Disclosed is a method for performing the steps of nucleic acid template purification, thermocycling reaction and purification of the products of the thermocycling reaction characterized in that the steps take place sequentially in a microfluidic disc. Also disclosed is a microstructure for fluids comprising at least one inlet opening connected to a first chamber incorporating a means for purifying template nucleic acid which, in turn, is connected to a second chamber incorporating a means for a thermocycling reaction which, in turn, is connected to a third chamber incorporating a means for purifying products of the thermocycling reaction, and a microfluidic disc comprising a plurality of such microstructures.