multi-channel flow-through chip (12) along which molecules to be analysed pass. A temperature gradient is maintained along the length of the chip. As molecules pass along the channels they fold or unfold, in response to the changing temperature. These changing molecular configurations are investigated by simultaneously measuring the extent to which the molecules absorb UV light, and the extent to which they fluoresce. The absorption and fluorescence information is supplied to a computer system (26) for real-time analysis.