A device for separating a liquid sample potentially comprising one or more proteins, phospholipids, and small molecules, the apparatus comprising: a housing having at least one wall defining a chamber having an exit opening and an entrance opening; a wetting barrier element disposed between the exit opening and the entrance opening, so as to define a separation media space located between the wetting barrier element and the exit opening and a sample receiving area located between the wetting barrier element and the entrance opening; and a separation media disposed in the separation media space and held between the wetting barrier element and a second frit, the separation media having a specific affinity for phospholipids, and a core composition and a surface composition represented by formula: W- -Q, wherein X represents the core composition, and W and Q occupy free valences of the core or a surface composition that are not X, the wetting barrier element being provided by a first frit formed of a fluorocarbon polymer and having openings of about 5 to 500 μm for retaining the liquid sample and a protein precipitating agent in the sample receiving area, thereby facilitating the formation of a protein precipitate and a processed sample, and for allowing flow of the processed sample through the wetting barrier element and the separation media under a force which force is a differential gas pressure of greater than 13.545,6 Pa (4"Hg) across the chamber or a centrifugal force equivalent thereto, thereby retaining the protein precipitate in the sample receiving area and phospholipids in the separation media while eluting small molecules, characterized in that X is silica, W is hydroxyl, Q is an aliphatic group with the formula Si-R 1, and R 1 has eighteen carbons, and the hydroxyl and aliphatic group have a concentration on said surface forming a ratio of concentration, said ratio of hydroxyl to Si-R 1 being 3.5 -14. a housing having at least one wall defining a chamber having an exit opening and an entrance opening; a wetting barrier element disposed between the exit opening and the entrance opening, so as to define a separation media space located between the wetting barrier element and the exit opening and a sample receiving area located between the wetting barrier element and the entrance opening; and a separation media disposed in the separation media space and held between the wetting barrier element and a second frit, the separation media having a specific affinity for phospholipids, and a core composition and a surface composition represented by formula: W- -Q, wherein X represents the core composition, and W and Q occupy free valences of the core or a surface composition that are not X, the wetting barrier element being provided by a first frit formed of a fluorocarbon polymer and having openings of about 5 to 500 μm for retaining the liquid sample and a protein precipitating agent in the sample receiving area, thereby facilitating the formation of a protein precipitate and a processed sample, and for allowing flow of the processed sample through the wetting barrier element and the separation media under a force which force is a differential gas pressure of greater than 13.545,6 Pa (4"Hg) across the chamber or a centrifugal force equivalent thereto, thereby retaining the protein precipitate in the sample receiving area and phospholipids in the separation media while eluting small molecules, characterized in that X is silica, W is hydroxyl, Q is an aliphatic group with the formula Si-R 1, and R 1 has eighteen carbons, and the hydroxyl and aliphatic group have a concentration on said surface forming a ratio of concentration, said ratio of hydroxyl to Si-R 1 being 3.5 -14.