Determination of styrene and 2-vinylpyridine monomers in poly(2-vinylpyridine—styrene)

Abstract Residual monomers such as styrene can be determined in polymers at microgram per kilogram concentrations by headspace techniques. However, such techniques often do not have adequate sensitivity for the determination of monomers less volatile than styrene. A method is described for the determination of trace concentrations of monomers that are less volatile than styrene and also monomers that are traditionally determined in polymers by headspace techniques. The method involves dissolution of the polymer, removal of the polymer by molecular ultrafiltration and determination of the monomer in teh filtrate by gas chromatography—mass spectrometry. Concentrations of styrene and 2-vinlpyridine of less than 200 μg/kg were successfully determined in a copolymer used for the post-ruminal delivery of nutritional supplements and drugs.