Methods, kits and devices for separating phospholipids and proteins from small molecules in biochemical samples can feature an apparatus having a wetting barrier, at least one frit and a separation media. For example, an apparatus can include at least one wall defining a chamber having an exit and an entrance; a wetting barrier disposed between the exit and entrance, so as to define a separation media space located between the wetting barrier and the exit and a sample receiving area located between the wetting barrier and the entrance; and a separation media disposed adjacent to the wetting barrier and having a specific affinity for phospholipids.