GEL PERMEATION CHROMATOGRAPHY (GPC) – Gel Permeation Chromatography (GPC) is to be performed for PVC materials using liquid chromatography that employs a porous gel as a separation medium. This method is designed to analyze the organic-soluble non-resin PVC compound components (for example, plasticizers) that appear within the working range of the column bank. This analysis is further described in the Gel Permeation Chromatography section of the Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581.