Abstract: An apparatus and a method of operating the apparatus are provided for obtaining a sample of polymer cement and for determining the polymer content of the cement and a molecular weight of the polymer. The apparatus comprises a valve means in combination with a dilution means whereby dilute polymer solution is supplied to a solution viscometer means and to a gel permeation chromatographic means. Operation of the apparatus is controlled by a micro computer. The apparatus and method are useful for determining the polymer content and polymer molecular weight of, for example, polybutadiene formed in a polymerization reactor.