The present invention relates to a flow-through device comprising at least one separation column wherein a first packing component, which comprises particles of alumina and/or silica, and a second packing component, which comprises a powder of one or more hygroscopic salts are provided. The two packing components may be blended or layered in the device, which may comprise a single tube or a plurality of tubes arranged in a plate format, such as the wells of a multiwall plate or tubes in a rack. In addition, the invention relates to a method for removing one or more matrix components, such as pigments, from a biological sample, by passing said sample across a first packing component, which comprises particles of alumina and/or silica, and a second packing component, which comprises a powder of one or more hygroscopic salts.