Abstract: A microfluidic device is for processing and aliquoting a sample liquid. The microfluidic device has a dividing chamber for receiving a starting volume of the sample liquid. The dividing chamber has a plurality of cavities for receiving sub-volumes of the sample liquid, the sub-volumes being usable for analytical reactions. The microfluidic device also has a microfluidic network for using the dividing chamber in a fluid-mechanical manner and at least one pump device for pumping fluids within the device. The at least one pump device and the microfluidic network are configured to pump the sample liquid, as a first phase, and a sealing liquid, as a second phase, through the microfluidic network and into the dividing chamber in order to seal the sub-volumes of the sample liquid in the cavities using the sealing liquid.