Radiolysis products of antioxidants from gamma-irradiated polyethylene resins

Abstract

Radiolysis products from irradiated polyethylene resins were investigated using liquid chromatography coupled to photodiode array (PDA) and mass spectrometry (MS) detection. The resins were gamma-irradiated at applicable doses for food applications. The antioxidants and radiolysis products were extracted using accelerated solvent extraction (ASE) prior to analysis. Tris(2,4-di-tert-butylphenyl) phosphite and tris(nonylphenyl) phosphite (TNPP) were oxidized to form phosphate as the major product. Nonylphenol (from TNPP), and 2,4-di-tert-butyl phenol (from tris(2,4-di-tert-butylphenyl) phosphite) were also produced by the irradiation. Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate formed a dehydrogenated product (loss of two hydrogens). The remaining detectable peaks had low responses suggesting low concentrations. Some of the low concentration products were tentatively identified using information from their fragmentation patterns in the MS/MS spectrum, and high mass accuracy measurements.