A microfluidic device having a sealed chamber containing a filter for purifying a biological or chemical analyte from a complex biological sample, the chamber is added to the filter, through the first flow path, a first port to allow gas communication between the chamber and the vacuum generator through a second flow path, a second port that allows fluid communication between the chamber and one or reservoir above it, the through the third channel, to store a plurality of ports and a third port that allows gas and liquid communication between the both chambers and one or receiving vessels and vacuum generator above it, first and / or as the fluid exiting from the chamber through the third port enters the chamber through the second port flows through the filter, the filter is, Oyo third port and first port Device is disclosed which is located between the both second port. The present invention also relates to the use of a microfluidic device.