The invention relates to a polymer obtainable by radical co-polymerization of a first monomer of general formula (I) or (II) or a mixture thereof: wherein A, A′, B, B′ X, Y, Y′ and n are as defined herein; with a second, cross-linking monomer and optionally with one or more further co-monomers; wherein the molar ratio of the first monomer to other monomers is less than or equal to 1:5. The polymers selectively bind to phosphate ester compounds and can be used as a solid phase in a method for isolating compounds comprising a phosphate ester group from a mixture comprising one or more phosphate monoesters and/or phosphate diesters and/or other compounds such as lipids.