Scintillation proximity assay for measuring benzene absorption in a polyethylene membrane

A polyethylene membrane that had been exposed to benzene vapor was sandwiched between two carboxylated poly(vinyl chloride) membranes that contained carbon-14 labeled lysine. The beta-particles emitted from carbon-14 were in close enough proximity to the benzene molecules to induce an excitation and subsequent emission of photons. The number of photons produced, as measured in a liquid scintillation counter, was shown to be proportional to the amount of benzene absorbed by the polyethylene membrane and was dependent on membrane thickness. This scintillation proximity assay technique can be used to study absorption/desorption processes of aromatic compounds in polymeric membranes.