Described is a device for solid phase extraction of a dried sample of a biological fluid. The device includes a support structure such as a plate or support block that has a first side to receive a dried sample card. The support structure also has a second side that is opposite the first side and a number of apertures that extend between the first and second sides. The device also includes a plurality of wells each containing a sample preparation material and having an inlet end that communicates with a respective aperture at the second side of the support structure. Each dried sample on the dried sample card is aligned with one of the apertures. Extraction samples in each well pass through the sample preparation material, such as a chromatographic sorbent, in the well to remove one or more constituents of the extraction sample.