The present invention provides a well-less filtration device that includes a pre-filter layer; a support layer; and at least one layer of solid phase extraction medium disposed between the pre-filter layer and the support layer. At least a portion of the pre-filter layer, support layer and solid phase extraction medium are ultrasonically welded together to form a pattern of filter cells and land areas with the land areas being disposed between the filter cells. The filter cells of the device may be arranged to conform to a standardized array format.