The present invention is directed to novel device comprising a sol-gel filled microchannel and methods for purifying nucleic acids from biological samples. In one embodiment shown in FIG. 1, the microfluidic device (1) comprises a base (2) with a microchannel (3) formed in the interior of base (2), wherein said microchannel (3) is filled with a sol-gel matrix and in fluid communication with an inlet port (4) and outlet port (5) wherein inlet port (4) and outlet port (5) are formed on the exterior surface (10) of base (2). The device may be further provided with additional components to allow for analytical analysis of the purified nucleic acid sequences.