The Mastro2 column has a biocompatible PEEK-lined stainless steel body with a high pressure polymer frit. This inertness eliminates adsorption and reduces tailing for compounds that tend to form chelates with metal surfaces, especially those containing phosphate groups. The PFP phase provides alternate selectivity for compounds that have low retention or are poorly resolved with a C18 phase. Maximum operating pressure 40 MPa (400 bar/6000 psi); pH range 2.0 - 7.5; maximum temperature 80C (pH 3 or higher.) Replacement for SSOT-G10006