A microfluidic device comprises a microfluidic channel having at least an inlet for receiving a fluid plug or an outlet for removing a fluid plug and a pillar based flow distributor for reorienting the fluid plug in such a way that the long axis of the fluid plug essentially is oriented perpendicular to the walls of the microfluidic channel, as opposed to its original orientation, in which the longer axis is oriented in the longitudinal direction of the narrower inlet channel. The width W of the microfluidic channel is substantially larger than the width w of the inlet or outlet channel. The microfluidic device is adapted for detecting a physical or chemical property of the fluid, the microfluidic device being configured for detecting the property in a detection area positioned across the microfluidic channel in a width direction of the microfluidic channel.