This study is focused on the investigation of the antioxidant effect of tetraethylenepentamine (TEPA) on biodiesel oxidation resistance and metal ion content. The induction period of rapeseed oil biodiesel with different content of TEPA was determined by Rancimat assay. The content of metal elements in the extracted aqueous solution, before and after the addition of TEPA was analyzed by inductively coupled plasma mass spectrometry. The results show that the addition of TEPA chelates the free copper and iron ions in biodiesel and improves the oxidation stability of biodiesel. TEPA is a good antioxidant and chelating agent; however, its Fe3+ chelating ability is weak. (C) 2019 Elsevier Ltd. All rights reserved.