Antioxidant analysis incorporating a thin-layer chromatographic separation procedure

Abstract

The method described consists of three distinct and separate steps. Initially, a thin-layer chromatographic technique, involving the use of mixed silica gel-aluminium oxide plates, is used to separate and identify the extracted antioxidants. This step is followed by confirmation of the suspected identity and determination of the antioxidant by using infrared and ultraviolet spectroscopy.This method is considered applicable, over a range of concentrations, to the analysis of both antioxidants and ultraviolet screening compounds possessing ultraviolet absorbing properties, in polyolefinic polymers such as polyethylene, polypropylene, poly(4-methylpentene), etc. It can be used to detect such additives down to a level of 200 µg g–1, and possibly even less, in a given polymer.In addition, the procedure has been successfully applied to the separation of isomeric antioxidants and to the identification of antioxidants present in lubricating oils.