The invention relates to a microfluidic device comprising an inlet port for liquid, a capillary channel in fluid connection to the inlet port for receiving liquid from the inlet port, the channel having a defined volume. At least one dissolvable valve is provided comprising a dissolvable membrane having a first side oriented towards the capillary channel, and capillary means connected to the second side of the dissolvable membrane such that when the membrane is dissolved by the liquid, liquid is transported through the valve to the second side of the membrane by capillary action. The invention relates to uses of the device, methods of fabricating the device and method of controlling a flow of liquid.